S50 running issues

[Danny]

Everyone else is stumped too huh?

[e30rapidic]

does your CEL work for a stomp test? ECU swap?

[328ijunkie]

You replaced your fuel pump. You reuse the original pressure line in the tank? Pull the level sender out with the pump on and see if fuel is spraying everywhere.

[Danny]

The stomp test works but the whole time I haven't thrown any codes, so it wouldn't show anything. Haven't tried an ecu swap with the current issue. I have tried one when the no start issue was present.

[Danny]

You replaced your fuel pump. You reuse the original pressure line in the tank? Pull the level sender out with the pump on and see if fuel is spraying everywhere.

Nope. I replaced all the soft lines with new fuel injection line.

[328ijunkie]

Doesnt mean its not leaking. Had this issue with a swap customer a few years ago. Only had ~35psi of fuel presssure at idle. Fuel line in tank from pump to bracket was leaking.

[Danny]

Doesnt mean its not leaking. Had this issue with a swap customer a few years ago. Only had ~35psi of fuel presssure at idle. Fuel line in tank from pump to bracket was leaking.

Will double check that tonight. Going to replace the fuel pump connector per FredK's suggestion.

[10Toes]

Never had a FPR go bad... like ever...
Your flooding out the motor big time if you dont have a chip for the 21.5's.
17's to 21's is a big jump and the OBD1 electronics will never be able to compensate for that.

And by the vid. You have a Vac leak. The RPMs drop when you open the throttle not rise immediately.

My 2.8 ran fine with 21.5 lbs injectors and a OBDI with stock M50b25 tune. AFR's were perfect and it had no problems getting 30 MPG. Yeah I'm sure it would of made a little more power with a proper tune, it was probably still within 95% of possible power.

My OBDI electronics must be a freak of nature because OBDI sucks sooo bad.

[gazellebeigem3]

My 2.8 ran fine with 21.5 lbs injectors and a OBDI with stock M50b25 tune. AFR's were perfect and it had no problems getting 30 MPG. Yeah I'm sure it would of made a little more power with a proper tune, it was probably still within 95% of possible power.

My OBDI electronics must be a freak of nature because OBDI sucks sooo bad.

Agreed. I have also seen *gasp* fuel pressure regulators fail with my own eyes!!! 328icockjunkie appears to full of excellent advice today.

Danny if you're not setting any faults, I would run it with a fuel pressure gauge on it and go onto leakdown/compression from there if that didn't discover the problem. If that were caused by a vacuum leak, I think that the hiss at idle would be so noticeable that a supple young man such as yourself would hear it and quickly find a fucked connection or a cracked manifold.

[Danny]

Agreed. I have also seen *gasp* fuel pressure regulators fail with my own eyes!!! 328icockjunkie appears to full of excellent advice today.

Danny if you're not setting any faults, I would run it with a fuel pressure gauge on it and go onto leakdown/compression from there if that didn't discover the problem. If that were caused by a vacuum leak, I think that the hiss at idle would be so noticeable that a supple young man such as yourself would hear it and quickly find a fucked connection or a cracked manifold.

I do indeed hear a hiss at idle, having replaced all the vacuum connections and lines, my woman's intuition tells me I may have a bad manifold.

[328ijunkie]

Agreed. I have also seen *gasp* fuel pressure regulators fail with my own eyes!!! 328icockjunkie appears to full of excellent advice today.

Danny if you're not setting any faults, I would run it with a fuel pressure gauge on it and go onto leakdown/compression from there if that didn't discover the problem. If that were caused by a vacuum leak, I think that the hiss at idle would be so noticeable that a supple young man such as yourself would hear it and quickly find a fucked connection or a cracked manifold.

Not sure what i did to piss you off but feel free to PM me to holler at me for whatever beef you have with me.

Humbly speaking i do this for a living and have ALOT of experience with these engines and troubleshooting issues with them. I am by no means 'the expert' and have not seen every situation or problem possible. Did i say it wasnt the FPR? No i said 'Ive never seen it' meaning its uncommon, not impossible. And by the way i was already correct once that he had the wrong main manifold connector to be fair.
And if you heard the video you can clearly hear a vac leak. :P


As far as OBD1 'Faults' Go: The only code youll get if youre lucky if its a vac leak or a Fuel pressure issue is a MAF code.

[328ijunkie]

My 2.8 ran fine with 21.5 lbs injectors and a OBDI with stock M50b25 tune. AFR's were perfect and it had no problems getting 30 MPG. Yeah I'm sure it would of made a little more power with a proper tune, it was probably still within 95% of possible power.

My OBDI electronics must be a freak of nature because OBDI sucks sooo bad.

As i told the OP (on the phone, using my shop time to help a fellow R3v'er). The injectors are not his current problem. The car will run and drive fine for the most part with bigger injectors. Just like all the M20 guys going to 19lb injectors on the "2.7i"s. I said specifically his problem from what i could tell is a vac leak. That doesnt mean the car will be running well running too much fuel like that.


And what did i do to piss the world off this week? Trying to help?.

[e30user]

If there's a noticeable sound, wouldn't the ol' spray-stuff-with-carb-cleaner trick work? I'm actually curious about this. I'm still learning stuff, so this thread has been interesting. Have you done it since doing the most recent intake/vacuum related adjustments?

[Danny]

I did do the spray test with no obvious results.

Also, I appreciate all the help, sarcastic or not.

[Danny]

Okay, update time.

Changed the fuel pump connector, much more solid now but no change in the way it runs.

Pretty sure I have a small vacuum leak from my brake booster, I ordered a new grommet today and it should be at work tomorrow. Pulled the vacuum line from the FPR and it runs the same with the line plugged or unplugged. I removed the fuel line and when it drained, the fuel would only drain from the side opposite the FPR, and none out of the FPR side. Thoughts?