Fuel pump problems??? Help please...

[sctrini]

I have been having a lot of problems as in thread http://forums.bimmerforums.com/forum/showthread.php?t=1049182. My car would not start.

I checked the car out...I'm getting spark. But I thought this morning that I I heard the fuel pump but I was wrong. I listened really good but I can hear nothing like a fuel pump. Am I supposed to hear it clicking if the pump is working right? And should I get a CEL for a fuel pump if that is the problem?

All the fuses are OK. The engine turns over but will not start. Please help!!

[Phillips0417]

Sounds like a fuel delivery problem. You'll get no CEL on the fuel pump. It's fuel delivery, the CEL is emissions related components; ie-MAF sensor, O2 Sensors, etc...Disconnect your fuel line and turn on the key, although exercise caution because if your pump is okay, there will be a lot of fuel coming from that hose so be prepared..

[kevinqjhps]

Sounds like a fuel delivery problem. You'll get no CEL on the fuel pump. It's fuel delivery, the CEL is emissions related components; ie-MAF sensor, O2 Sensors, etc...Disconnect your fuel line and turn on the key, although exercise caution because if your pump is okay, there will be a lot of fuel coming from that hose so be prepared..



There should be a schrader valve on the line. Unscrew the cap, and press the valve. This is where you would also hook up a guage to check the pressure.

[sctrini]

Thanks...I am going to have a really busy weekend with family and all that so I'll have to this next week. Just two questions...do I need a special type of guage to hook into the schrader valve? Will this be under the rear seat?

Thanks...

[Bloodrunsdry]

have you checked the relay? i know there is a way to jump the pins to find out if the pump is working maybe its just a bad relay.

[kevinqjhps]

Thanks...I am going to have a really busy weekend with family and all that so I'll have to this next week. Just two questions...do I need a special type of guage to hook into the schrader valve? Will this be under the rear seat?

Thanks...


Just remove the cap on the valve, and press it. If gas comes out the pump is putting out some pressure. A fuel pressure guage looks like a compression tester. It would not be part of the cars tool kit.

[sctrini]

have you checked the relay? i know there is a way to jump the pins to find out if the pump is working maybe its just a bad relay.

The Bently manual has a pretty good description on how to test the relays and the fuel pump...step by step, pages 190 - 194 in the electronic version.

[kevinqjhps]

p.s. did you try a shot of Starting Fluid?

[sctrini]

What is Starting Fluid and how and where would I shoot it? Is this something I shoot directly in the cylinder? Years ago I shot som gas directly into the cylinders of a motorcycle for a similar situation...but please forgive my ignorance as I have never heard of starting fluid...

[kevinqjhps]

What is Starting Fluid and how and where would I shoot it? Is this something I shoot directly in the cylinder? Years ago I shot som gas directly into the cylinders of a motorcycle for a similar situation...but please forgive my ignorance as I have never heard of starting fluid...



Any auto parts store carries starting fluid. It is in a spray can. Take the air filter out and spray a 3-4 second spray into the housing, as soon, I mean like NOW, as you spray it have someone turn the key, and try to start the car. If it starts you know you have a fuel related problem.

[sctrini]

Holly crap...that would be simple...thanks a bunch. I'll try that this weekend.

[sctrini]

One more question on this...my car has an aftermarket airfilter...do I need to take my air filter off to do this or can I spray the starting fluid directly on the air filter...I know this is a silly question but I just want to be sure before I do it...

[downeaster1]

Guaranteed your crank sensor. I went through the exact same thing, replacing nearly my entire fuel system. I'm almost 100% sure.

[Seeker]

Any auto parts store carries starting fluid. It is in a spray can. Take the air filter out and spray a 3-4 second spray into the housing, as soon, I mean like NOW, as you spray it have someone turn the key, and try to start the car. If it starts you know you have a fuel related problem.


:nono


That is not a good place to shoot in the starting fluid. If you shoot it in there, it will hit the MAF and might mess it up.

take the snorkel right off the throttlebody and spray it into the TB directly.. that way you bypass it going thru the MAF.

