87 ETA: Cranks, Fires, Stalls!

[BonnschE30]

Hey guys, just looking for a little assistance in getting a recently purchased 87 325E up and driving.


Here's what's going on:

• I can get the car to crank, the rpms rise, it finally fires, runs for about literally 1-2 seconds, then falls flat and dies immediately.

Here's what i know:

• Fuel pressure during cranking is ~38psi
• AFM, Fuel Pump Relay, Main Relay from my other running '87 ETA were swapped in to no avail.
• Jumped the fuel pump relay #30/87, can't tell if in-tank pump is running or not
• External pump looks new and buzz is quite audible

I'm thinking in-tank pump might have bitten the dust, but how can I check to see if it has indefinately crapped out of service? I'm not too familiar with how the fuel system operates...

Some other ideas I've gained from searching have been CPS and Coolant Temp Sensor, but I'm thinking its fuel. Could this be a filter issue? Anyway to check without replacing it?

BTW I have a chinsy multimeter but i'm not too familiar with using it. And no Bentley either...

Any advice on how to be certain if my in-tank pump is working or not would be much appreciated. I think I'm going to pull it tomorrow to see how much gunk might've accumulated. Thanks in advance for any helpful and prompt replies!

[jlevie]

The fuel pressure is sufficient for the engine to run, so that's not the cause. Check for intake leaks.

[BonnschE30]

Thanks J, I was hoping for a reply from you.

I've done visual checks for vacuum leaks, originally I found this intake boot to be torn and rigged with electrical tape, so I used the good one from my daily driver and still the same result.

Everything looks good as far as hoses, etc go. Maybe my intake manifold gasket is shot? Could my return line from FPR possibly be clogged?

I'll keep looking for leaks...

[TopOfTheLine89]

My fuel pressure was went 50 one crank, then shot up to 100psi after second crank, i bet your pump is gone and just enough pressure is built up to run it for a second. i could be totally wrong though.

[BonnschE30]

The fuel pressure is 38psi during initial cranking, and once the motor fires it drops to around ~30psi, then dies right away.

I pulled the in-tank pump and it looked like a wire was missing from one side of it, going from one of the 'coils' (for lack of a better word) to what looked to be a ground. Any pictures of fuel pump wiring?

I might take my known working one from my daily driver 325E and transplant it to see if there's any changes.

Thanks for the responses so far.

[BonnschE30]

Ok so I swapped a known working in-tank fuel pump from my daily driver and the car still does the exact same thing. So fuel pump is not the issue here.

Also still looking for a vacuum leak, any ideas or known problem areas? Everything around the intake manifold looks good with no split hoses, loose clamps, or anything.

I want to test my coolant temp. sensor and crank sensor. Anyone familiar with the process or the in-spec values?

This is starting to become a royal PITA and there might be lots and lots of ETA parts up for sale soon...

[qbuilt]

Have you checked your Idle switch. Located on the bottom of the throttle body. Can you hear it click when you slightly open the Throttle linkage by hand?? Also try leaving the AFM unplugged and see if you can get it to run while keeping your foot on the gas. Really the only things that would cause a M20 not to start would be the crank reference sensor(located on bellhousing of trans), No fuel, or way to much(car could be flooded due to a bad AFM signal, pull the plugs and see if they are wet), Bad ecu. Also a massive vacuum leak, but that should not be hard to find. Even with a relatively large leak the car should still start, just wont idle. The fact that the car starts then dies makes me think that the crank reference signal is good. If it wasnt, there would be no spark and the car would not start.
Good luck

[BonnschE30]

I checked the switch you're talking about awhile ago, it was very oily upon inspection then. I used some contact cleaner on it. But there is an audible click when opening the throttle body slowly by hand.

I'm not sure what to look for anymore... I peered in the tank a little more closely and its looking like there is alot more rust in there than I originally thought. So I'm GUESSING that could be a major part of the problem.

Regardless, my daily driver is acting up now that I put its "good" fuel pump back in after testing on this problematic car. So in essence I've sabotaged a great running car in attempt to fix this "won't stay running" problem. With that being said, I think the problem car is getting parted out and with the remains headed to the scrap yard. What a shame because the exterior really isn't all THAT bad...

[bioman]

Check the spark plugs and ICV. But, sounds like you have a vacuum leak to me. Spray down every hose and gasket area with a fine mist of water and see if it's bubbling anywhere when the car is running.

[BonnschE30]

ICV checked out okay with 9.0ohms. All the injectors were at 2.4ohms. I'm still looking for any vacuum leaks but car won't stay running long enough to get any idea of where a leak could be.

Frustrating as hell!

[Knockenwelle]

Sounds like a fuel starvation issue. Are you sure the fuel lines at the regulator aren't switched?

[BonnschE30]

No the fuel lines are correct, but that being said I think its a probably strictly a fuel issue too. I've used good pumps and a good FPR, only thing I haven't tried is the filter. And I'm not about to even put $10 in guessing a fix at this point. I'm disturbed by the amount of rust I've found in the tank, and I'm almost positive that it at least partly, if not all to blame for my problem. But regardless, I'm going to part the car so if anybody wants a complete 5 speed conversion let me know! I'll make a FS thread soon...

Thanks for the insight guys, I really appreciate all of your thoughts and advice in helping me out!