Another idle thread

[SEdgell]

Two weeks ago I adjusted my valves on my 86 325es. I had to replace the vacuum hose that runs from the throttle body to the valve cover, it split while I was taking it off. After everything was back together I've been having idle problems. It will fluctuate between 550-650rpm, and when I rev it it will die out while trying to get back down to idle, and when pushing the clutch in to stop. I went back and tried searching for vacuum leaks, but I haven't found any yet. Today I finally got around to cleaning the ICV, I let it dry for about 8 hours, reinstalled it and now it fluctuate between 1800 and 1900rpm. I'm lost, any help?

[Kershaw]

get it smoke tested. only way to be sure you dont have a vacuum leak. and it sounds like you do.

[SEdgell]

I've never heard of that, can you tell me a little about? I've been meaning to get some starter fluid and search for a leak that way.

[SEdgell]

Anybody have any other suggestions?

[Ryann]

You can find vacuum leaks at your local old school do-it-yourself carwash. Leave the car idling, pop the hood, put in some quarters, and set the wand for rinse (water only). The wand at the place up the street from me sprays a very fine low pressure mist WITHOUT having to pull the trigger. This is what you need. "Wave the wand" over suspect areas and listen for dips in idle speed. Repeat as required until you've isolated a specific area. Drive home and start digging. I have located and repaired vacuum issues like this successfully on several vehicles including a VW Rabbit and a Mercedes 380SEL.

[SEdgell]

Update: Saturday I adjusted my TPS and it got my idle down to around 12-1300 rpm, and then it started jumping up to about 1500. So yesterday I went and got some RTV and put some on the throttle body gasket and the valve cover gasket. Doing this got my idle down to around 1000 rpm, and then it started jumping between 900 to 140rpm. Any thoughts?

[Adrian_Visser]

Did you use a new valve cover gasket and torque your valve cover nuts tight and in sequence?

[jlevie]

Find a shop that can run a smoke test on the intake. Well, that or you can replace every hose, seal, and gasket that can result in an intake leak.

[SEdgell]

It's a new valve cover gasket

[Cha Ching]

It's a new valve cover gasket

Do you mean this is what caused your idle fluctuations?

[SEdgell]

It was after we adjusted the valves that the idle started jumping around, and then after I cleaned the ICV is when it got really high.

[z50_Jumper]

Any updates? I'm experiancing the same issue currently. Car runs great just won't idle under 900 to 1100 rpms.

I replaced the ICV and throttle body/TPS with known working parts. New temp sensor, found and fixed intake leaks. Infact I noticed when I remove the oil cap the idle actually drops a bit.

I also wanted to mention my throttle and ICV adjustment screw are all the way closed.

[jlevie]

At the risk of being redundant, find a shop that can run a smoke test on the intake. There are several places that can result in an intake leak that can't be tested by car cleaner. And keep in mind that several small leaks (that won't respond to carb cleaner) add up to a big leak.