I can’t get this thing to idle properly. I know, that’s every topic in here.. smh

[Amcubayt]

So I’ve check every standard thing that would make the car idle incorrectly

- smoke tested, minor leak in one hose, replaced and not leaking anymore. Still idles bad (shakes)
- new spark plugs
- new ignition wires
- new distributor cap and rotor
- icv cleaned and replaced
- new fuel pulp and filter
- afm tested
- head gasket replaced
- valve cover and rocker seals replaced
- ecu swapped
- compression test 150 on all cylinders except one that was around 130.
- tps tested with known working and car knows when it’s in idle
- I have not changed the cps.. didn’t see the need.
- 02 sensor changed with new sensor. No marbles.

im lost :/

one thing to note however, fuse number 20 keeps blowing and the ac never worked on this car nor has the blower.. probably not related, I just wanted to point that out. All other fuses are fine. I’ve removed all wiring going to ac and blower and fuse has stopped blowing but car had a problem starting and still idles incorrectly.

help?

[uturn]

Since you're throwing money at it.... maybe a new cam shaft and rockers. Check to see if those don't have unusual wear.

[Amcubayt]

Is there a way to test it? I have done a valve adjustment and everything seems to be within spec of the Bentley Manuel

[cheffy30]

thermostat? clogged injectors? try the Italian tune-up [no offense] red line on the highway for a quarter mile... just sayin. m20s... sent from hell using Tapatalk

[roguetoaster]

You didn't mention timing verification. So check that, test the CPS, check injector function if it comes to it.

Also look at the actual plugs for the ICV, TPS and CPS.

[Amcubayt]

I will check the plugs for those when I get home and I actually replaced all the belts, including the timing belt when I replaced the head gasket. I triple checked my tdc / o/t marks on cam and crank. It’s on time.

[tomstin]

The best, all in one place, idle documentation I've found is here: http://www.verrill.com/car/e30_idlefaq.shtml

[Amcubayt]

Cheffy30. How could my thermostat be the problem? That is something I didn’t check and I was taking a look at it yesterday. I noticed the bleeder screw seemed to have a stuck bolt in it? No coolant came out when I removed the 8mil on top of the thermostat.

[cheffy30]

Cheffy30. How could my thermostat be the problem? That is something I didn’t check and I was taking a look at it yesterday. I noticed the bleeder screw seemed to have a stuck bolt in it? No coolant came out when I removed the 8mil on top of the thermostat.

the thermostat gets and sends signals through afm. I dunno. it's all part of the idle scene man... sent from hell using Tapatalk

[moatilliatta]

Double check cam timing?

Id replace injectors over cleaning them.

https://www.fiveomotorsport.com/0280155885-bosch-gen-3-bmw-m70-m73/

The thermostat has no communication on the M20

Do you have a better description of how it idles or video?

[Amcubayt]

I will double check the timing but I was very thorough when I installed the timing belt because I had the engine out and didn’t want to screw it up. Also here’s the link to a detailed video of what I’ve done so far and how it idles.

https://youtu.be/dGfZESGyhqI

about the fuel injectors, I forgot to mention I replaced the filters, spacers, caps and 0 rings about 2 weeks ago. No change.

[Gregs///M]

How did you test the afm and what makes you think a 30 year old AFM is still good?

[Amcubayt]

I just replaced it with a known to be working one and there was no difference. Do you have suggestions on how to test? If so I’m so willing to try.

[cheffy30]

afm has a lot to do with idle. temp is part of the afm. if it's original it's 30 years old... suspect that too sent from hell using Tapatalk

[digger]

fuel pressure? all injectors firing?

what does it do when you crack the throttle? does it "clear up" does it drive ok