could really use some help...88 325 ic

[Frajo]

Itʻs been about 3 weeks since I replaced the ICU computer. it has been working fine until last night. Same symptom... NO GAS going to the engine... after about ten tries starting and giggling some wires at starts again. Any Ideas???

[Jared at Pelican Parts]

Did you check the actual fuel pressure at the injector rail? What is it reading?

[Frajo]

not with an actual pressure gauge because I donʻt own one. when I disconnect the fuel line just before the pressure regulator It is either nothing... or I can fill a 16oz cup in 5 secs. Do you think the pressure being off would cause intermittent stopping of the fuel supply reaching the engine all together? I will borrow a tool and get a reading though...

On other note... I opened the lid to the fuel pump, just to check the wire connections and noticed there was a small amount of fuel seeping out from around the top of the pump as if there was a lot of pressure. There is a full tank and I am positive that the O ring gasket is good in there

[Jared at Pelican Parts]

You need to clarify here. You're saying that sometimes, you'll get fuel out the line at the engine and then sometimes not? If the fuel pressure isn't at spec, the engine wont run. The fuel pressure regulator determines the overall pressure. 16oz. in 5 seconds is well within delivery spec. Operating pressure should be between 40-45psi depending on engine load.

This sounds more like a fuel delivery problem. Check your fuel filter first for blockage, then verify that the pump is running continuously when the engine is running. You need to locate the fuel pump relay and check for 12V between terminals 30 and 87. The fuel pump relay is the middle one on the small three relay board to the side of the air filter housing.

If you jumper the relay and the fuel pump does not operate, you have a bad fuel pump.

Why did you replace the ECU?

[JhwShark]

The leaking out of the FP...is a concern. Does this FP have an internal check valve?? may be bad or the seal ring is not good...

[Jared at Pelican Parts]

Originally Posted by JhwShark

The leaking out of the FP...is a concern. Does this FP have an internal check valve?? may be bad or the seal ring is not good...

A leaking fuel pump is a bad fuel pump. replace it.

[coolbear1]

The fuel pump is suppossed to come on momentarily when you turn the ignition switch on, to pressurize the system.
If the ecm does not get a signal from the crank sensor that indicates the engine is turning, the pump will not stay on.
You can however over ride the ecm by jumping ot the fuel pump relay.
This is done by removing the relay and putting a jumper in the fuel pump relay receptical.


Try this link:

http://forums.pelicanparts.com/101-projects-discussion-forum-bmw-3-series-e30-e36-1982-2000/378508-fuel-pump-trouble.html

[Frajo]

I really appreciate the feed back... Hope this info helps...

Car was not starting./ then would start and periodically stall out... fuel supply seemed to intermittently cut off.
Tested/ swapped fuel pump.
Tested/ swapped fuel pump re;ay.
Tested/ swapped temp sensor.
Tested/ swapped temp switch.
Tested/ swapped top position sensor.
Removed the intake/ inspected all vacuum and fuel hoses. Vapor canister hose is bad. Replaced with a used hose. All else Good.
Inspected spark plugs, wires, rotor cap and coil. All Good.
Tested/ swapped fuel Pressure regulator. Good (volume test as described in the bentely manual did not pressure test yet.)
20 min test drive. started acting up again. .
Tested/ swapped instrument cluster. RPM and Temp, gauge not working. (could it be an SI board thing?)
Swapped Computer (Ignition Control Unit) with a used unit. Seems to have solved the problem with the fuel related issue.
1hr. test drive. All Good...
All of these Tested/Swapped are known to be working parts swapped from a running car. None of these corrected the problem except the ICU which worked fine for about three weeks.and then same exact symptom... and for clarification, the fuel stops delivering before the pressure regulator as I found when doing the volume test... also while doing the volume test I jumped the wires for the pump relay which didʻnt work at the first several cranks and then it did... and it is possible I did not inspect the fuel pump ORing well enough but I remember it looking good.

[coolbear1]

Did you jump out the relay and do the fuel pump test? you mentioned you jumped out the relay and it did not work. If you did what Jared said and jumped out terminals 30 and 87, you can hear the pump running with the engine off. If you did not hear the pump, you have a bad pump. Unplug the pump under the back seat nnd jump out the fuel pump relay. put a meter on the plug and see if you have 12 volts at the fuel pump plug.

