Car wont start!! Help! 1987 325is

[e30loverSC]

Yesterday I was driving for about an hour around town with no issues. I park and run in to the dry cleaner to drop my clothes and come back in 3 mins maybe.. and it wouldnt start. I turned it over a few times and the first couple of times it would sputter a but then eventually nothing . Prior to this i have had a few events where the car would suddenly die while driving but after turning the key off for a second it would start back up. Sometimes it would die and I would have to let is sit for about a min. then it would start quickly easily like normal. Never had any issues with the car. I'm thinking fuel pump but Idk which one and why both would quit working. I also swapped the main and fuel relay and still nothing. Also yesterday when the car wouldn't start i noticed the auxiliary fan wasn't coming on. It normally comes on with the key at all times.

Help!! - Hunter Allen

[urbancynic]

First off, do you hear anything out of the fuel pumps at all?

If not, it is possible that if one died the other went shortly after due to stress from the heavier load placed on it.

However, you really need to determine what the cause is. Are you getting spark, how about fuel?

Check out your coolant temp sensor for the ecu. That can play havoc on the vehicle running... or not running.

Grab your Bentley manual (you do have a Bentley manual, dont you?) and start doing some tests.

[Adrian_Visser]

Coolant temp sensor won't cause a no start. Pull a plug and check for spark while cranking. No spark it could be CPS or main relay, if you have spark dead main fuel pump or fuel pump relay.

[MTechnikII]

My experience with such a symptom of car dies and then in a minut it starts, tells me it might be a relay, either feul pump relay or main relay . the relay gets hot then doesnt' hold the contact, sometimes they might click and you can hear it but since they get old the contact surface gets pitted and doesn't let the current flow as it used to
check the relays under the hood , main relay, fuel pump relay .
I hope this helped
Don't forget to check the relay base too see if they are in good condition, use some contact cleaner if needed
Henry

[e30loverSC]

I tried swapping both relays already. And I also took the hose off the pump underneath the seat and tried cranking and got no fuel coming out... or noise. The one underneath the car doesnt seem to make noise either.

[jlevie]

The first step in diagnosing and fixing this is to check for spark when cranking the engine. No spark could be:

No timing data to the DME
DME power, ground, or START signal problem
Bad coil or no power to the coil

If you don't have spark at the plugs but do at the coil wire the distributor cap rotor or ignition wires could be bad, or the timing belt could have failed.

If spar is present when cranking the engine the next step is to measure rail fuel pressure while cranking. If the pressure is low or absent the cause could be:

Empty tank
Bad fuel pump relay or fuse
Clogged filter
Obstructed line
Bad fuel pump(s)
Bad FPR

If there is spark and normal rail pressure the next most likely candidate is one or more intake leaks.