HELP! Poorly running 1991 318is Update

[ilikeallcars]

I have a 1991 318is that is currently running very poorly. At first cold start up it runs fairly nice but the the more it warms up the worse it runs. It starts to miss at idle and misses in certain areas through out the rpm range when trying to drive it. If anyone has any ideas I'd love to hear them. I need to know what to test and how to test it. I consider myself a fairly good mechanic, but I'm new to BMW's. The check engine light isn't on, and I have scanned the computer which didn't turn up any codes.

I need some more help guys. I have tested fuel pressure, tested idle control valve, replaced temp sensor, and fix one vacuum leak. The car still runs very rough at idle and if you floor it. Could it maybe be a bad throttle valve switch, and does anyone know how to test it? Any more ideas?

 

[epj3]

Sounds like a bad temperature sensor (the one for the ECU, not the VDO/gague one)

 

[ilikeallcars]

Which sensor is which. I found two. One had two terminals and the other had one. I replaced the sensor with two termials. It didn't seam to do any good.

 

[epj3]

Which sensor is which. I found two. One had two terminals and the other had one. I replaced the sensor with two termials. It didn't seam to do any good.

I'm not sure, its whatever one says bosch on it

 

[ilikeallcars]

Do you know where I can find a manual that covers the M42. I have a manual for the E30 but it doesn't cover the M42 engine.

 

[E30m42cab]

I use the Haynes manual for the E30 3 series, but I have to use the Haynes manaul for the E36 3 series because it covers the M42 engine. Also, this website might help. (Email Brendan, he should be able to sort it out for you)

http://www.esatclear.ie/~bpurcell/

I'm assuming you've checked your spark plugs for correct gapping, etc... or if they're firing properly.

 

[epj3]

buy a bently, you'll pay as much for shipping the bently manual as a haynes costs.

 

[ilikeallcars]

Thanks for the help guys. I haven't even got a chance to drive this car yet and am looking forward to the day it runs properly. Its my first BMW so thus far I'm not very impressed. I'm sure that will change in the future.

If the engine is mis-firing, is that ussually an ignition problem? And if so, what types of things would cause the ignition system to have trouble? Do the type of spark plugs really make a difference?

 

[epj3]

Thanks for the help guys. I haven't even got a chance to drive this car yet and am looking forward to the day it runs properly. Its my first BMW so thus far I'm not very impressed. I'm sure that will change in the future.

If the engine is mis-firing, is that ussually an ignition problem? And if so, what types of things would cause the ignition system to have trouble? Do the type of spark plugs really make a difference?

Well, your problem is very uncommon. I would be less impressed with your buying skills than the 318is - which is undoubtedly one of the best cars with one of the best engines built with a 3 series designation. So yea - your opinion will be changed.

Ignition system misfiring? Sounds like bad coils to me but you will never know if you don't take the few minutes to go outside and test...

 

[Sntandrew]

Check these things in this order as per your symptom

1991 BMW 318i M42

ENGINE CRANKS BY WILL NOT START


1. Defective DME control unit
2. Defective ignition coil
3. Defective ignition switch
4. Faulty spark plugs or ignition wires
5. Defective Primary ignition wiring


IMPROPER ENGINE IDLING OR STALLING


1. Defective DME control unit
2. Defective primary or secondary wiring
3. Faulty spark plugs
4. Defective ignition coil


POOR ACCELERATION


1. Defective DME control unit
2. Faulty spark plugs
3. Defective secondary ignition wires
4. Defective ignition coil

I hope this at least leads you in the right direction I will keep looking for any additional information meanwhile, reply with any questions you may have and hopefuly together we all can help solve your temporary set-back.

 

[Febi Guibo]

Just as an FYI, although the E30 Bentley manual has omitted the 318iS, you can go to the Bentley publisher's forum and request PDF pages of the relevant E36 manual... they are pretty good about responding.

If someone with an E30 318iS needs pages, please PM me.

 

[Jtuner]

ummm... m42's don't have ignition coils and distributors... they have a coil pack.. This is what my car did when i got it at first,, i changed the AFM and coolant temp sensor,, it runs like a dream now!! Good luck with this,, if you change all of that, try the ECU,, I had an IX with a bad ecu that ran like this..

 

[Febi Guibo]

no distributor, but fyi / strictly speaking we do have ignition coils...

the 'coil pack' you mentioned is basically 4 ignition coils bolted together.

 

[epj3]

ummm... m42's don't have ignition coils and distributors... they have a coil pack.. This is what my car did when i got it at first,, i changed the AFM and coolant temp sensor,, it runs like a dream now!! Good luck with this,, if you change all of that, try the ECU,, I had an IX with a bad ecu that ran like this..

You're the first one to mention a distributor... but yea.