E30 won't start - grrrrrrrr! - United Bimmer Community

**geodanker** · 11-06-2007, 12:23 PM

Here's the situation...

I've got a '90 E30 which previously was starting and running just fine - until I parked it for a couple months due to a title problem (also grrrr).

Car now refuses to start. Cranks enthusiastically - just no sign of starting. Suspect a no-fuel situation - after much cranking no gas smell at all.

Have another (properly operating) E30 and have swapped out the following parts with no success:

- idle control valve
- main relay, fuel pump relay and the third relay in the group that controls I don't know what
- fuses 10,11 and 21 (associated with 'fuel') are good so far as I can tell

Have pounded vigorously on fuel pump while cranking - no luck.

Quickly checked fuel filter and there is flow through it. Didn't investigate this thoroughly though.

Spark from coil is strong. Didn't check spark at plugs.

Anybody got some suggestions? I strongly suspect that the fuel pump's either no good or not getting power.

FYI, my mechanical aptitude is only about C+.

Please help!

- George

witeshark · 11-06-2007, 01:30 PM

How many miles? My fuel pump quit at about 150,000 and it acted just like you described.

**celsdogg** · 11-06-2007, 01:35 PM

i think i would give your ability a B+ coz you did a lot of good things!

i would grab a volt meter and see if you get anything outta the leads the go to the fuel pump. as witeshark said, i would go strongly with the fuel pump being bad.

**Exilion** · 11-06-2007, 01:40 PM

(you know this but I need to think through) the basic parts of the fuel system are the tank, pump, filter, fuel rail, injector and pressure regulator. The filter is probably fine since you have flow, although I'd go ahead and replace it if it's about time anyway. Can you hear the fuel pump running when you tried to start? If you can't hear the pump running I can tell you a couple ways to test it to see if it's getting electricity and if it's clogged. Basically it involves checking the current at the relay and at the pump. Kind of annoying to do so if it's about time to replace the pump I'd go ahead and do it like whiteshark said.

EDIT: man I need to type quicker it just seems like I'm repeating things.

**geodanker** · 11-06-2007, 02:35 PM

Thanks everyone for your advice and also your support which is appreciated.

Car has about 125k on the clock.

I have now also:

- jumped contacts 30 and 87 on the fuel pump relay - no response in any key position or while cranking. Have never been able to make the fuel pump make any kind of noise.

- removed the fuel line from the fuel pressure regulator. No gas in line and doesn't appear like there has been any for some time. Dry and no strong gas smell.

- removed the mass flow air meter and 'rotated' the vane inside a bunch of times to see if that helps.

I suspect a bad fuel pump or some form of a bad signal which would ultimately power the fuel pump. I could test by swapping suspect pump with the fuel pump in my 'good' E30 - but that seems messy and a lot of work. Is it?

Is there an easy way to directly power the fuel pump?

Complication - I don't have any sort of voltmeter or multi-meter. A 12v DC power supply I can kludge together.

Thanks again very much Comrades.

- George

**HyeTide** · 11-06-2007, 02:37 PM

First pull a spark plugs out and see if they look dry which means no fuel. Try spraying carb. cleaner in throttle body through a vacuum connection. If that starts it than you know its a gas problem. Gas can go bad in a couple of months, have you used fuel stabilizer?

**geodanker** · 11-07-2007, 10:51 AM

Here's the latest everyone...

I hooked up an auxillary power source - 12v dc - directly to the suspect fuel pump. Actually I didn't 'hook it up'... I just touched powered electrodes to the proper electrical contacts on the fuel pump.

What happened was that the suspect fuel pump 'hummed' but did NOT make the pumping sound I expected. The hum was akin to any electrical 'motor' that wanted to 'turn' but was frozen up.

Next, I tried the same experiment on one of my properly operating E30s. This time the known-good fuel pump made proper fuel pump noises - significantly different then the suspect fuel pump.

From this experiment I have to believe that the suspect fuel pump 'motor' is 'frozen'. Indeed, early in my investigations, I had found fuse #10 blown. That's one of the fuel system related fuses, I believe. That data point lines up for me - frozen motor tries hard to turn and blows a fuse when it cannot. That seem right to you guys?

I'm gonna repeat my test lamp experiment to see if power is getting to the fuel pump. I did this yesterday with a no-power result but I've improved my primitive test lamp apparatus since then and I'm gonna repeat the experiment.

I'd like to think that I've got only a single problem - that of a frozen fuel pump - but an electrical gremlin cannot yet be ruled out.

Woo Hoo! Some progress. I'm not terribly intimidated about replacing a fuel pump if that proves to be the culprit.

Please make ANY comments. You guys are great.

- George

**geodanker** · 11-07-2007, 11:42 AM

More info...

Rechecked power to the fuel pump using new improved homemade test lamp. (Note to everyone: Be sure to test the test apparatus)

WooHoo! Indeed power DOES flow to the fuel pump when car is cranked.

This, in conjunction with aforementioned fuel-pump-NOT-making-pumping-noises-when-directly-powered observation leads me to believe that I need to repair or replace the fuel pump.

Yes, I've got a good fuel pump in another E30 that I can swap out. But I don't want to dick around with that one if my suspect fuel pump is definately bad. Eventually, I need all the cars to run don't you know.

What comments does anyone have regarding removal/repair/replacement of the fuel pump. Easy? Intuitive? Remove one and replace with another?

Is there some repair kludge to 'free up' the pump?

Thanks all!!!!!!!

- George

**Exilion** · 11-07-2007, 12:21 PM

Ah it's pretty close to when the pump would die anyway I'd go ahead and replace it. If you have the money I'd just buy a new one it'll last you longer and then you'd have 2 cars to play with.

**geodanker** · 11-07-2007, 02:12 PM

Just bought a fuel pump at semi-local boneyard.

Installation next.

Here's hoping.

Stay tuned...

Same Bat-time, same Bat-station.

- geo

**Exilion** · 11-07-2007, 04:03 PM

Alright good luck. Just post if you get stuck.

**geodanker** · 11-07-2007, 07:17 PM

Went out and bought 'new' fuel pump obtained locally from friendly boneyard. $60.

Installed in minutes - car running perfectly moments later.

MISSION ACCOMPLISHED !!!

Woohoo!!!!

Fuel pump shot craps with absolutely no warning. No intermittant anything. Good when last driven. Not good the next.

I'm pleased to have my car running and thank everyone for their assistance and, equally importantly, their support. I'm not much of a wrench and need some encouragement.

Thank you again everyone.

This way to the Egress, Citizens!

- george