[Frajo]

Thanks. Iʻll give it a try with the meter and the pump disconnected... I did try jumping it with another working fuel pump though with the same results. Is it true that when the fuel system is pressurized with the key turned to the on position the pump will stop?

[coolbear1]

That is correct. The ECM will not let the pump run to an engine that is not turning.
The reason is, if you had a massive fuel leak, and the engine stopped, the pump would continue to pump fuel as long as the key was on. If it did it could be very bad in the event of an accident.

Bar B Q Frajo, or coolbear, or mama bear and baby bear.

If the ECM does not get a signal from the crank sensor that the engine is turning it will not continue pumping fuel.

[Frajo]

Finally started new testing. I have 11.57v coming from the fuel pump relay. I jumped 30 and 87 on the relay and got a reading of 11.57v at the fuel pump. Would we agree that the pump is bad? Is the slightly lower than 12volt reading something to be concerned about?

[coolbear1]

You have voltage at the fuel pump plug after jumping the relay? Does the pump not run after you re-connect the plug at the pump?
Your car an E30 or E36. Is the pump in the tank? Under the back seat? ether way if you jump the relay properly, and don't hear the pump running, and you are certain you have 12 volts (give or take one volt) to the pump, pull the pump out.

After you have it out you can bench test it.

Please don't hurt yourself. If you don't fell comfortable with removing the pump, then don't!
You connected another pump before, I assume to the plug only? Did you do the same with the relay jumped?

Remember, if you have the in tank pump, with three leads on the plug, it has the fuel level sensor itergral to the unit, you may be getting voltage from the sensor.
Ok, I went back through the thread and I see you have an 88 e30 with the in tank pump.
If you jumped the relay as Jared discribed at 30 and 87 in the fuel pump relay socket, and you don't hear the pump, it is bad.
This by-passes everything.

[bostogrun]

Many times electrical parts such as fuel pumps, blower motors and starters for that matter work intermitently until they ultimately fail. It has to do with small cracks in the windings. When cold the wires have continuity however when they heat up they exapand casuing open an open circuit thus rendering the component useless.

[bostogrun]

Nobody has said how many miles are on this fuel pump. Anything over 150K is borrowed time.

Maybe you could check the resistence of the pump circuit when its then working then checking the same circuit when it wont run. if the resistence is significantly higher in the no start situation it woud prove my theory that the pump has an internal wiring issue

[Frajo]

Thatʻs a good point bostogrun. The pump was "supposedly" replaced 5 or 6 years ago by some local yokal repair shop but when I looked at it ,it seems to be an older one judging by the older style micro screen an discoloration on the pump. In response to coolbear... I have never heard the pump run when I jumped the wires. I just canʻt see how if it works at all it will not run when I jump the wires. It seems like it should run and cut out intermittently like it does when it is all hooked up. maybe there is something about that I just donʻt understand fully... just for S&G I replaced the pump with a working/failing used one...again... to see how it works.It works but is whiny sometimes. I think I will try jumping the relay with this one and listen. surely I will be able to hear that one running. I am ready to buy a new pump but just want to make sure I am chasing the right problem.

[Frajo]

Update... I jumped 30 & 87 with the other FP installed in the tank and still no sound. I still get 11.6v out of the FP wires with the ignition on and relay jumped. (the 2 outside wires on the 3 wire harness) confused as to which wires are for the FP and which is for the level sensor. If I get no action from the pump with the wires jumped, and that means the pump is bad then why does the engine run when the relay is in. am I missing something with this test?

[bostogrun]

It could be the wiring in the jack is corroded. Maybe you are not making a good connection with your jumper. Try poking and probing it in different spots if you cant get it too run its definitely a fuel pump issue. Like I said sometimes electrical probelms can be intermittent and capricious esspecially if a component with internal windings like a motor or ignition coil are involved.

When does the car not start? When it's cold in the morning or does it not restart after its been run awhile like at the gas station? If its the latter it would really be most likely what I was saying.

[Frajo]

It seems like it can happen at anytime. sometimes will die while driving. sometimes on a coldish start. one thing that it does almost every time on a cold start is... it takes a longer than usual cranking to get the engine to turn over. dont know if it is related or not

[coolbear1]

hard to read but see if this helps


The fuel pump terminals should be the brown (ground) and green/violet wires(12 volt)

hope this helps.