1987 325i idle problem

[John Smith]

So I traded a fellow an iPad for a vert with unknown miles on it.

I drove it from Provo to Salt Lake (45ish miles) without any problems... at the stoplights, 75-80 on the freeway, stop and go traffic. It was running fine. Now that school is out and I finally have time to work on it I am finding all that is wrong with it.

The most immediate problem is that it has an idling problem that is perplexing me: WITHOUT the AFM it runs, however rough. I found this out because I swapped it from another working car and forgot to plug it in before I started. I even went as far as checking some of the vacuum lines before I realized that I hadn't plugged it in yet. However as soon as I plugged it in, engine cut immediately.

I can get it started if I hammer the gas right after the starter motor stops.

I dunno... I did a brief search but to no real avail, the ICV is humming right along and checks out according to my meter and I can smell gas so I don't suspect either pump or ICV...

Vacuum leaks? Bad gasket? It's marginally warmer today than the day I bought it...

Any help would be hot. :up:

Thanks.

[John Smith]

http://youtu.be/ArJ_i7WX0wo

[TurboJake]

Your check engine light never turns on. Consider replacing the bulb in there. Get a 173 DME in there if you don't have one. Then try the stomp test.

[SmokeE30]

87 is to old to tell you that much with a stomp test but yea start by getting the check engine light fixed and also check for vacuum leaks via smoke test to really be able to tell

[John Smith]

Thanks guys. Any ideas as to why it at least runs when the afm is disconnected? The video was with the afm connected.

[MrBurgundy]

Carb choke all the air hoses, check if there's a leak.

[dnguyen1963]

Thanks guys. Any ideas as to why it at least runs when the afm is disconnected? The video was with the afm connected.

Car is running on preset air/fuel ratio when AFM is disconnected.

[MJCRO]

Check for vacuum leaks, then go from there.

[jlevie]

With the AFM disconnected, the DME defaults to a rich fuel mixture. But with the AFM connected the DME bases fuel flow on the airflow as measured by the AFM. When intake are present there is more air entering the head than indicated by the DME.

Have a shop run a smoke test to find the leaks and repair as indicated.

[John Smith]

Thanks to all.

Just bought some nasty cheap cigars and am gonna run a smoke test today.

[jlevie]

You can try that, but to do a proper smoke test you must plug the exhaust, and replace the AFM with a plug and feed smoke in someplace else or replace the AFM with an adapter for smoke introduction. The feed in smoke until a pressure of 2-4psi is reached and hold that pressure for at least 5 minutes.

[shadowracer]

Use the small vacuum hose that goes from the side of the intake manifold to the fuel pres. reg. after you plug the exhaust, and afm to introduce the smoke, just make sure you pull the hose off the reg. not the intake.