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Re: 1998 BMW V12 engine M73 #55

Posted: Mon Nov 30, 2020 4:14 am
by kb1gtt
These are snippets found in the below link. Of course if they said it on the internet, it must be true.
https://www.theglobeandmail.com/globe-drive/culture/commentary/the-problem-with-ethanol-in-gasoline/article29103634/
Because it is an alcohol, ethanol dries out the rubber components in a fuel system. This leads to cracking and brittle fuel lines, floats, seals and diaphragms.
Other studies have shown that automobile engines produced prior to 2007 showed damage to valves, valve seats, seals, hoses and other components.

Re: 1998 BMW V12 engine M73 #55

Posted: Mon Nov 30, 2020 12:17 pm
by mk e
Its not untrue, but at 10% or 15% they are talking about small changes in life expectancy....E85% would be a different story.

As a rule, anything "rubber", and there are countless varieties, that is over 10 years old is suspect. At 20-30 most rubber items are staring to crumble....its happens faster in the sun or around different chemicals depending on the specific rubber and the amount of heat it sees.....if I recall this is an older high mileage engine, which means hours and hours of heat time and thousands of heat cycles but the kiss of death was probably the time it now spends cold and sitting....probably not a coincidence it started leaking when the weather turned cold, those o-rings are probably hard as rocks and will just crack when you try to get them off. 150k miles or 15 years and most gaskets and seals are on borrowed time....its just time.

Re: 1998 BMW V12 engine M73 #55

Posted: Wed Dec 09, 2020 4:32 pm
by AndreyB

Re: 1998 BMW V12 engine M73 #55

Posted: Thu Dec 10, 2020 4:55 am
by Lambo97
I'm not sure if I missed somewhere in your thread here. What MAP sensor did you use on your motor and is easily connected to the proteus? My guess is a 1 Bar GM standard Map sensor? the LS1 has a nice small unit like this:
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Or did you go more traditional with this guy:
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Re: 1998 BMW V12 engine M73 #55

Posted: Thu Dec 10, 2020 5:09 am
by AndreyB
i have horrible news for you. I run based on throttle, which is good enough for parked engine idling. you want to install any MAP or even OEM MAF but just tell us where and how.

Re: 1998 BMW V12 engine M73 #55

Posted: Fri Dec 11, 2020 7:48 pm
by bill
i have a bosch MAP and inlet temp sensor. i grabbed off a VW in junkyard. will mount it into a hole in the manifold soon...
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Re: 1998 BMW V12 engine M73 #55

Posted: Sat Dec 12, 2020 12:31 am
by AndreyB
Many lines, I have no idea which one does what.

My goal is to install a MAP sensor with minimal efforts, it would also be nice to remove some parts to make things nicer.


Re: 1998 BMW V12 engine M73 #55

Posted: Sat Dec 12, 2020 2:22 am
by mck1117

Re: 1998 BMW V12 engine M73 #55

Posted: Sat Dec 12, 2020 2:46 am
by AndreyB
I am confused by this red air path - it looks like one side goes into MAF<>ETB hose before ETB, and another side of the red path goes into intake manifold after ETB? How is that a thing? Unless there is one way valve somewhere?

Re: 1998 BMW V12 engine M73 #55

Posted: Sat Dec 12, 2020 5:14 am
by AndreyB
How often do you hear "let me epoxy air intake on my injector"?

Re: 1998 BMW V12 engine M73 #55

Posted: Sat Dec 12, 2020 12:29 pm
by mk e
AndreyB wrote:
Sat Dec 12, 2020 2:46 am
I am confused by this red air path - it looks like one side goes into MAF<>ETB hose before ETB, and another side of the red path goes into intake manifold after ETB? How is that a thing? Unless there is one way valve somewhere?
It looks like they are just tapping opposite ends of the manifold....if they use the same casting on both sides the ports would end up at opposite ends.

The line going to the TB is confusing but I suspect its some kind of vacuum assist or pressure reference or something like that vs a port into the air flow.

Those injectors look like they understood the short pulse fuel flow depends on deltaP but didn't have ECU memory and/or processor time for more tables so they built a mechanical solution.....maybe time to retire those or ask the lambo guy who's retiring his to send them to you?

Re: 1998 BMW V12 engine M73 #55

Posted: Sun Dec 13, 2020 1:45 am
by AndreyB
24 hours under table lamp to make sure it's well done.

