Starts then stalls

[DesertEagle]

Hey,

I have a 1991 318is.  The car starts fine, but stalls out in a few seconds unless I use the accelerator.  It runs well at 1200 rpm or higher, but it gets rough below that.  After the car reaches operating temp, it will maintain idle, but its very choppy.  There are droplets coming out of the exhaust.  It's water, not gas.

The ICV, O2 sensor, and AFM are new.  All four plugs, which were new, are fouled.  I decided to check the fuel pressure by jumping the fuel pump relay with the ignition off.  The pressure gauge is connected with a T-fitting between the inlet fuel hose and fuel rail.  I got 48 psi.  20 minutes after I stop the fuel pump, the fuel pressure drops to 36 psi.  Haynes, Chilton's, and both Bentley's are jerking me around as to what the fuel pressure should be, so I don't know if these readings are kosher.

Can you help me interpret these results and suggest where I go from here?  Thanks!

[vibefm]

:(Hi,

I have a 1993 318is that has the same type of fault but goes the other way, idles fine at 900rpm and runs great no misfire or anything, but get this it gets stuck at 2000rpm when warm and wont return back to 900rpm until you rev it hard. I have had everything checked ICV, EMU, Wiring loom, throttle linkage, and had it plugged into a computer to read any error codes... and you can guess the rest it found nothing to show what was going on?

Has anyone else come across this - engine sticking when warm at 2000rpm

please reply to this post or email me jgadd01@btinternet.com

[RED IS 91]

You should have 42-43 psi when checking at the pump under the rear seat.Tee your gauge in at the supply side of the pump and start your engine.Although I think that 48 may not be bad I believe the bentley tells you to check at the pump.

[DesertEagle]

You should have 42-43 psi when checking at the pump under the rear seat.Tee your gauge in at the supply side of the pump and start your engine.Although I think that 48 may not be bad I believe the bentley tells you to check at the pump.

While the ultimate goal is to have the correct fuel pressure while the engine is running, it is not the most useful test from a troubleshooting perspective.  Right now, I'm trying to isolate variables so they can be tested.

I've heard that fuel injectors "sticking" open even 10% longer is a problem because it enriches the air/fuel ratio.  I've read that the e30 m42 uses a 3.0 bar system, which is 43.5 psi.  If the fuel pressure is 10% higher, then that's 10% more fuel injected every time an injector opens.  10% of 43.5 psi is 4.35 psi.  43.5 + 4.35 is 47.85 psi.  By that logic, 48 psi would be a problem.  But the bigger problem is I don't know how to interpret my fuel system pressure test.

Where are this forums big guns when you need them?

[RED IS 91]

While the ultimate goal is to have the correct fuel pressure while the engine is running, it is not the most useful test from a troubleshooting perspective.  Right now, I'm trying to isolate variables so they can be tested.

I've heard that fuel injectors "sticking" open even 10% longer is a problem because it enriches the air/fuel ratio.  I've read that the e30 m42 uses a 3.0 bar system, which is 43.5 psi.  If the fuel pressure is 10% higher, then that's 10% more fuel injected every time an injector opens.  10% of 43.5 psi is 4.35 psi.  43.5 + 4.35 is 47.85 psi.  By that logic, 48 psi would be a problem.  But the bigger problem is I don't know how to interpret my fuel system pressure test.

Where are this forums big guns when you need them?

It would be a problem if your injectors were sticking open.Why don't you test it where I suggested and see what the results are .The car does not need to be running but is a better test.There is also a flow test that is in the bentley manual that you can do.Here's a diagram that shows the system.Maybe your gauge is off ,did you think of that?
I'm done helping ,obviously your a lot smarter than I am.

[DesertEagle]

I tested the fuel pressure on the fuel pump side while the engine was running from 800 rpm to 2,000 RPM.  The pressure was constant between 38-40 psi.  Is the about right?

Red, I didn't mean to offend you.  I checked the Bentley and it says to use a T-fitting at the supply side of the fuel rail.

[Ryann]

Hey,

I have a 1991 318is.  The car starts fine, but stalls out in a few seconds unless I use the accelerator.  It runs well at 1200 rpm or higher, but it gets rough below that.  After the car reaches operating temp, it will maintain idle, but its very choppy.  There are droplets coming out of the exhaust.  It's water, not gas.

Based on these symptoms the last thing I'd be checking is fuel pressure at the pump. Air filter? Timing?