1986 Ford Mustang 5.0 EFI swap

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wstefan20
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1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

Been lurking for a while and I'm finally going to start on a build for my friend's Ford Mustang 5.0.

A little background on me, I am an electrical engineer working in research and have some slight experience in PCB design, though I would not call me an expert by any means.

As a warning (and yes, I know I'm going to get flack for this) but I learned PCB design with Eagle and then Fusion 360 so I'm going to be designing everything for my build using that platform. I've been told it's pretty easy to port from Eagle to KiCad though so I might convert them once I get it done in Fusion.

I will be running an MSD ignition and probably speed density to begin with. The goal is to swap my friend's 5.0 from carb to EFI using a stock harness (though I will be going through and cleaning up the harness to so yes, I know it's probably unnecessary). To keep costs down I plan on re-using the stock mustang computer connector and case.

While I know that it's much easier to just rely on prior designs and use the 60 pin breakout board, I really want something custom that doesn't require a bunch of janky jumpers (not bashing just preference), and I won't require a lot of circuitry for this build that is included in generic builds. What would be nice is if I got a base tune, board, and everything and could help other mustang owners from paying $300+ for a stock computer (A9L is getting crazy).

I do work full-time, working on my Master's degree in EE, have more projects in my garage then I'd like to admit, and have a newborn so this might be a bit slow-paced.

As a start, I created a library for the ford 60 pin connector for Eagle and will layout the board once I get the old computer for measurements.

TL,DR:
https://github.com/wstefan20/5.0mustangProteusPnP
https://github.com/rusefi/proteus-mustang5.0-60-pin
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by AndreyB »

Hello and welcome!

For the love of all things good, please use either Frankenso or Proteus schematics 100% as is if possible for you PnP board. You really want to have either Proteus or Frankenso firmware working as is.
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
wstefan20
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

Hello Andrey! Thanks for the words of advice! I was leaning towards Proteus and just leaving off the parts of the circuit I won't be using such as the ignition coil drivers etc. But leaving the design as is. Might add some circuit protection as I've used "ideal diode IC" on automotive circuit applications to prevent against hooking things up in reverse as well as some ESD protection for the pins. Probably overkill but I'd rather make it as bullet-proof as I can!

I will warn in advance that my circuit schematic skills aren't very pretty but they work. Definitely open to criticism!
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mck1117 »

wstefan20 wrote:
Fri Dec 11, 2020 3:10 am
Hello Andrey! Thanks for the words of advice! I was leaning towards Proteus and just leaving off the parts of the circuit I won't be using such as the ignition coil drivers etc. But leaving the design as is. Might add some circuit protection as I've used "ideal diode IC" on automotive circuit applications to prevent against hooking things up in reverse as well as some ESD protection for the pins. Probably overkill but I'd rather make it as bullet-proof as I can!

I will warn in advance that my circuit schematic skills aren't very pretty but they work. Definitely open to criticism!
Not using the coil drivers? Huh? The board has 5v logic level outputs, not dumb coil drivers (IGBT).

There is already some ESD protection - the analog and digital inputs have RC filters and clamp diodes, and the digital outputs are all clamped internally (and have RC filters on some). Likewise the power supply is protected with a reverse diode (schottky) in addition to load dump protection with a hefty bidirectional TVS.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

Andrey, you're probably right. I have not had a chance to really dig into the diagrams yet as I finally got the old ecu from my friend (see picture of layout). Now that I'm looking into the board more I realize there are no "coil drivers" :lol: so it's looking like I'll basically take the Proteus layout and lay it out on the board minus the pins and traces I don't need.

Image

This is an 85 5.0 ecu (if you can call it that) because the connector is physically the same size as the A9L connector as far as how it fits in the case. The tabs are offset on the connector though so I can't actually use the 85 connector. My reasoning for choosing this ecu is that they are a dime a dozen and you can usually find them in the junkyard and on local marketplaces for next to nothing but they will hold the correct connector well and serve as a "factory" looking device which is my goal. The overall box dimensions are also very similar to the A9L so those switching from them will be able to fit them in the stock location if they choose so it is "plug and play". It should also be very easy since it's just thin sheet metal to modify it for USB/other connectors.