[Seeker]

Guaranteed your crank sensor. I went through the exact same thing, replacing nearly my entire fuel system. I'm almost 100% sure.

he said he was getting spark...

wasnt your spark dead when your CPS went out?

[downeaster1]

he said he was getting spark...

wasnt your spark dead when your CPS went out?
Nope because we tossed some starter fluid into the throttle body and it cranked right up...sorta...it was more like the engine was having a seizure.
Damn, Do I love my E36 <3

[Seeker]

Nope because we tossed some starter fluid into the throttle body and it cranked right up...sorta...it was more like the engine was having a seizure.
Damn, Do I love my E36 <3

this is the part that confuses me about the CPS


Bentley dont seem to explain very well what all DOESNT work when the CPS goes out...

I would think since the ECU has no reference to the crank position that it couldnt time the spark correctly and just not fire until the CPS was fixed.

Obviously, though, if the CPS goes out, the Fuel Pump wont come on.. as in your case.

[sctrini]

I have a tonn of family over for the weekend so I am going to try to check some stuff tomorrow...I am going to pull the back seat out and listen more carefully for the fuel pump humming...I am also going to verify that the fuel pump is getting power using a voltmeter and following the procedure in the bently manual. when it gets dark I am going to verify that I am getting spark. I am sure I was tho...

[Seeker]

just remember that the pump wont come on with the key to ON position alone.. the engine MUST be turning over either with the starter or while its running to keep the pump going.

if the CPS is bad, the ECU wont get a signal to activate the FP relay to turn the FP on.

So if you are going to try and "listen" to the pump.. you gotta do it while the engine is turning over.. it would take two people to do it, unless you rigged up a remote starter.. which would be a bitch to do under that intake manifold...

[sctrini]

just remember that the pump wont come on with the key to ON position alone.. the engine MUST be turning over either with the starter or while its running to keep the pump going.

if the CPS is bad, the ECU wont get a signal to activate the FP relay to turn the FP on.

So if you are going to try and "listen" to the pump.. you gotta do it while the engine is turning over.. it would take two people to do it, unless you rigged up a remote starter.. which would be a bitch to do under that intake manifold...

The Bently manual says how to bypass the relay to make the pump run without starting the engine...it says to jump the sockets for terminals 30 and 87 of the fuel pump relay and the pump will get power without the engine running. This way if the pump runs I know it may be the FP relay or the CPS as above. If it gets voltage and does not run I know it is the pump. Bently said it may also be the DME relay right next to the FP relay.

[Seeker]

ahh.. well if you jump the FP relay.. yea.. it'll come on w/out turning the engine over...

you would be surprised how many people think that putting the key to "on" alone will make the FP come on.. lol


Yea, the Bentley has about 5 different areas to trouble shoot a fuel delivery problem.. just gotta rule them out until you find the trouble area.

[sctrini]

ahh.. well if you jump the FP relay.. yea.. it'll come on w/out turning the engine over...

you would be surprised how many people think that putting the key to "on" alone will make the FP come on.. lol


Yea, the Bentley has about 5 different areas to trouble shoot a fuel delivery problem.. just gotta rule them out until you find the trouble area.


Man...I am hoping it is the FP relay...that is the easiest and cheapest thing to change in this entire scenario...

[sctrini]

OK this is what I have done on this...I jumpped the fuel pump relay between terminals 30 and 87 as describbed in the Bently manual and checked for voltage across the fuel pump connector terminals. Nothing...the fuse is good. Can a bad DME or crank pos sensor cause this? How can I check the DME relay.

However, my battery is kindda dead. So I took it to the Auto Zone to be charged.

Can I connect the fuel pump directly to the battery just to see if it runs? Would that damage the pump if it's good?

I will double check this again tomorrow. Any input is greatly appreciated.

[sctrini]

With a full charged battery I tested everything I can test and I have concluded that the problem is the fuel pump. Thanks for your help.