Jump to content
WI BIMMERS - Wisconsin's BMW Community
  • 0

E30 running problems

keeperofchaos

Asked by keeperofchaos,

 Share

Question

keeperofchaos Newbie

keeperofchaos

Posted
Posted

I recently purchased an e30 325is. I got the car knowing it needed a little work probably just a tune up. I did the tune up (plugs, coil, fuel filter, cleaned ICV, cleaned AFM pulled injectors and cleaned and tested them, and i even took and cleaned all the contacts on the distributer cap and rotor) and it still runs like dog shit. it usually won't stay idling and if you finally do get the RPMS to come up it will backfire like crazy shooting flames threw the exhaust. I tested the AFM and it seams to be working properly. Does anyone have any idea what to try next. I am about to give up on this thing... BTW i need this running before the snow comes, i need to get the E36 put away.

<3

Link to comment
Share on other sites

23 answers to this question

Recommended Posts

  • 0
B C Apprentice

B C

Posted
Posted

Is the issue when the car is cold, @ operating temp, or both?

Did the car suddenly start running badly or did it gradually get worse?

If you had access to the AFM resistance data, I imagine you would be able to find the coolant temp sensor test values. Test the coolant temp sensor.

Check the C191 connector under the intake manifold for corrosion. http://www.verrill.com/car/idle/e30_idle_c191.shtml

The bad idle may not be related to the backfiring. Does the idle control valve buzz with the engine off and the ignition switched on?

You should also test the throttle position switch on the bottom-side of the throttle body. There are 3 pins. One for ground, another for idle, and the other is for full throttle. With the car off and the throttle closed, there should be continuity between the ground and idle pin. Open and close the throttle by hand multiple times to confirm that you have continuity (I have had a throttle switch that worked 5 out of 6 times, so it gave me a continuity reading but occasionally I would have a hard start or idle issue). There should also be continuity between ground and the full throttle switch with the throttle fully open.

Posted Image

If the ECU does not receive a signal from the switch at idle, it will try to keep the car running on the partial throttle fuel+timing maps, If for some reason the full throttle switch is stuck on (ive never heard of it, but its possible) then the car will try to run full throttle fuel and timing maps at part throttle.

You should verify that the cam timing hasn't jumped a tooth.

Verify that the ECU grounds on the shock tower are clean and in good shape.

Give the ECU a reset by disconnecting the battery and re-connecting it (Motronic 1.3 short term fuel trims are learned within 2-3 minutes of driving after reset in my experiences)

and try a spare ECU if there is one available.

Link to comment
Share on other sites
  • 0
keeperofchaos Newbie

keeperofchaos

Posted
  • Author
Posted (edited)

Not the AFM. I do hear the ICV buzzing when the key is on. This is driving me crazy. WHY is it running so rich. :( i just need to get this thing running. It runs like poo when cold, it usually wont even stay idling, when you hit the gas peddle it will die 97% of the time and if it doesn't die it just backfire. If you can get it to warm up it runs worse and backfires at idle again that is only if you can keep it idling.

Edited by keeperofchaos
Link to comment
Share on other sites
  • 0
B C Apprentice

B C

Posted
Posted

Not the AFM. I do hear the ICV buzzing when the key is on. This is driving me crazy. WHY is it running so rich. :( i just need to get this thing running. It runs like poo when cold, it usually wont even stay idling, when you hit the gas peddle it will die 97% of the time and if it doesn't die it just backfire. If you can get it to warm up it runs worse and backfires at idle again that is only if you can keep it idling.

I've bumped into bad fuel pressure regulators on a few E30s. The diaphragm inside leaks and pulls fuel through the vac. line into the intake manifold. pull the vac. line going to the FPR and see if it has fuel in it. If so, replace the FPR.

Link to comment
Share on other sites
  • 0
jockhater2 Newbie

jockhater2

Posted
Posted

I recently purchased an e30 325is. I got the car knowing it needed a little work probably just a tune up. I did the tune up (plugs, coil, fuel filter, cleaned ICV, cleaned AFM pulled injectors and cleaned and tested them, and i even took and cleaned all the contacts on the distributer cap and rotor) and it still runs like dog shit. it usually won't stay idling and if you finally do get the RPMS to come up it will backfire like crazy shooting flames threw the exhaust. I tested the AFM and it seams to be working properly. Does anyone have any idea what to try next. I am about to give up on this thing... BTW i need this running before the snow comes, i need to get the E36 put away.

<3

If your getting backfiring?

that sounds like the pistons are firing at the wrong time. Is the backfiring coming out of the tail pipe or up in the engine bay?

Do you have a Bentley manual? Biggest help is that book.

Link to comment
Share on other sites
  • 0
B C Apprentice

B C

Posted
Posted

The Bentley is good but it is definitely not any sort of bible. The index really irks me sometimes. I remember one time looking for something ignition related and it ended up being under "Transistorized coil ignition (TCI-i) system" in the index. double-you-tee-eff mate.

Link to comment
Share on other sites
  • 0
jockhater2 Newbie

jockhater2

Posted
Posted

The Bentley is good but it is definitely not any sort of bible. The index really irks me sometimes. I remember one time looking for something ignition related and it ended up being under "Transistorized coil ignition (TCI-i) system" in the index. double-you-tee-eff mate.

That is true. The index sucks dick.

but otherwise it is basically a bible.

I owe that book like $5,000 grand in savings for my jetta.

I've only had to use it a couple of times for my e21.

Link to comment
Share on other sites
  • 0
keeperofchaos Newbie

keeperofchaos

Posted
  • Author
Posted

yeah.....still no fixins due to not giving fucks. have not touched the car for 2 weeks and I'm going out west for 2 weeks this coming week. so im taking it to a shop and telling them have fun. lol. but before i take it ill try and get vid of how it was running and post that along with what they find, just to help with anyone in the future. thanks everyone for the input its just to cold to work on it and i don't really have the resources i used to working in a shop. Wish me luck :)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Answer this question...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Go to question listing
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.

  I accept