Starting problems

[jopa]

New to this forum.

Car has been cutting out while driving on side streets, freeway speeds or idling.

Sometimes it will resume while coasting, with no more interruptions, other times it must be re-started.

Has always started when cold, except after last time it ran, ~7 days ago.

Yesterday changed in-tank fuel pump and sender to no avail. Will change fuel filter today.

Timing belt not broken.

Not being familiar with the results of various parts not working, I have made a novice's list of possible suspect parts.

Could it be any of these that are causing the problem?

-Fuel Pump Relay

-Fuel Injection Relay

-Non-Return Valve

-Throttle Switch

-Electric Fuel Pump (next to fuel filter)

-Fuel Pressure Regulator

Thanks for your input.

[ronskal]

I would start with electrical. Fuel pump relay is a biggie, I would replace it just to have a spare at least.

I had an 82 528e that I was working on (my GF's 16 year old daughters car), just doing a tune up and stuff. When I finished it would not start! Well, after a half day of technical troubleshooting it turned out to be that when I closed the glovebox it would not start, when I opened it, the car would start. Turns out all the CD's junk etc. in the glovebox were jamming against the computer(ECU) harness (the ECU is above the glovebox). So I removed all the junk, ty-wrapped the harness, reseated the ECU connector and it worked! Check your ECU connector.

Check fuse 1 (16 amp) in your fusebox. Remove it, squeeze the contacts together a little and reinstall. Also clean the contacts. This fuse powers the main and transfer fuel pumps. See if the fuse contacts are dirty/arced. Common problem area. Check all fuses while you're there.

Eliminate electrical areas first, on an older BMW the electrical system is your biggest problem area.

[jopa]

That is a very interesting and unusual occurrence with the glovebox.

I will do as you suggest and check the fuses and clean the fuse contacts.

Thanks for taking the time to respond.

[E28boi]

1. I would check for vaccum leaks first. Does the car idle properly?
2. Check your ignition components too. You may have weak spark.

[jopa]

Changed to a new battery and spark plugs yesterday. I've had suggestions that the fuel pump and/or fuel injection relays may be the problem.

Was told that they were the three attached to the side of the fuse box; problem is there are three relays on both sides of the fuse box.

Does anyone have a diagram (not schematic) showing where these are located?

[E28boi]

I'll check my bentley and get back to you.

[ronskal]

According to the picture in the Bentley book the fuel pump relay is the second one (middle relay) on the right side of the relay panel.
When I say RH side I mean as if you were sitting in the drivers seat, not viewing from front of car.
The relay in front of it is the main relay and the relay behind it is the O2 sensor heater relay.
Unfortunately, the book gives a disclaimer that relay locations are subject to change, and may vary between cars depending on options.

[Conman]

Gremlins, thats my answer

[Slvr e39]

Just wanted to say to Conman and jopa.