Another E30 Idle Problem

[jamesthevaliant]

changed the plugs to single electrode bosch platinums.....big difference when the car is warm, but it still exhibits the same symptoms... O2 sensor and valve cover gasket are on their way and I will install them on tues. I'll let you know.

[Wayne 962]

Valve adjustment - our latest addition to the tech article pile:

http://www.pelicanparts.com/bmw/techarticles/E30-Valve_Adjust/E30-Valve_Adjust.htm

The procedure is not difficult at all!

-Wayne

[Jared at Pelican Parts]

One other things to check,

Coolant temp sensor, believe it or not, this sensor does affect the operation of the OBC, and can cause the idle to go crazy.

Did you check the resistance between the terminals on the Throttle Switch? It is directly below the throttle housing.

[Wayne 962]

The valve adjustment shouldn't take you more than an hour to do...

-Wayne

[jamesthevaliant]

Sorry for the delay... I went to Miami for a week, and now I am back home in cold dirty jersey!
I changed the o2 sensor, and every last vaccuum hose... and I can definatley feel a difference, but the symptoms are still there: it hesitates/ bogs out when it is cold (25F in the morning) runs great when warm...... but with a rough idle.
Coolant temp sensor...valve adjustment......huh?..... keep making suggestions.
I figure that if I slowly replace or adjust every part of this motor I will eventually have a happy BMW.

By the way, I just ordered control arms, bushings, sway bar links, and tie rods...is there a tech article?

Jim

[Jared at Pelican Parts]

Jim,

bushing overhaul tech article is in the planning stages. (I have a suspension squeak coming from somewhere, time to address that)

If you are still seeing a problem with the idle, I think you are correct in assuming the coolant temp sensor. Before the oxygen sensor has warmed up, the engine depends on the coolant temp sensor as well as the other sensors to provide the fuel injection computer with signals needed to regulate the fuel-air mixture. When the O2 sensor warms up, either by exhaust heat or heating element, it takes over control from the other sensors.

[jamesthevaliant]

Okay, Jared.......coolant temp sensor...after consulting the Good Book, I am reading all about the check and replacement procedure for the coolant temperature sending unit. Is this what you are refering to as the coolant temp sensor?

[Jared at Pelican Parts]

yes, exactly. It should be located in the thermostat housing.

[Peter Mathern]

My idle control valve was intermittent on my '89 325is, and caused similar problems. On some cold days, you could hear the valve trying to work, but you couldn't feel it vibrating. Tapping on it would get it working again and the car would work normally. I replaced the valve, but it sounds like some people have had good results cleaning theirs.

[Jared at Pelican Parts]

You may also want to try cleaning out the idle control valve. From what i've heard, BMW dealers would take the valves and spray them full of brake cleaner, then drain it out until the cleaner appears clear. Basically, the valve eventually gets clogged up with oil mist residue from the valve cover breather hose. Sometimes, this impedes the valve from opening and closing. Just be sure to let the valve dry out before re-installing. Some brake cleaners contain zylene or naptha which are both extemely flammable. Some even contain ether in the propellant, which is also used as starting fluid in carbureated cars. You dont want this stuff going down into the cylinders. it would be very bad for the engine.

[jamesthevaliant]

Jared, I have already cleaned out the ICV, but I used a carb cleaner. This didn't seem to help much. I am picking up my car today from the mechanic.....he found a used ECU to fix my little electrical mishap. I also had him test the coolant temp sensor while he had it, and it was bad. Ispoke with him this morning, and he said that after changing that sensor, the car runs and idles wonderfully. Some good news at last! I will let you know as soon as I get it back and drive it.

[Jared at Pelican Parts]

Glad I could help.

[jamesthevaliant]

Jared.......many thanks. New coolant temp sensor installed- problem solved. Jim-

[Jared at Pelican Parts]

I just finished a tech article on how to chenge it out yourself. Im sorry I didnt get it to you quicker.

[jamesthevaliant]

I would have done it myself, but my car was already in the shop having neurosurgery, so.........

[Jared at Pelican Parts]

You know, when you think baout it, neurosurgery is not all that different from working on cars, just that a surgeon has to keep it running while he's working on it. Someday in the future, Im sure we will have DIY brain surgery. just like those people who believe in trepanation.

[jamesthevaliant]

don't go drilling any holes into your head just yet.....

[Wayne 962]

The coolant temp sensor made my truck run rich for the longest time. Of course, it required removal of a ton of stuff to reach it!

-Wayne

[gott]

Just a note to anyone reading the thread. Some of the items replaced, like the O2 sensor, should give a check engine light on this car.

--Gregg

[bar1202]

Well I could be wrong but sound to me that you could have a bad head temp. sensor.