My thought for those switching from the A9L or A9P is that yeah, you have to go buy another ECU to cannibalize, but they're cheap, and then you can go sell your stock ECU for $300 or keep yours as a backup!

The downside to using this case is that it is in no way waterproof so the PCB will require some sort of Silicon treatment to prevent corrosion.

Plus, just because I picked this shape doesn't mean you couldn't get a custom waterproof case fabricated down the line. Heck, you could even 3D print your own case (might make a simple one later just cause).
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wstefan20
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

So I've started combing through the wiring diagrams to see what I need to populate.

From what I've gathered, there isn't anyone who's messed with ford's TFI ignition here and since I've already got a perfectly good MSD ignition on it I'll use that to be easier but I'll still route the pcm for it in case anyone wants to mess with it.

I'm not going to mess with the VSS on my build since I'll be doing speed density for simplicity plus my 86 is already mechanical speedo, but I'd like to wire it up for those who want MAF or have electronic speedo. Still have to figure out how to do this with rusEFI.

Again, since I'm choosing speed density I will not be using the MAF sensor, but I will still wire it in case someone else wants to, or I change my mind.

I'm of course deleting the EGR valve position sensor, canister purge solenoid, TAB, TAD, EGR vacuum regulator solenoid, and other emissions stuff so the EEC relay is kind of useless so I'll bypass it so the fuel pump relay still works. Might still wire up the signal wire on the pcb in case people don't want to do that but I'm definitely not bothering messing with wiring up the emissions stuff.

While I'm doing reckless stuff, I'm going to bypass the clutch engage switch and the neutral gear switch as well as bypass the inertia switches. Again, I will probably still wire the board to sense this in case someone cares.

Won't need the WOT cutout relay so I'm deleting that.

This car doesn't have a place for AC so I'm deleting that, but I'm debating an output for electric fans and AC assuming rusEFI supports them.

I could be mistaken, but it looks like I should be able to keep the stock map and tps.

I haven't taken them off yet but am I assuming stock o2 sensors will not work and I'll need to run a wideband o2? Is there any point keeping them?

Other question is whether rusEFI supports the idle air bypass valve and has code for this or would I need something crazy? I'm assuming the thing would try to stall out without it though so might need some help on that.

All this cuts the pins used from 44 down to 27 which should clean up the harness a ton.

Below is the very rough diagram of what I'm removing to give me an idea what my plan is.

Image
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mck1117 »

wstefan20 wrote:
Tue Dec 29, 2020 5:14 am
This car doesn't have a place for AC so I'm deleting that, but I'm debating an output for electric fans and AC assuming rusEFI supports them.
Both are supported to be controlled from the ECU!
wstefan20 wrote:
Tue Dec 29, 2020 5:14 am
I could be mistaken, but it looks like I should be able to keep the stock map and tps.
Yep!
wstefan20 wrote:
Tue Dec 29, 2020 5:14 am
I haven't taken them off yet but am I assuming stock o2 sensors will not work and I'll need to run a wideband o2? Is there any point keeping them?
You've got it. Narrowband sensors are pretty much useless for tuning, so wideband is required.
wstefan20 wrote:
Tue Dec 29, 2020 5:14 am
Other question is whether rusEFI supports the idle air bypass valve and has code for this or would I need something crazy? I'm assuming the thing would try to stall out without it though so might need some help on that.
Yes, PWM idle valves are supported.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

Thanks mck1117! Glad I'm on the right track.

I'm used to cars with cam and crank sensors for timing so maybe I'm missing something, but if I use the MSD ignition rather than TFI, how would the ecu know when and what order to fire the injectors? I'm assuming the tach might be "good enough" to do timing but not firing order. Is there a solution to this or am I just missing some simple answer?

Once that question is answered I can probably start the actual design of the board. Shout out to the designer of the Proteus board schematics. I am also going to try to replicate the module approach to simplifying the layout but this is my first time using modules so we'll see how that goes! :lol:
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mck1117 »

wstefan20 wrote:
Tue Dec 29, 2020 7:31 am
I'm used to cars with cam and crank sensors for timing so maybe I'm missing something, but if I use the MSD ignition rather than TFI, how would the ecu know when and what order to fire the injectors? I'm assuming the tach might be "good enough" to do timing but not firing order. Is there a solution to this or am I just missing some simple answer?
You have it right. With just N teeth (and no missing tooth), you can get engine speed but not the exact phase, so you can't really do sequential fueling (well, you can, but it's a 1-in-N random draw about which phasing you get).

