87 535i will not start

[camper1159]

87 535i

Will not start. If I floor the pedal it will chug, but not run.

It wouldn't start twice today as I was out doing errands. I opened the hood and reseated the coil wire for grins. Both times it started and then ran great. Once home it would not start. Just the occasional chugging when floored. (I know, it's injected, I was desperate).

No sound from fuel pump with ignition switch to on.

No power at fuel pump fuse until cranking.

My guess would be the fuel pump relay, since the car ran great after banging around under the hood earlier in the day.

A fuel pump goes, and that's it (doesn't it?).

Can any of you experienced 535i bimmerfahrenmeisters tell me just which relay is the fuel pump relay? My guess is the one right outside the fuse box by the fuel pump fuse?

It's damn cold and dark out there at the end of my driveway.

Any clues from all you experienced bimmerfahrenmeisters?

[fastshivy]

you need to check the fuel pressure with a gauge...sounds normal from what you are describing so far. Could be a MAF sensor or 100 other possibilitys. A good book will help alot.

[miniman_7]

Sounds like the fuel pump to me.

Try turning the key to position 2, leave it for 2-3 minutes, then try starting.

When my pump went, sometime it would run, sometime not. Then it just wouldn't. Leaving it at position 2 for a few minutes would let the pump build up enough pressure to start, but would soon die.

If you change the pump, I'd do the filter too especially if it hasn't been done for a while.

[camper1159]

Thanks for the responses, guys.

Still trying. I let it sit all night nose down the hill in the driveway. It actually started this morning and ran long enough (although poorly) for me to get it 3/4 of the way up the hill towards the flat area where I will be changing the fuel pump.

Your advice about leaving the switch on for a few minutes sounds good, maybe the low pressure transfer pump will build up enough pressure for me to get it the last 20 feet up the hill and onto some ramps.

After doing a search of this site, I jumped contact 87 and 30 of the relay, but had no luck getting it even to chug. I guess it's the fuel pump.

Thanks for all the input.

Any other ideas before I shell out $211 for a new fuel pump?

Danke schoen!

[fastshivy]

Could be the fuel pump. I would still check it with a fuel pressure gauge or, at least crack a line to see what is going on. You don't want fuel spraying everywhere so be careful. Jumping a relay is a good idea to pressure check one and bypass that part of the system.

You can also pull the plug from the MAF sensor and see if it runs better.On some of the older systems if the MAF is bad the computer will revert to a default fuel curve and run better. This is only diagnostic if it runs better....worth a shot. keep us in the loop so we can all learn.

[camper1159]

Replaced the fuel pump.

Now it starts, but runs poorly. It acts like it needs a tune-up. It used to run just fine.

Sometimes stumbles, and idles about 1800 RPM.

Where would I find the MAF sensor? What can you tell me about the MAF sensor? It does seem odd that two things go at once...

[fastshivy]

Between the air filter and throttle body...closest to the air filter box...it has a plug in wire and is round. It actually sits in line in the intake hose so it can measure the amount of air going in the engine...based on this it tells the injectors how much fuel to squirt.

Is your spark nice and blue?

What does the fuel pressure read?

[da_bull]

A clogged fuel filter would make it run poorly. Might be worth a quick check. It may be over 20 years old...

[camper1159]

I replaced the fuel filterjust two months ago. I just yesterday did the fuel pump. Do you think the filter is clogged?

I can't imagine...

Maybe an engine computer or something like that.

It's really cold out there, so I'll have to wait until tomorrow to start poking around.

I'll check the spark then too.

Thanks guys

[da_bull]

It shouldnt be clogged unless the new fuel pump picked up something from the bottom of the tank. I'm sure a good tune-up wouldnt hurt. I remember reading somewhere a long time ago that any internal combustion engine requires

1. Fuel
2. Spark
3. In time

It may not run well, but you have to have those 3 components to make it run. Good luck with your project...

[fastshivy]

Probably time to pull the plugs and run a compression check if it hasn't been tuned in a while. A stuck intake valve will cause those symptoms too. It is probably OK but you have to start eliminating things that don't cost a bunch of parts money.

Dabull is absolutely right...fire, fuel, all in the right sequence.

I doubt you have 2 things wrong...i suspect you never corrected the orginal problem. Very hard to diagnose without the right tools etc. May be cheaper in the long run to have a good tech look at it and diagnose it.

Good Luck

[camper1159]

fuel press good, spark is good, new fuel pump and spark plugs,too.

Will start, but runs like ca-ca.

Air mass meter?

DME?

Anything else?

I have a new AMM on order...

What do you guys think?

[fastshivy]

My bet is still on the air mass meter, but you almost have to plug another one in to find out

[camper1159]

Thanks, bud.

I'll let you know.

I appreciate your thoughts. It's always better with two heads instead of one. My old gang from high school is scattered, but you guys are just as good!

[MEDSTUDENT87]

My 1990 525 had similar symptoms and I changed the fuel filter and it went away, well not really. My car would only represent those symptoms when it was cold out below 32 degrees F. The last time it happened I unpluged the MAF and it started and ran fine. So I bought CRC Electrical cleaner and sprayed it in the box on the MAF and that cleaned it and ever since it runs soooo much better especialy at idle. Just start and and unplug th MAF it should idle good but it woun't drive well at all you can only use 1/4 throttle after that it will stumble. Good luck