[help needed] 1973 Chevy c20 5.7L SBC TBI conversion

[3gAccord]

Its alive!! Lots of 500 Internal server errors on the forum, btw! repeatedly refreshing fixes. Not sure what thats about....

Frankenso lives. the jumper rearrangement and replacing a 0ohm fixed it. The display is strange, however running of 12V i cant read it except from an angle.... If i power off just USB, its normal.. Strange... Very strange....

Anyways, tomorrow I'm hoping to do some initial testing... We'll see!!

[3gAccord]

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Everything is alive off 12v. Still need to connect IAC stepper coils, injectors (low Z maybe using a Honda injector resistor pack??), and hei module

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[kb1gtt]

Fingers crossed that the forum issue are resolved.

Good news and good pictures. For your IAC, see what I did on a similar application found here http://rusefi.com/forum/viewtopic.php?f=3&t=864 Hmmm, looks like id didn't post a picture of the A4988. I'll see if I can take a picture of that board.

[3gAccord]

Gahh. forum is still doing 500 errors. Lost my last post, so a short recap -- IAC stepper board is en route from Pololu (thanks kb1gtt for pointing out a seller!) and I'm going to try to find a Honda resistor pack for the injectors this evening. Do I just basically wire for example Inj 1 output w/ resistor + Inj 3 output w/o resistor => Injector 1 gnd, Inj 2 w/ res + inj 4 w/o res => Injector 2 gnd? then supply 12V+ via a relay (main relay?) through a fuse to the other side of the injectors??? Thanks!

[3gAccord]

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Denso resistor pack for injectors. Any black to another is 16ohms, red to any black is 10ohms. This work??

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[kb1gtt]

Sure why not

It's not really optimal and I'm sure there will be people who will comment it's not correct, but I think it will work good enough for now. I wouldn't consider it high performance or anything like that but it should work.

[3gAccord]

So how would I wire it? Ch#1 > resistor + ch#3 > no resistor > injector, same for other but 2/4?? Merry Christmas, BTW Jared!

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[kb1gtt]

I think you have the idea, but there is a need for some software to be developed before it can really be done. I should encourage getting the crank / cam decoder working.

[3gAccord]

That's fine I just need to finish this wiring so I can wrap it up and stuff Iy through the firewall I'll be getting the distributor interface going soon. Gonna be a long weekend but we're getting there.

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[Rhinoman]

You may need to use the resistor pack that goes with the injectors, if the resistance is too high then the injector opening and closing will be quite slow; Injectors that have resistors are usually a low inductance. It will depend on whether or not you can meet the minimum injector time for low loads, what vehicle is the Denso resistor pack from?

[3gAccord]

There doesn't seem to be a 'proper' resistor pack for this application.. It's from a Honda accord or prelude early 90s obd1, f22a1 or h23a1 engine. I believe a prelude 92, f22a1 but its a common Honda part for the era. I'm thinking it was internal to the GM ECU but I've no idea. This is a swap on a 73 carb engine using parts from 89-91 GM 5.7 TBI trucks. Got tired of carbs n had a Frankenso sitting idle

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[Rhinoman]

Did the GM ECU use a PWM drive?

[3gAccord]

No idea how it works. Couldn't use it on my engine due to the cam not being compatible.. It's late 80s technology. I'll see what my friend Google says

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[Rhinoman]

If its a peak-hold injector then I would expect it take need 3-4 Amps to open reliably. From what I understand from the post above you are putting 10 Ohms in series so you will get less than a amp while cranking.

[3gAccord]

Hmm. I could I wire a pair of resistors to get 5 ohm??? There's 4 injectors on the typical usage of these denso resistor packs

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[Rhinoman]

No harm in trying it. I know very little about the GM ECUS, The DIY-EFI mailing list used to be the place for GM ECU knowledge but unfortunately its been dead for some time now.

[3gAccord]

I'm using Frankenso.. No GM here lol

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[Rhinoman]

Yes but it helps to know how things are designed to work, it makes it easier when you're trying to use them in a different application. The Honda injectors will be designed to work with those resistor packs.

[Rhinoman]

Presumably your resistor pack is something like this one (from a Mazda RX8):



Your resistance measurements must be a little out, you should get 16 Ohms/8 Ohms or 20 Ohms/10 Ohms unless there is something else in the pack.

[3gAccord]

It is a Chinese meter....

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[3gAccord]

But yes I'm pretty sure we are on the same page. Doesn't Mazda use denso parts???

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[3gAccord]

I think I need to amazon some high quality USB cables with 90degree plugs. Having issues with console and TunerStudio when connected to the mini USB port. I'm not physically able to access microusb in the vehicle. May have to pull case off Frankenso and finish the hole for it

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[3gAccord]

Progress has been made!

I still need to get a different laptop for tuning (something with windows) or reinstall my Kubuntu as USB serial devices of all sort just simply do not even show up in dmesg or lsusb. Wideband O2 will be being ordered on 1/8. For now I've got everything except for IAC stepper driver and IAT connected. Most sensors seem to give reasonable values, the rest I'll doublecheck wiring. Unfortunately I don't get much time to work on things except for the weekends since it's always dark and rainy by the time I get off work in the evenings. As for crank signal, I'm going to disassemble the distributor sometime this week and see what we can't do about maybe removing a tooth from the wheel or something so we can get a TDC indication..... Any better suggestions? I'm not at all opposed to abandoning the HEI module if that's what has to happen, I just wanna get started playing with the code

Hope everyone had a great Christmas and has a pleasant new year! Thanks for all the help guys (and if we have them, gals!)

Cheers
- Gwar

[AndreyB]

and if we have them, gals!

Not that I am aware We need some gals!

The code is getting closer

[3gAccord]

Im hoping for new year to begin with the old truck running even poorly off fuel injection;)

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[3gAccord]

Just to verify -- i need to run channel 3 through one of these to left bank and channel 4 through one of these to right bank injector. As well I need tie channel 1 to the left bank injector and ch 2 to the right bank injector.

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[kb1gtt]

You a likely in the ball park, it claims 10W, but I'm sure that's going to be at a very high temperature, which could melt things. That's why the salvage yard one has a heat sink. The elevated temperatures will cause the wires to erode faster and such, but any how, it will probably work. I'm not sure if you would need 10 ohms or you might need something like 7 or 12. From where I stand with a blind fold on, it should work.

[3gAccord]

Fair enough. If it gets it up and running to where we can get something better in place, that's fine with me I just wanna hear the old beast run on its own powered by the Frankenso magic

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