I'm not sure you really want to use the MSD ignition - you get much better configuration options when also running ignition off the ecu. Is the MSD in question a whole distributor with integral sensor, or an external ignition box that uses a normal locked out points distributor as its engine phase/speed source? Either way, I'm sure there's an inexpensive solution to fit a missing tooth wheel on the crankshaft. I'm pretty sure your engine came with EDIS on later Mustangs, Explorers, etc, so you might even be able to cobble together a nearly-OEM trigger wheel/sensor setup.

There's a good chance that if it's a non-distributor MSD ignition box you can configure it to not change the advance, and just fire it from the ECU as if it was the coil.
wstefan20 wrote:
Tue Dec 29, 2020 7:31 am
Once that question is answered I can probably start the actual design of the board. Shout out to the designer of the Proteus board schematics. I am also going to try to replicate the module approach to simplifying the layout but this is my first time using modules so we'll see how that goes! :lol:
Hey, that's me! 8-)

Easiest compatibility is if you can try an keep the STM32's pinout the same, so that you don't have to modify the firmware at all to get up and running.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mck1117 »

BTW you can run crank-sensor-only just fine, especially with a distributor. Sequential fueling isn't quite the holy grail that the internet makes it out to be. Sure, it'll get you those last few percent on emissions or fuel economy, but it requires hours on an engine dyno to find those. I run my LS V8 with just a crank sensor in wasted spark mode (individual coils, but firing pairs opposite in the firing order) and you can't tell it isn't running "full sequential".
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mk e »

mck1117 wrote:
Tue Dec 29, 2020 11:44 am
BTW you can run crank-sensor-only just fine, especially with a distributor. Sequential fueling isn't quite the holy grail that the internet makes it out to be. Sure, it'll get you those last few percent on emissions or fuel economy, but it requires hours on an engine dyno to find those. I run my LS V8 with just a crank sensor in wasted spark mode (individual coils, but firing pairs opposite in the firing order) and you can't tell it isn't running "full sequential".
Semi-sequential injection, pair just like waste spark, works fine. The dead time and short pulse stuff plays a bigger role and you can't really get all the fuel evaporated before the intake opens so the low power mixture varies a little, but it runs fine. Perfectly good as you says.


Multipoint, where all the injectors fire together is the devil. I played around with this years ago when I upgraded to my first ECU capable of sequential, it was the same brand ECU so I just loaded the multipoint tuning to get running, needed almost nothing changed. Then did a new tune for sequential...there was really no comparison in idle quality, on multipoint it sounded like a V8 with big cam lopping along, switch to sequential and it was oem smooth. Also different cylinders run different due to different fuel timing, it was obvious on the plugs that had to be replaced every month or 2.

I would never do another setup with no control of injection angle like you'd get with a non-missing tooth crank wheel or rpm based fuel using the tach signal....both will produce pretty inconsistent results and an engine that just never runs right. A way better use of time is to use the time to get at least a missing tooth wheel mounted and then just buy a proteus and have a good setup....you can always find a use for more I/O (all can be reconfigured to do whatever you want) but a car that doesn't ever run well in of very limited use.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

