e30 323i strange idle

[Court M3 0]

My e30 323i has a strange idle. when I start the car it idles and then surges up to 2k rpm and stays there. Any one with ideas? Production date is 12/82 if that helps.

[QuickSilver 0]

idle control valve is stuffed, or theres a vacuum leak, or both, there are other reasons im sure but these are common, mine used to be weird, normal when started cold then once warm very high, was a combination of the idle control valve being stuffed and a vacuum leak

Edited December 20, 2007 by QuickSilver

[Court M3 0]

alright, will have to start checking vacumn leaks. My car does not have an ICV.

idle control valve is stuffed, or theres a vacuum leak, or both, there are other reasons im sure but these are common, mine used to be weird, normal when started cold then once warm very high, was a combination of the idle control valve being stuffed and a vacuum leak

[ducatiss 1]

It will (or should have) have an idle control valve located underneath the inlet manifold toward the firewall. On the pre-motronic they are activated by the engine coolant heating up a bi-metallic spring which then closes the valve restricting the extra air flow required during startup and cold idling. The ICV on the jetronics can fill with grunge - best replaced with a NEW one but you might get away with giving it a clean out if you can. From memory you can test them out by tipping hot watter down them and watch them close then gradually open as the unit cools down.

Edited December 22, 2007 by ducatiss

[QuickSilver 0]

if ur missing an ICV id say theres ur answer lol

[Court M3 0]

if ur missing an ICV id say theres ur answer lol

Nah got it down to the air slide valve. does anyone know if this can just be cleaned or bypassed? Guessing this is what ducatiss was referring to earlier. Part shown in pic.

If so then will do it this afternoon.

[*Glenn* 854]

Nah got it down to the air slide valve. does anyone know if this can just be cleaned or bypassed? Guessing this is what ducatiss was referring to earlier. Part shown in pic.

If so then will do it this afternoon.

You could try. But its best just to replace it. Then you will know its right. Also make sure that you have water flow through both hoses. Sometimes sedement blocks them.

[Court M3 0]

cool. Most parts places want $170US for them here with a 2-3 week wait though. Need to get the car running sooner than that

[Neal 545]

My e30 323i has a strange idle. when I start the car it idles and then surges up to 2k rpm and stays there. Any one with ideas? Production date is 12/82 if that helps.

Had the airlow sensor / meter replaced on my old e30 323i , whas doing the same thing , fine from 2- 6krpm , A real pig below that.

[Court M3 0]

swapped out AFMs also. going to work on bypassing it tomorrow.

[ducatiss 1]

swapped out AFMs also. going to work on bypassing it tomorrow.

I'm not sure if there is any point in by-passing the idle control valve. For one thing you will have to reconnect those water hoses which is a pain, and the other thing is that the car will never idle correctly. When the engine is cold, this allows more air to be drawn into the engine thereby compensating the idle speed. As your engine warms it progressively shuts off the air. What you will end up with is either an engine that idles correctly when cold and incorrectly (ie high) when warm, or vice versa depending on where you set your idle speed.

My suggestion is to attempt cleaning and then check the unit by using hot water to see that it closes. If it doesnt, you will need to replace it. You will be unlikely to find an e30 jetronic one in the U.S. Price one in NZ or look for a good 2nd hand unit (quite difficult as most of them are stuffed by now though I was lucky with mine)

Edited March 1, 2008 by ducatiss

[Court M3 0]

cool since the car is down anyway right now, will try that today.

[Court M3 0]

Tried the hot water today and it closed and opened like it was supposed to. Did notice however that the hose on the intake side was wet and after taking the valve off coolant side was blocked with a bunch of crud. Wouldn't this passage be a straight through to let coolant circulate? Is there anyway to clean this part out? Tried brake parts cleaner, and carb cleaner

Thanks this board has been quite helpful.

Edited March 2, 2008 by Court M3

[ducatiss 1]

not sure what you mean exactly about what is blocked, but it is hopeful news that the valve actually opens and closes as it should. Also not sure on what you should clean it with - something that comes to mind is drain cleaner! Just make sure it doesn't eat into the alloy. I haven't tried this myself but would be worth a shot. You could also try chipping away at it with whatever you can poke in there. The only other thing that comes to mind is radiator cleaner

Edited March 3, 2008 by ducatiss

[Court M3 0]

yes air valve opens and closes. looking at the pic, the two hoses on the left are for coolant. Don't know if coolant is supposed to flow through of if there is a temp sensor or something between them.

[*Glenn* 854]

yes air valve opens and closes. looking at the pic, the two hoses on the left are for coolant. Don't know if coolant is supposed to flow through of if there is a temp sensor or something between them.

Water should flow through the two hoses on the left. Use compressed air and gently blow through them and check if they are blocked. The hoses normally block at the engine end. Take them off there and make sure the fittings they are attached too arent blocked and the hoses arent blocked as well. Just use a small screw driver to unblock them.