$700 craigslist steal 1984 318i rough idle issue

[EmTwenty]

Whats up r3v! So yesterday I bought a 1984 318i off craigslist for $700 bucks. I bought it knowing it had a high idle and wants to die when you put it in drive. Otherwise once its past 3k rpm it runs good. After doing some troubleshooting all day we came to the conclusion its a vacuum leak. We sprayed starter fluid on any possible leak with no avail and cleaned the IAC. We noticed that when you pump the brakes multiple times the idle dips down and it wants to die. So we think it maybe has a brake booster vacuum leak, or the check valve has gone bad. Just seeing if anyone has any suggestions on what it might be. Your input is much appreciated!

$700 bucks at it's finest!

[Blackout]

Why EmTen EmTwenty?

[Holland]

I think auto is more of a concern...

[EmTwenty]

Haha I have a 1987 325is too. And for 700 bucks I could care less that it's automatic. It shifts so smooooth.

[matt0300]

My car idle dips too when I push in the breaks. Someone should chime in on that....

[e30jake]

Tried the penny trick yet?

[Pantless Spency]

AFM or ICV.

[iamsam]

needs less M10 and more M42.

[EmTwenty]

So we did some more troubleshooting today. we noticed when you move the steering wheel left and right the idle dips down and wants to die, just like pumping the brakes. So I think just having a load on the engine at low rpms angers my m10, also inducing a misfire. I have a feeling there is a big vacuum leak somewhere. Or maybe it has a vacuum advance issue? I unplugged the vacuum advance solenoid electrical plug and nothing changed with the 2000rpm idle, you guys think maybe that's the culprit?



It's the electrical plug connecting to vacuum advance. Once again thanks for your 2 cents!

[EmTwenty]

Tried the penny trick yet?

I haven't tried the penny trick but I cleaned the ICV and i could hear the valve moving. Also when it was running i unplugged the electrical connector and the idle went up so i don't think the ICV is my problem.

[irish44j]

vac leak would probably cause a high idle, not a low idle/dying.

have you checked the timing?

[shadowbethesda]

Just bought the same car. Pics and mileage and more details?

[shadowbethesda]

Also just out if curiosity... Can you please post a pic on the other side of the engine so we can see that all the vacuum hoses are hooked up and hooked correctly?

[e30jake]

I haven't tried the penny trick but I cleaned the ICV and i could hear the valve moving. Also when it was running i unplugged the electrical connector and the idle went up so i don't think the ICV is my problem.

Same thing happened with mine when I first got it. It didn't run right until I stuck the penny in. Now I have to feather the throttle for a minute or two every once in a while to wait for it to warm up, but once it does it runs smooth. If none of the next few things work for you, I would still say at least see if it works.

[dougie30]

noob question...

could someone please explain what the penny trick is, and what it does