mck1117 wrote:
Tue Dec 29, 2020 11:24 am
You have it right. With just N teeth (and no missing tooth), you can get engine speed but not the exact phase, so you can't really do sequential fueling (well, you can, but it's a 1-in-N random draw about which phasing you get).
Glad to hear my logic is still sound! haha
mck1117 wrote:
Tue Dec 29, 2020 11:24 am
I'm not sure you really want to use the MSD ignition - you get much better configuration options when also running ignition off the ecu. Is the MSD in question a whole distributor with integral sensor, or an external ignition box that uses a normal locked out points distributor as its engine phase/speed source?
Actually, that's a good question. I believe it is a 6AL with a generic distributor but I'll have to take a closer look. Only reason I was thinking it was a good option is that it's already there and I don't need to buy any other parts, but if it's going to cause issues I guess I should probably look at other options.
mck1117 wrote:
Tue Dec 29, 2020 11:24 am
Either way, I'm sure there's an inexpensive solution to fit a missing tooth wheel on the crankshaft. I'm pretty sure your engine came with EDIS on later Mustangs, Explorers, etc, so you might even be able to cobble together a nearly-OEM trigger wheel/sensor setup.
Not a bad idea! I'll have to look. I know they made this engine for some time so it's not unreasonable to think there's a factory solution. I should probably change the timing cover anyhow since it's got all the mechanical fuel pump stuff. I've been told you can leave it and just use a block-off plate but it would probably clean things up a bit and I've got a leak there anyhow.
mck1117 wrote:
Tue Dec 29, 2020 11:24 am
Hey, that's me! 8-)
Well kudos to you! Cleanest diagrams I've seen actually. If you don't mind me asking, where did you learn? I'm an electrical engineer working in research and they never even had a class on PCBs! :lol: I've just been learning as I go, though it's definitely a steep learning curve!
mck1117 wrote:
Tue Dec 29, 2020 11:24 am
Easiest compatibility is if you can try an keep the STM32's pinout the same, so that you don't have to modify the firmware at all to get up and running.
Agreed! I was contemplating making this a 4 layer board for EMI and ease of routing purposes. I like how you've laid everything out too so I will probably end up just leaving off the traces I won't need and keeping everything else the same.

Has anyone used the stock TFI? From my limited understanding it supplies a waveform and receives kind of a crank signal? Theoretically this shouldn't be too bad, but if there's no code for this, it might be a nightmare! I've done a good bit of C and C++ coding, but that's definitely not my specialty, especially at a low level...
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

So it looks like I really have three options here:

1) Figure out some way to get the TFI system working and buy the TFI distributor and coil.

2) The late ford explorers were converted to ignition coils with a cam/crank sensor which would be easy to control from rusefi. Downside is that I would have to completely swap the accessory drive and components and deal with a fan that's further back so I at very least will run into clearance issues and need an adapter for the power steering pump. This is an option since I go to the junkyard regularly and there's no shortage of explorers, but still pretty pricey, plus I just replaced a bunch of the accessories so that'd be a waste.

3) Turns out 96 bronco's balancer had a 4 tooth wheel pressed on the balancer for misfire detection which just happens to be the exact same size and position for the pressed on reluctor from the late explorer. This means if I can find the balancer from the 96 (it's pretty rare apparently), I can get the timing cover from the 96 which is identical to the mustang with the added mounting bolts for the crank sensor. This method does not require me to change all the accessories, so in my mind, this is the better option. This will still require me to get the camshaft position sensor, timing cover, two balancers, ignition coils, crankshaft position sensor, and various connectors. Overall this should still be cheaper than option 2 and will probably be my choice.

If anyone has any input or experience with these engines please let me know!
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

mck1117 wrote:
Tue Dec 29, 2020 11:44 am
BTW you can run crank-sensor-only just fine, especially with a distributor. Sequential fueling isn't quite the holy grail that the internet makes it out to be. Sure, it'll get you those last few percent on emissions or fuel economy, but it requires hours on an engine dyno to find those. I run my LS V8 with just a crank sensor in wasted spark mode (individual coils, but firing pairs opposite in the firing order) and you can't tell it isn't running "full sequential".
Good to know! Silly question... since this is a custom build, and since I'm using a cam sensor, is there anything stopping me from using a different coil pack that isn't wasted spark? And is it any more difficult to set-up? Sorry, pretty new to ignition schemes.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

mk e wrote:
Tue Dec 29, 2020 3:11 pm
Semi-sequential injection, pair just like waste spark, works fine. The dead time and short pulse stuff plays a bigger role and you can't really get all the fuel evaporated before the intake opens so the low power mixture varies a little, but it runs fine. Perfectly good as you says.


Multipoint, where all the injectors fire together is the devil. I played around with this years ago when I upgraded to my first ECU capable of sequential, it was the same brand ECU so I just loaded the multipoint tuning to get running, needed almost nothing changed. Then did a new tune for sequential...there was really no comparison in idle quality, on multipoint it sounded like a V8 with big cam lopping along, switch to sequential and it was oem smooth. Also different cylinders run different due to different fuel timing, it was obvious on the plugs that had to be replaced every month or 2.

