Another e30 electrical problem thread

[StereoInstaller1]

Do NOT use a DMM to test fuses, get a testlight...one with an actual lightbulb.

Test fuses installed, as in powered up. Your testlight will show if the circuit has power too.

Testlights are superior to DMMs for testing simple electrical circuits like these, as a DMM can read "ghost voltage" and make you believe all is OK, while a testlight requires just a bit of current. Trust me on this!

Electrical issues = test light

Electronic issues = DMM

[white04wrx]

OK, first: what device are you using to test for power?

To test the power I am using a Mastech MS8222H multimeter. I know the multimeter works because it gets a reading when I test the battery. Would I be able to see the ground point you mentioned earlier if I look under either the drivers seat or passenger seat?

You may be barking up the wrong tree. As DaveSmed said earlier, the pump is only powered up when the DME sees timing data from a rotating engine. So you have to check for power to the pump while cranking the engine.

Is there spark when cranking?

Let me go ahead and test the voltage on the power supply leading into the fuel pump again while I have a buddy crank the engine.

[jlevie]

You may be barking up the wrong tree. As DaveSmed said earlier, the pump is only powered up when the DME sees timing data from a rotating engine. So you have to check for power to the pump while cranking the engine.

Is there spark when cranking?

[StereoInstaller1]

this wiring diagram is beyond my mental capacity. Haha. Can you in the most simply English possible, tell me exactly where I am able to locate this ground point in the car? Thanks so much.

OK, first: what device are you using to test for power?

[Bimmerista]

How long have you had this problem on the car? Are you still working on it periodically to figure out the problem?

Started happening last Wednesday. Due to my work schedule, I'm only able to check out in the evenings. And by then, I'm usually too out of it to work on it.

[white04wrx]

Depending on if you have an early (MY 1987 and older) or late model E30, you have two possible fuel pump arrangements. The older cars have an in-tank low pressure lift pump that supplies a high pressure external pump located under the car just in front of the drivers side rear wheel. If you suspect weather to be a factor, this pump and its associated wiring are hanging under the car in the elements.... The later cars have a more conventional single in-tank pump.

On the early cars, failure of the in-tank pump is becoming common at this age, and the added stress shortens the life of the external pump. On both early and late there is an access plate inside the car under the rear seat to remove the in-tank pump without dropping the tank.

Thanks for the informative information. The car is a 1984 325e. Does it still have two fuel pumps? In that case I checked the power supply on the fuel pump that is located in the back seat, passenger side under the black panel. Can the problem still be the actual fuel pump even though there is no power going into it?

Amazing...I'm having the SAME EXACT problem the OP is having with my car at the moment. I have yet to figure out the issue.

How long have you had this problem on the car? Are you still working on it periodically to figure out the problem?

To the OP: Do you have diagram reading skills? Go to www.wedophones.com and click on manuals, them automotive and download your "Electrical Troubleshooting Manual".

You will see that both fuel pumps share a single ground point, I believe the one under the seat (G300 anyone?) which is known for loosening...which might pop a fuse, as would a pump crapping out.

As Dave pointed out, fuse 11 runs ONLY the 2 fuel pumps.

GL on the hunt!

Luke

Thanks for the link. However this wiring diagram is beyond my mental capacity. Haha. Can you in the most simply English possible, tell me exactly where I am able to locate this ground point in the car? Thanks so much.

[StereoInstaller1]

To the OP: Do you have diagram reading skills? Go to www.wedophones.com and click on manuals, them automotive and download your "Electrical Troubleshooting Manual".

You will see that both fuel pumps share a single ground point, I believe the one under the seat (G300 anyone?) which is known for loosening...which might pop a fuse, as would a pump crapping out.

As Dave pointed out, fuse 11 runs ONLY the 2 fuel pumps.

GL on the hunt!

Luke

[DaveSmed]

oh dang it, i just read where it said that it strictly powers the fuel pump.

GO CHECK YOUR O2 SENSOR WIRING! I know that on Bosch systems that the O2 sensor wiring shorting out can kill the fuel pump fuse.
lemme know

Not in an E30.

[Sagaris]

oh dang it, i just read where it said that it strictly powers the fuel pump.

