Car starts and dies about 2 seconds later

[Batz]

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[LounsRacingInc]

I would just grab a wiring diagram, back probe your DME and see what input loses its signal when it dies. Also check your power/grounds to the DME to make sure they are consistent. Unfortunately, this method is a long frustrating one.

[nando]

if you are using i electronics, there's no "cold start valve".

A bad ICV can cause this as well, or a misadjusted TPS (doesn't enter idle mode). Does the ICV hum while the ignition is on? it runs at 90hz. You can also take it out and see if the solenoid moves freely inside the valve.

also check the function and adjustment of the TPS. If it starts and runs fine if you keep the throttle open manually, my bet is the ICV isn't working or it's not going into idle mode properly.

[Batz]

Thats the problem, even when i do give it gas it still runs pretty bad. Kind of sounds like an air leak somewhere.
How do i adjust the TPS? Or is the only way to do that is to buy a new one?
Also tomorrow ill borrow my friends ICV, AFM, and ECU to see if any of the are the ones causing this. So far it looks like its a bad AFM, but will see tomorrow for sure. At least will rule out some things if none of them help. Will keep you all updated.

[Bimmerboy91]

To me it sounds like electric or ecu related. Swap out the ecu see if it makes a difference.

[nando]

If it doesn't run right with throttle, then it's likely not the ICV (it's a little hard to tell with your descriptions).

are you using the 325i FPR? I don't know if the seta uses a 2.5 bar regulator like the eta did, but the 325i electronics definitely require a 3 bar regulator - it's clearly marked on it. also, did you swap to the 325i fuel injectors? If the injectors and FPR are wrong, it will not run correctly with the 325i computer.

Second thought would be the AFM. it could definitely be bad, the wiper/track can wear out after a while. there's a Porsche site that details how you can fix it but I'd swap in your friends first. You can sort of test the resistance of the wiper track with a multimeter, but that doesn't tell you much. You actually have to power it up and test the output voltage, not the resistance.

Another potential issue could be the coolant temp sensor (not the one for the gage, the blue one). If it's bad or the connector is corroded, that will seriously screw up the fueling to the DME.

DMEs do go bad but that would be pretty rare. We need Jlevie in here, he's like a human manual for M20 diagnostics.. I'm sure the first thing he'd tell you is to smoke test it, but since you're frankensteining parts here you need to make sure you're using the right assortment of 325i parts first. :)

[nando]

damn. I was looking for that Porsche site, and I learned that it has closed down. That's too bad - it had a lot of great info that was applicable to the E30. The internet archive has a copy fortunately. it looks like the AFM testing stuff is still there.

https://web.archive.org/web/20120415134702/http://www.the944.com/

[Batz]

nado thanks for trying to help, appreciate it a lot.

Anyways, i did get my friends ECU, ICV, and AFM and the car still ran bad, just like it did with all my parts. So we can rule those things out.
I did have a 2.5 bar FPR but i went to car quest, bought a new one for '89 325i so i guess its the 3.0. installed it and the car ran the same as before - bad.
Now i do have ETA injectors, didnt think they are any different so i didnt change them.
Do you guys think injectors might cause this? The car struggling to run and then dying i mean.

I let the car run for as long as it could, it ran for about a minute but then it started to slowly die. (RPMs would get lower and lower, car would get quieter) and then at the end it died after all...

Thanks for input.

[nando]

yeah, eta injectors are definitely different than 325i injectors - even the '88 seta. I don't think they are low impedance but they have a different part number. And yes, that will make the car run very poorly!

325i - 13641731357
'88 325 - 13641706414

I'm willing to bet the '88 325e injectors are 19# high impedance. stock 325i injectors are only ~14.5#.

[Batz]

I have injectors from an '88 325e.
Will this work? http://www.iemotorsport.com/bmw/E30-...yellowinj.html
or should i just get rebuild 325i injectors from catuned?

Eh... really not looking to changing them.

[nando]

I would just get 325i injectors unless you're going to get a tune for it.

it's not that bad. all you really need to remove is the valve cover. the plastic injector harness just pops off the injectors (pull up parallel in the direction of the injectors). There's only a few M10 bolts holding the fuel rail and the clips are easy to get off. Pull the fuel pump relay and turn it over until it dies. There will still be some pressure in the lines but it shouldn't explode in your face.

[Batz]

I was going to get a tune anyways to make sure everything runs nice with the cam while i am NA, but probably will just get the 325i, just to stay safe. Well, will see how it will be when i get them. Hopefully thats the problem.

Yeah, got bunch of gas in my eyes while changing the FPR, didnt think about it haha thanks.

[Batz]

Update.

Swapped in the injectors in today, rebuild 325i injectors from catuned. Car works perfectly fine now. Idles properly and doesnt do weird crap when giving it gas. Guess one of the old injectors wasn't working.

Thanks a lot for help everybody. Car should be on the road very soon, finally.

[downforce22]

I was going to say you have to use high impedance injectors from the 325i, as the low impedance injectors do not work but you figured it out.

Also, I found these two links on AFM rebuilds for future reference.

http://www.kamikazeracing.org/dl/JsAFMRebuild/

http://www.ericthecarguy.com/kunena/common-problems-pattern-failures/51691-bosch-air-flow-meter-check-clean-fiddle