I would never do another setup with no control of injection angle like you'd get with a non-missing tooth crank wheel or rpm based fuel using the tach signal....both will produce pretty inconsistent results and an engine that just never runs right. A way better use of time is to use the time to get at least a missing tooth wheel mounted and then just buy a proteus and have a good setup....you can always find a use for more I/O (all can be reconfigured to do whatever you want) but a car that doesn't ever run well in of very limited use.
Good to know! So if I have a cam and crank signal, would it be any more difficult to get a different coil pack and do full sequential ignition rather than wasted spark? The reluctor wheel is a 35 missing tooth style and I think the cam is two wire hall?
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mk e »

Everything you're talking about was done in the 80s & 90s and isn't done anymore....because none of it works very well and you'd be much better off with a good carb than any of that IMO. Nobody plans to fail, they simply fail to plan and that is where I fear you are heading looking for shortcuts around a good system design, lots of ways to make it run, not so many to make it run good. Copy a good system and you will be happy, copy/install a 1 year only design from 30 years ago and you will not.

You REALY want to get a missing tooth wheel installed if you want it to run right with EFI or come up wiht a clever way to get the same functionality.

I've done this many different ways on different engines over the years, its never very hard...a weekend or 2 at most and its done.

you can buy something here:
https://www.diyautotune.com/shop/sensors-data-logging/trigger-wheels/

bolt to the front or back of the front pully is generally the easiest. On 308 ferraris I add pins to the back of the flywheel that work with the OEM ignition trigger. I've used spockets with a tooth or 2 ground off. A sensor in the cam cover or rocker cover watching the rocker more....there is always a way. I can't imaging someone isn't selling a kit for that engine? If you have a distributor you can mount 2 wheels in it and get both cam and crank position....remember you are now talking aftermarket ECU so it doesn't matter if the setup was stock or exactly how you time the sensor to the wheel or wheel to the crank, those are setup parameters in the ECU you you set set how you please, but I've never seen a setup that is worth a sh_t that doesn't include a way for the ECU to know crank position.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mk e »

wstefan20 wrote:
Tue Dec 29, 2020 5:36 pm


Good to know! So if I have a cam and crank signal, would it be any more difficult to get a different coil pack and do full sequential ignition rather than wasted spark? The reluctor wheel is a 35 missing tooth style and I think the cam is two wire hall?
Once you have cam & crank position you can use any ignition you please really from sticking with a distributor to COP or anything in between. The important part I'm talking about is consistent fuel mixture and for that you really need to know at least crank position, like with a missing tooth wheel.

I don't think it matters if you use hall or reluctor crank or cam....it can be a little harder to get a good reluctor signal at cam speed so most go hall on that, but years about I put ford distributor guts on a cam and it worked fine. What I have learned the hard way it to make sure and decide BEFORE you choose a wheel as they are not necessarily interchangeable...hall needs enough space tooth to tooth and reluctor needs the right tooth profile to match the specific sensor you plan to use.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

mk e wrote:
Tue Dec 29, 2020 6:08 pm
Once you have cam & crank position you can use any ignition you please really from sticking with a distributor to COP or anything in between. The important part I'm talking about is consistent fuel mixture and for that you really need to know at least crank position, like with a missing tooth wheel.

I don't think it matters if you use hall or reluctor crank or cam....it can be a little harder to get a good reluctor signal at cam speed so most go hall on that, but years about I put ford distributor guts on a cam and it worked fine. What I have learned the hard way it to make sure and decide BEFORE you choose a wheel as they are not necessarily interchangeable...hall needs enough space tooth to tooth and reluctor needs the right tooth profile to match the specific sensor you plan to use.
Good to know! I know there's not a big advantage to full sequential ignition vs wasted spark as there isn't a big difference between full sequential injection vs batch if we're talking mostly stock applications. I'll probably go with sequential fuel injection and wasted spark ignition, but I will try to wire up the ecu so that I can change my mind later and just go with LS style coil packs since I have plenty of pins to work with. Since I can get almost all the parts from the junkyard it won't be all that expensive either!
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mk e »

wstefan20 wrote:
Tue Dec 29, 2020 6:23 pm


Good to know! I know there's not a big advantage to full sequential ignition vs wasted spark as there isn't a big difference between full sequential injection vs batch if we're talking mostly stock applications. I'll probably go with sequential fuel injection and wasted spark ignition, but I will try to wire up the ecu so that I can change my mind later and just go with LS style coil packs since I have plenty of pins to work with. Since I can get almost all the parts from the junkyard it won't be all that expensive either!
That sound like a fine plan.

