I think this may be a vacuum problem - though not sure. Car hesitates, idles rough - surging between 500 and 1500 rpm - and eventually dies at start up when cold.

As soon as it is up to operating temp - about 1/2 on temp gauge - the idle smooths and car will run near perfect until it is shut down and cools.

Wanted to park the car for the brutal prairie winter and thought I'd try to track this problem first.

Thanks for comments/ideas. Still climbing chinese mountains.:D

Dale

Hmmmm, if it was a vacuum issue it wouldn't go away when the car is warm.

Could this be:

1. warm up regulator
2. cold start valve

Rob

Thought I may have had a leak but a check of vacuum and other hoses shows no noticeable cracks, loose connections etc.

Thanks for the tip on the WUR and cold start valve. Maybe try tomorrow - other cars requiring atttention for today.

Will have a look at the manual for your ignition switch thing tonight too Rob and get back to you.

Cheers
Dale

OMG, everybody just lay off the poor little cold start valve! It never wronged anybody! It's maximum time of operation is 8 seconds per startup so any problem lasting past the first 8 seconds is completely unrelated to it. You should check out your aux air valve.

OMG, everybody just lay off the poor little cold start valve! It never wronged anybody! It's maximum time of operation is 8 seconds per startup so any problem lasting past the first 8 seconds is completely unrelated to it. You should check out your aux air valve.

Damn - aux air - I was trying to remember the name of that one. I think the metal strip has a habit of failing. I believe a good test for that is the freezer to see if the little gate inside closes.

Where was that site that had all the pictures of all the regulators etc. on it? I saw it posted here before. I'm trying to make sense of the aux air, the wmr, etc......pics are great and much easier for locating the crap on the car. Thanks.

anyone know what I"m talking about?

OMG, everybody just lay off the poor little cold start valve! It never wronged anybody! It's maximum time of operation is 8 seconds per startup so any problem lasting past the first 8 seconds is completely unrelated to it. You should check out your aux air valve.

+1.... I'll put my loot on the WUR (if the vac lines are tidy)....I got a new one on ebay for $70 and it seemed to fix many idle/CS issues.

josh

Is this (http://www.lexam.net/peter/carnut/320parts.html) the site you were talking about?

My son and I chased all of the areas mentioned with his rough idling (no cold start issue). It turns out his timing was way too far advanced. When we backed it off, you could hear the "sweet spot" as the timing was adjusted properly. Now his idle is super steady at 1100 (was 500-1500 before)
My car was just the opposite! The timing was not advanced far enough, and I had cold start issues. They have been nearly eliminated now, and I can tell by the way the fuel accumulator fills initially that it is the fuel line check valve that is stuck open.
My bet is that replacing that valve (somewhere around $8-11.00 at autohausaz.com) and verifying your timing will solve your problem. We moved my distributor clockwise nearly 3/4 of an inch. Previously, the idle was fine, but now the idle is even smoother, and it starts right up if I drive it every day. (I have the fuel check valve, but haven't replaced it yet since it gives me a reason to drive the car all the time!)
Best regards,
Tim

Hey,

One other thing...which the purists may not like...my son and I both put a couple bottles of the fuel injector cleaner in our tanks, and it definitely helped!

Tim

My son and I are working on newly accuired 79 320i, and had all these warm start, cold start , idle issues too.. as a direct result of this forum, which has been a tremendous help, we just replaced the fuel pump & accumulator, filter, and it has seems ALOT happier. May have just been the check valve will never know now, but heck, it's all 28 years old and I ain't mess'n with it. We got new WUR and thats next. I'm convinced, in a very short period of time, these units are VERY vaccum, fuel system delivery sensitive.

Thanks to all in this forum for your help, If we were still fumbling thru the Haynes book, it would not happen.

Mark

Does it only do this on cold start????!!!,
this started to happen to my car about 3 months ago. it would rev between 500-1500 and eventually stall after the WUR dropped back.

i pulled apart the air intake system, an the whole system aswell as all the pipes where clogged with thick oil muck. cleaned it out, an all was FIXED. Installed pod filter system so it wasnt sucking hot crap air from the engine anymore.

so check your air intake pipes and system!

let us know wat happens anyway

cheers

Is this (http://www.lexam.net/peter/carnut/320parts.html) the site you were talking about?

yeah that's it, thanks! Just what i was looking for.

Yes, cleaning the air intake is key. Both my son and I have re-routed the "vent" hose off the top of the valve cover and plugged all the other hoses. The cars run much better! You can barely reach in and clean the "valve"...it is nearly as far as you can reach in and up. Rather than take it all apart, we used a rag soaked in a solvent that cleaned it all up...something I forgot to mention in the last reply
Best of luck!
Tim