GO CHECK YOUR O2 SENSOR WIRING! I know that on Bosch systems that the O2 sensor wiring shorting out can kill the fuel pump fuse.
lemme know

[Bimmerista]

Amazing...I'm having the SAME EXACT problem the OP is having with my car at the moment. I have yet to figure out the issue.

[Sagaris]

Welcome! +1 on the proper post. Your profile lists that you have a 325e so I am assuming that is the car you are having issues with.
Edit: nevermind

[DaveSmed]

THE FINDINGS
I checked both fuel relay and main relay and those were working fine. I also looked through the fuse box and noticed fuse 11 (ignition electronic) was blown. I replaced that fuse and tried starting the car. It did not start and the fuse blew again. I put my last fuse I had on hand in there and tested the voltage on the power supply that feeds into the fuel pump while the car was in the on position. The voltmeter read 0.

Nice post with the breakdown! It's even recognizable as English! Harder and harder to come by from new members around these parts...

Anyway, on to the car. Fuse 11 strictly powers the fuel pump, and is fed power only when the engine is producing an RPM signal, causing the DME (Bosch for ECM by the way) to close the fuel pump relay. At all other times fuse 11 does not have power as it is downstream from this relay.

Your problems are consistent with fueling issues, so it is likely that the fuel pump is malfunctioning. These cars do not typically have odd harness issues (like VW) and are pretty straightforward when they break.

Depending on if you have an early (MY 1987 and older) or late model E30, you have two possible fuel pump arrangements. The older cars have an in-tank low pressure lift pump that supplies a high pressure external pump located under the car just in front of the drivers side rear wheel. If you suspect weather to be a factor, this pump and its associated wiring are hanging under the car in the elements.... The later cars have a more conventional single in-tank pump.

On the early cars, failure of the in-tank pump is becoming common at this age, and the added stress shortens the life of the external pump. On both early and late there is an access plate inside the car under the rear seat to remove the in-tank pump without dropping the tank.

[white04wrx]

THE INTRODUCTION
Hey everybody, just wanted to introduce myself to the e30 community. Just picked up my first Euro after driving Japanese cars all my life. I picked this car up to be used as a daily driver so I would not rack up miles on the wrx. As of now I must say, what a bittersweet experience thus far.


THE SYNOPSIS
After having it for about 2 months, I had it sit outside because of the raining and I didnt trust the tires on the car. After 3 days of rain, I went to start it up and it had a little more difficulty starting then it normally would. After about the third crank, it started up and I was on my way around town to run some errands. About 5 minutes later the car seemed to be acting abnormally. It would have barely any power when the gas pedal was pressed and I was creeping through the intersection (car almost died on the way). After that I knew something was wrong so I pulled over into a parking lot and observed the abnormal idling of the engine. I knew something was wrong so called my friend for a tow. After getting towed to my friends lot, I tried starting the car up just to see what happened and it started right up. I test drove it around the block with no worries. I got back to my friends lot to tell him I think I was going to drive it home. I tried starting again and it started up and when I gave it a little rev, no power and it died.


THE FINDINGS
I checked both fuel relay and main relay and those were working fine. I also looked through the fuse box and noticed fuse 11 (ignition electronic) was blown. I replaced that fuse and tried starting the car. It did not start and the fuse blew again. I put my last fuse I had on hand in there and tested the voltage on the power supply that feeds into the fuel pump while the car was in the on position. The voltmeter read 0.


CONCLUSION AND A PLEE FOR HELP
My conclusion is that the fuel pump is probably working fine but because there is no current going into the pump, there is no fuel going into the engine. This would explain the abnormal idling and the lack of power that the engine supplied. Also there might be a short in the wiring somewhere since I keep on popping fuses. Every time I turn the key, the engine cranks over but does not completely start. As of now the car is sitting at my friends lot with no hope of coming back to life. I recently named this car Michael Jackson because if it does not start soon, THIS IS IT!!


Any educated recommendations or procedures that I should perform to bring this car to life or solve this short in the wiring? Is this a major problem with Euros where at this point it would be smarter off to cut my losses and move on to another project?


PS – sorry for the long write up but I wanted to be as thorough as possible regarding all aspects of this situation. Thanks for your time.