Batch and semi-sequent5ial are different. Semi-sequential is fine just like waste spark. Batch injection...well sucks is the best word so I suggest you stay away for that. Batch came about, late 80s? to help keep fuel rail pressure more even than was seen with multipoint when you fire all the injectors at once. Its all the issues of multipoint x2.

My current project ECU, (not a rusEFI) doesn't have the FW channels for direct fire ignition on a 12cyl, so I use LS style coils wired for waste spark. The only issue is it sucks more power...I have 40A just feeding the coils, 30A to the fuel pump, 20A to injectors. It all adds up..my OEM alternator is a 85A so redline WOT is pulling from the battery even before the headlights are on. That is the only downside to waste spark...unless rpm gets so high you also run into dwell time problems but you need to spin it pretty frikin fast to worry too much about that.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

mk e wrote:
Tue Dec 29, 2020 6:45 pm
Batch and semi-sequent5ial are different. Semi-sequential is fine just like waste spark. Batch injection...well sucks is the best word so I suggest you stay away for that. Batch came about, late 80s? to help keep fuel rail pressure more even than was seen with multipoint when you fire all the injectors at once. Its all the issues of multipoint x2.
Owch. Good to know! And glad I picked semi-sequential! :lol:
mk e wrote:
Tue Dec 29, 2020 6:45 pm
My current project ECU, (not a rusEFI) doesn't have the FW channels for direct fire ignition on a 12cyl, so I use LS style coils wired for waste spark. The only issue is it sucks more power...I have 40A just feeding the coils, 30A to the fuel pump, 20A to injectors. It all adds up..my OEM alternator is a 85A so redline WOT is pulling from the battery even before the headlights are on. That is the only downside to waste spark...unless rpm gets so high you also run into dwell time problems but you need to spin it pretty frikin fast to worry too much about that.
Wow! I didn't even think about the current draw. I too have the stock alternator at the moment so I should be fine with semi, but I'd be in for an upgrade for full sequential. Sounds like the semi-sequential is definitely the way to go here since I doubt it'll go anywhere near 6k. I don't think the stock 302 would like that very much...

I mainly want to create an alternative to Megasquirt plug and play and stock ECU which are the only current options on the market for plug-and-play top swap. If I can get away with keeping the stock plug and just adding and removing a few pins here and there, this would be much more feasible for the DIY community since most people out there aren't Electrical Engineers and don't want to mess with a completely custom harness that'll run them well over a grand.

If there's any features you or anyone think I'm missing here I would appreciate the input! I'm going to start working on the revised wiring diagram!
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mk e »

Full sequential fuel uses a bit less power the semi-sequential as the injectors are on a bit less total time, small difference though....10% or so depending.

Direct fire ignition uses 1/2 the power as waster spark ignition, and about the same as distributor depending on the coils in each.

What exact features the ECU NEEDS is setup dependent. Most people will add features once they realized they can have them...I've never in my life had an ECU I didn't use up all the pins on and not get to the end of my wish list. If you have room for something like a pigtail that plugs to the stock harness with the rest available on another connector or an adapter board to have the OEM connector plus an extra with no pigtail, it would be a much better product IMO.

I'm also pretty confused right now as you were talking about how to cobble together a working trigger. How is it possible the stock harness has everything you need but there is no functional trigger setup?
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

mk e wrote:
Tue Dec 29, 2020 8:17 pm
Full sequential fuel uses a bit less power the semi-sequential as the injectors are on a bit less total time, small difference though....10% or so depending.