Re: 1998 BMW V12 engine M73 #55

Posted: Sun Dec 13, 2020 2:00 am
by mk e
Where's the barb? no barb will change the effective deadtime compared to the others unless you just unplug them all

....and I'll be honest, that glue does not look bondes....it might be but it sure looks like its already delaminating at the edges. for probably 15 years now, I've had the words "glue is the devil" written across the top of the white board in my office....it always seems easy but it almost never is.

I think you pop the epoxy off, and I think it will just pop off, then unplug the rest from vacuum and call it fixed !

Re: 1998 BMW V12 engine M73 #55

Posted: Tue Dec 15, 2020 4:58 am
by AndreyB
TL,DR: all 50 psi now stay in the engine.

I am not planning to control air injection system so I assume it does nothing. I've plugged #12 nipple on the air rail. #12 is the one with epoxy fix and without injector metal lock since I've lost one. Injector #12 is the most accessible injector on this vehicle, hopefully one day I will remember to grab that little metal thingy and put it back on.

I've crushed new o-ring on injector #2 and it was leaking. Then I've crashed one the brown o-rings which I have no idea why are included in the replacement set - I've used two black o-rings per injector while set has two black and one brown. Just not much luck with #2. I've picked the best looking used o-ring from the trash and #2 is no longer leaking.

Obviously one of the hosts I was twisting developed a tiny leak and gave me an amazing thinnest possible spray of fuel. New clamp has addressed that. I've dried the engine of fuel and tested for a few minutes, looks good. Tomorrow will run fuel in in for 20 minutes just to be sure.

Re: 1998 BMW V12 engine M73 #55

Posted: Tue Dec 15, 2020 9:29 pm
by bill
remove all those worm drive clamps on the fuel lines.... left over from the previous dude... make your life better... they will leak sooner or later...

Re: 1998 BMW V12 engine M73 #55

Posted: Tue Dec 15, 2020 10:20 pm
by mk e
And next time if you didn't this time, lube the o-rings with oil, wd-40, anything really, it makes a difference trying to put them together...and yes, I learned that lesson by destroying o-rings so I understand the pain.

The air rail you're talking about are the vacuum hoes connecting to the injectors? There is nothing to control is there? Looking at the pics and vacuum diagram you posted I thought they were just vacuum lines to keep the pressure across the injector constant regardless of manifold pressure to keep deadtime constant, a mechanical version of the deadtime tables modern ECUs use.

Just make sure you plug any open vacuum lines....you could plug of them with with a MAP sensor :)

Do you have a baro sensor? That is pretty important if you stick with alpha-n tuning. Not as important if you switch to speed-density but still useful to separate driver's intent from weather or elevation changes, this can also be pulled from TPS but its easier with baro.

Re: 1998 BMW V12 engine M73 #55

Posted: Tue Dec 15, 2020 10:25 pm
by mck1117
mk e wrote:
Tue Dec 15, 2020 10:20 pm
And next time if you didn't this time, lube the o-rings with oil, wd-40, anything really, it makes a difference trying to put them together...and yes, I learned that lesson by destroying o-rings so I understand the pain.
vaseline or silicone lube is best

Re: 1998 BMW V12 engine M73 #55

Posted: Tue Dec 15, 2020 10:34 pm
by AndreyB
mk e wrote:
Tue Dec 15, 2020 10:20 pm
The air rail you're talking about are the vacuum hoes connecting to the injectors? There is nothing to control is there?
"#5 air shut-off valve" seems be in control of the vacuum line between intake and injector air rail?

Re: 1998 BMW V12 engine M73 #55

Posted: Tue Dec 15, 2020 11:16 pm
by mk e
AndreyB wrote:
Tue Dec 15, 2020 10:34 pm

"#5 air shut-off valve" seems be in control of the vacuum line between intake and injector air rail?
Ok, looking closer there is a valve.....are the fuel injectors plugged into that same rail? and its plugged into the exhaust?

Re: 1998 BMW V12 engine M73 #55

Posted: Wed Dec 16, 2020 1:17 am
by Simon@FutureProof
Might be able to clear up some confusion here, the injectors are "air guided" so they use a cushion of air around the injection spray to help prevent port wall wetting (and thus emissions during transients), I believe they are not using any kind of pressurised air unless they were previously connected to the secondary air pump that provided air into the catalysts for smog legislation purposes.

