Bmw 525i 1990. Runs good for 8 miles, then stops, wait then runs good??

My 1990 E34. 2 months back the same thing happened. I got info maybe the crank pos. sensor. I did replace it and the car has been running with no problems.

Last Wednesday it did it to me again. Starting out at the house driving it about 5 to 8 miles, then putt putt putt then dies. It will not start back. Come back to the car hours later. Starts up good, then drives back home as good as the car drove out.

I am going to check now if the new sensor is damaged in some way. thanks for any help.

You need to figure out what caused it to die.

The fuel pump can start to fail and be intermittant as you describe but it will completely fail soon. You need to see if you have fuel pressure when the car is dead. Can you hear the pump running? Is the filter recently replaced? There is also a relay in the system that can fail.

I am assuming your car is an M20 525i. That would mean it has a seperate distributor and coil. Coils can also fail as you describe. They get hot and stop working.

You are also smart to re-check the resistance and condition of the crank sensor.

The last two options would mean no spark, so check for spark the next time it dies.

If we know whether you are losing spark or fuel when the car dies (or both) we can more accurately help you solve the problem.

Thanks. Yea, I did replace the fuel filter on the m20 motor, first time that it happened. I will do some checks. Maybe the easiest thing to do would be to replace the coil? Get a spark tester?

I am not a fan of replacing parts until you know which one is broken. You would be mad at me if you bought a coil for $60 and all you needed was a $20 relay

Search for the Bently manual for this model BMW, it will have advice on testing individual components.

I personally would pull a plug wire, crank the ngine and ground the plug to something like and engine bolt or bracket to see if it sparks. The spark should jump a 1/4 inch or so gap, you should be able to hear and see it.

I would also take a fuel line loose to see if fuel pumped out with the key on.

These are "backyard" techniques that can hurt you and the car if done incorrectly, like checking spark where you just dumped raw fuel during your fuel pressure test. That could end badly, hence the suggestion to use the manuals techniques

Originally Posted by carmelo22

Thanks. Yea, I did replace the fuel filter on the m20 motor, first time that it happened. I will do some checks. Maybe the easiest thing to do would be to replace the coil? Get a spark tester?

I would recommend that you diagnose the problem before buying parts. I agree with sled that the FP may be on the way out.

You can check for spark with a regular ol' timing light if you have one. Just hook it up as usual and put the inductive clip on a plug wire, have someone crank the engine over and pull the trigger of the timing light. If it pulses, then you are getting voltage to the plugs.

If you don't already have it, I would recommend purchasing or downloading the Bentley manual. There are several posts her with links to a webiste where you can download it. It has a wonderful trouble shooting guide.

The key will be to check things while the car is not running.

Edit: Sled got in his post while I was writing mine.

To Mr Snowsled7 i would never get "mad"?? at you for trying to help me? Thanks for the specifics on the trouble shooting techniques. It does help. I will take everything that I can get.

I would check the distrubutor rotor and plugs

Sent from Joe's Galaxy SIII via BimmerApp

Check the FP relay as well. Examin the socket for corrosion. You may find a really cheap fix.

I can not seem to locate the Fuel pump relay. I do have both fuse panels open and a relay diagram saying nothing about a relay. Thanks.

REmove the 4 screws for the e-box cover on the passenger side of the engine compartment.

ok, There are 3 relays behind the cover??

on an M20 engined car, it should be next to the RHS strut tower in a little box that also contains two other relays, one is the main relay, i forget what the other one is off the top of my head.

Clean and check them all.

Thanks, yes just did, ? Could it be as simple, as a bad battery? Battery is dead after three days of not driving. After I cleaned the relays it would not start.

Thanks, yes just did, ? Could it be as simple, as a bad battery? Battery is dead after three days of not driving. After I cleaned the relays it would not start.

Originally Posted by carmelo22

Thanks, yes just did, ? Could it be as simple, as a bad battery? Battery is dead after three days of not driving. After I cleaned the relays it would not start.

It's possible. These cars require sufficient voltage for the systems to work properly. If your battery is bad, then you need a new one anyway. Let us know if a new one fixes it.

Had the batt tested and it did have a bad cell in it. Will road test tomorrow.

Originally Posted by carmelo22

Had the batt tested and it did have a bad cell in it. Will road test tomorrow.

With a new battery, yes?

A new battery, yes. Waiting to post to make sure it fixed it. Road tested good for two days had a long road test, then stopped again. The same place at the same gas station almost to the foot. The difference this time being. It started back up, put the car in drive then it would die. Maybe 10 times or so. Then just started up like nothing happened. Drove the car back home as if nothing had happened. What to check/do next? thanks

A long shot maybe, but do you think you may have water in the gas?

Maybe anything is possible. I am running the car up and down the road now. Trying to get it to die again.

Originally Posted by carmelo22

Maybe anything is possible. I am running the car up and down the road now. Trying to get it to die again.

I only laugh because, how many times are we here trying to get our cars to die?

I hope it doesn't die again. I know you may then not know what the cause of the problem was, but hey, it will be running again right?

Good luck.

Originally Posted by BMR_LVR

I only laugh because, how many times are we here trying to get our cars to die? .

Really? Laughing here too, as well. It is my wife's car, so it makes it worse, lol. It has only stopped on her. I will try again tomorrow. thanks for help.

O, And it did die in a rain storm.