Direct fire ignition uses 1/2 the power as waster spark ignition, and about the same as distributor depending on the coils in each.
That makes total sense now. I think I'll still have enough current for my needs since this is a fairly stock build. I might upgrade later, but this should run ok for now at least.
mk e wrote:
Tue Dec 29, 2020 8:17 pm
What exact features the ECU NEEDS is setup dependent. Most people will add features once they realized they can have them...I've never in my life had an ECU I didn't use up all the pins on and not get to the end of my wish list. If you have room for something like a pigtail that plugs to the stock harness with the rest available on another connector or an adapter board to have the OEM connector plus an extra with no pigtail, it would be a much better product IMO.
Yeah, I'm still going back and forth on how I'm going to do this. The factory harness didn't use many of the pin locations so I was thinking of for my personal build doing a custom harness, well, because I can, but for the "general public" I'd make sure not to use any pins used in stock even if I'm not hooking them up at all in case someone just wants to use the stock harness.
mk e wrote:
Tue Dec 29, 2020 8:17 pm
I'm also pretty confused right now as you were talking about how to cobble together a working trigger. How is it possible the stock harness has everything you need but there is no functional trigger setup?
Sorry. I wasn't to clear on that one. I'm still going to connect MAF and the TFI module pins correctly in case someone wants to mess with it, but I'm also going to add provisions for both semi-sequential and full-sequential ignition as well which is the option I'll be choosing. Basically I'll be adding a cam and crank sensor from an 01 explorer with a modified balancer and timing cover from a 96 bronco so I can keep my stock accessories but add the trigger (I could swap all accessories from the explorer too, I'm just trying to simplify stuff).

Basically my plan is to create this so that you can take a stock harness and add pins to the stock connector which is much easier than having to do a full custom harness (even though I'll be doing mine custom).

My thought is that if someone wanted to make an adapter with pigtail rather than adding pins they could do that too, that way you really could easily go back to stock. This should be pretty easy the way I'm laying out the pins, but personally I'm just going to re-pin my harness custom anyhow because I can :lol:

I think the only thing that looks like I'm missing is the tach signal. I know stock this is from the coil positive since it fires every cylinder. Does rusEFI have the ability to calculate the tach from the cam/crank? If so that'd be ideal so I don't have to buy an aftermarket converter or something crazy. I should note I'm not running a VSS. Would this affect anything as well?

I'm working on the wiring diagram of what I'm planning on doing so it's all laid out 100% before I ever start messing with the board layout.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

Also, I've heard rumors of wideband o2 controller onboard one of the boards. Is this something feasible? If not, I'm guessing most wideband o2 sensor controllers output 0-5V and I can just hook this up to one of the analog inputs?
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mk e »

wstefan20 wrote:
Tue Dec 29, 2020 10:00 pm

Sorry. I wasn't to clear on that one. I'm still going to connect MAF and the TFI module pins correctly in case someone wants to mess with it, but I'm also going to add provisions for both semi-sequential and full-sequential ignition as well which is the option I'll be choosing.

ignition is:
distributor, waste spark, direct fire. all are fine.

Fuel is
multipoint (some might call it batch), semi-sequential, (full) sequential. ?Multipoint, batch, bank....anything with a name like that is a sad option. semi or full sequential are fine.

So again, what exactly are you doing?

I ask, again, because it loos like I'm talking/cautioning about the importance of good fuel control and you're talking about ignition?

I'm also still having trouble wrapping my head around a factory harness that doesn't have the sensors needed for sequential injection but does have each injector wired separately? and has all the other sensors needed? That seems unlikely meaning the ECU you're plotting will only ever work right with a custom harness so you're product maybe should be a proteus wiring harness for fox body mustangs? Plug and play only works on cars that have something useable to plug into right? Or find a later model harness you (or anyone) can easily modify and be p&p with that harness?


wstefan20 wrote:
Tue Dec 29, 2020 10:00 pm
I think the only thing that looks like I'm missing is the tach signal. I know stock this is from the coil positive since it fires every cylinder. Does rusEFI have the ability to calculate the tach from the cam/crank? If so that'd be ideal so I don't have to buy an aftermarket converter or something crazy. I should note I'm not running a VSS. Would this affect anything as well?
I'm not a rusEFI user so I'll let one of them answer...but I can't imagine an ecu that can calculate when to fire fuel and coils within a few micro seconds but not how to send out 4 pulses/rev to the tach ;)
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mck1117 »