You can safely leave that system off and not really have any running issues on RE.

Regarding your MAP sensor, I am assuming you want to put on onto a hose for minimal effort, if so then take off the pipe leading to the brake booster at around 1:55 in the video and use it to plug the MAP into, should read fine there.

The plastic piped that go into the MAF I believe are EVAP canister pipes, the valves allow the ECU to open a vent to the fuel tank under certain loads to help reduce evaporative emissions from the fuel tank. You can delete those with RE.

TLDR you can throw away a huge amount of the stock vac system with RE.

Re: 1998 BMW V12 engine M73 #55

Posted: Wed Dec 16, 2020 1:25 am
by Simon@FutureProof

Re: 1998 BMW V12 engine M73 #55

Posted: Wed Dec 16, 2020 11:18 am
by mk e
OrchardPerformance wrote:
Wed Dec 16, 2020 1:17 am
Might be able to clear up some confusion here, the injectors are "air guided" so they use a cushion of air around the injection spray to help prevent port wall wetting (and thus emissions during transients),
I would never have guessed they were feeding air through the fuel injector from the pics....never....I thought it was something way more clever and couldn't figure out how exactly they got it work.

Re: 1998 BMW V12 engine M73 #55

Posted: Fri Dec 18, 2020 1:00 am
by bill
i just pretend i am hooking up SU Carbys or DCOE ... and anything not needed by SU carbs is Dead Weight... to be jettisoned ...

Re: 1998 BMW V12 engine M73 #55

Posted: Fri Dec 18, 2020 7:02 pm
by Lambo97
mck1117 wrote:
Tue Dec 15, 2020 10:25 pm
vaseline or silicone lube is best
That's all I use, are we talking about engines?

I went with the GM MAP sensor. Andrey if you need some injectors shoot me your address in PM.

Finally I ordered new temp sensors just want to know if these are good to go to use with the proteus / rusefi? 2 pole ground and a resistance output. Andrey is rusEFI configurable to the resistance of the sensor or is that a hardware/firmware thing?
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Re: 1998 BMW V12 engine M73 #55

Posted: Fri Dec 18, 2020 7:09 pm
by AndreyB
rusEFI is configurable. Proteus probably has 2.7K pull-up so your sensor has to be in the reasonable range for that 2.7K pull-up. More details totally not on my vehicle thread :)

Re: 1998 BMW V12 engine M73 #55

Posted: Thu Dec 24, 2020 9:53 pm
by AndreyB
Weight reduction: air injection rails capped & related valves removed, also vacuum canister from another air system removed.

Re: 1998 BMW V12 engine M73 #55

Posted: Sun Feb 28, 2021 1:16 am
by AndreyB
Just moved my v12 to the new house! Moving the v12 is quite a major milestone of my overall house move :)

Re: 1998 BMW V12 engine M73 #55

Posted: Sat Mar 06, 2021 4:30 pm
by JRockland
I never tough I would just randomly found a video about a successfull M73 build on an after market ecu !!!
I have a m73 Im slowly working on (well I havent touch it in a year..) because the only ecu I could afford was the Black emu, and I needed 2, and it was super expensive, and they dont have a base map for the m73.. And I dont know what im doing XD

I cant believe I found more people working on that engine !

My plan is to swap the ignition system for direct ignition (from m62b44 engines)
Swap the valves/springs for motorcycle high rev kit (trying to get the rev up to 7500)
Match it with a jaguar top mount supercharger (I machine parts so that gona be the easy part.)

I was stuck at the Ecu as obviously the stock one wouldnt do and I couldnt find any base map on aftermarket kit.. contacted multiple company and nobody have those.

So this morning I randomly found your video on youtube, I will go trough all the information and see if the option would work with my project.

So a big thank for the video, might have revived that project.
Also Im french so sorry for my english. :lol:

Re: 1998 BMW V12 engine M73 #55

Posted: Sun Mar 07, 2021 7:34 pm
by bill
send some pics!!

Re: 1998 BMW V12 engine M73 #55

Posted: Tue Sep 21, 2021 3:02 am
by AndreyB
https://github.com/rusefi/proteus-m73tu-adapter would be a way to connect Proteus to M73 much much easier that before.