mk e wrote:
Tue Dec 29, 2020 10:37 pm
wstefan20 wrote:
Tue Dec 29, 2020 10:00 pm
I think the only thing that looks like I'm missing is the tach signal. I know stock this is from the coil positive since it fires every cylinder. Does rusEFI have the ability to calculate the tach from the cam/crank? If so that'd be ideal so I don't have to buy an aftermarket converter or something crazy. I should note I'm not running a VSS. Would this affect anything as well?
I'm not a rusEFI user so I'll let one of them answer...but I can't imagine an ecu that can calculate when to fire fuel and coils within a few micro seconds but not how to send out 4 pulses/rev to the tach ;)
mk e is correct - the tach output is completely independent of fuel/ign, so you can actually run any number of pulses per rev (even fractional) on any engine.

VSS is very much not required, but does work if you want it wired to the ECU as well.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

mk e wrote:
Tue Dec 29, 2020 10:37 pm
So again, what exactly are you doing?
Sorry. I'm still getting used to the naming conventions. For ignition, my plan is to do waste spark but also populate extra pins so that I could switch to direct fire later.
mk e wrote:
Tue Dec 29, 2020 10:37 pm
I'm also still having trouble wrapping my head around a factory harness that doesn't have the sensors needed for sequential injection but does have each injector wired separately? and has all the other sensors needed? That seems unlikely meaning the ECU you're plotting will only ever work right with a custom harness so you're product maybe should be a proteus wiring harness for fox body mustangs? Plug and play only works on cars that have something useable to plug into right? Or find a later model harness you (or anyone) can easily modify and be p&p with that harness?
So the factory harness uses the TFI on the distributor to synchronize the ignition and injection, but no one has bothered to code this for rusEFI and if there's an option to upgrade to delete the distributor and go to wasted spark I'll take it!

I'm still planning on wiring it up physically in case someone wanted to mess with it though so there's no reason you couldn't use the stock harness and everything with the exception of the emissions crud and o2 sensors. But I'm adding additional features (such as the ignition) from originally unpopulated pins.

I agree, it might be better to just use the proteus, but this way lets me use the stock case and not worry about fabricating one and it looks completely stock and will be way easier for those who aren't good with electronics to do.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mck1117 »

wstefan20 wrote:
Tue Dec 29, 2020 10:12 pm
Also, I've heard rumors of wideband o2 controller onboard one of the boards. Is this something feasible? If not, I'm guessing most wideband o2 sensor controllers output 0-5V and I can just hook this up to one of the analog inputs?
There's a wideband controller under development here: https://rusefi.com/forum/viewtopic.php?f=4&t=1856 that could work inside the ECU, though it's just barely in to beta land with only one example ever hooked up to a real car. So eventually yes, but today probably not quite yet.

You have it right on an analog external controller though, you can just hook it up to an analog input. The AEM X-Series stuff is also supported over CAN and is much faster and more accurate than anything analog (no ground offset error!).
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mck1117 »

wstefan20 wrote:
Wed Dec 30, 2020 12:30 am
So the factory harness uses the TFI on the distributor to synchronize the ignition and injection, but no one has bothered to code this for rusEFI and if there's an option to upgrade to delete the distributor and go to wasted spark I'll take it!
What do the signals from the TFI look like? If it's just one tooth per cylinder from TFI -> ECU, and normal charge/fire signal from ECU -> TFI, then that'll work with zero software changes.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by wstefan20 »

mck1117 wrote:
Wed Dec 30, 2020 12:28 am
mk e is correct - the tach output is completely independent of fuel/ign, so you can actually run any number of pulses per rev (even fractional) on any engine.

VSS is very much not required, but does work if you want it wired to the ECU as well.
Awesome! Thank you for clarifying that! Just a few more things and I will post the revised diagram just to see if you guys see anything wrong.
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Re: 1986 Ford Mustang 5.0 EFI swap

Post by mk e »

wstefan20 wrote:
Wed Dec 30, 2020 12:30 am
mk e wrote:
Tue Dec 29, 2020 10:37 pm
So again, what exactly are you doing?
Sorry. I'm still getting used to the naming conventions. For ignition, my plan is to do waste spark but also populate extra pins so that I could switch to direct fire later.
Again, what is your plan for fuel, not spark, fuel?
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