Uneven idle but getting better.

[Wid77]

In my continuing attempts to smooth the idle on my '88 325i i have now confirmed (as best i can) that there are no air leaks in the rubber hose from the airflow meter and around the intake system generally. I cleaned with carb cleaner at the weekend. I also changed the air filter. The revs are now quite stable (about 800rpm) but it is still not what i would call smooth and it makes it a bit difficult when driving in traffic. When you put the engine under load there is a hesitation.

My plan of attack is:-

1) Check rotor arm & distributor cap & replace if needed.
2) Clean idle control valve
3) Replace blue temp sensor (it's a bit hard to get at isn't it!)
4) Get mixture checked

Do you think i am going about this in the right order?

Thanks

[DazzyA]

I've got the exact same problem with mine and my AFM is missing the co tuning screw. Maybe you sould get that done first mate. good luck.

[Wid77]

Thanks for that mate. Will have a look and see if it is there.

[max_crox]

Not sure if this helps or not..
But I was having the same problem with my car.. the idle was all over the place. The garage replaced the throttle switch and it is perfect now, they did replace the plugs and oils as well which helped a lot too. The guy said that this thing is responsible for the revs when idling and it switched to another position when its not and it was faulty which is why the idle was all over the place.. This is just my interpretation of what he said so I might be talking total crap. but I think that was the gist of what he was saying.

I think the part was 13 63 1 710 559 its on the throttle housing assy diagram if you have ETK
or here item 2 http://www.realoem.com/bmw/showparts.do ... g=13&fg=15

Sorry if Ive written total BS

[Brianmoooore]

Not sure if this helps or not..
But I was having the same problem with my car.. the idle was all over the place. The garage replaced the throttle switch and it is perfect now, they did replace the plugs and oils as well which helped a lot too. The guy said that this thing is responsible for the revs when idling and it switched to another position when its not and it was faulty which is why the idle was all over the place.. This is just my interpretation of what he said so I might be talking total crap. but I think that was the gist of what he was saying.

I think the part was 13 63 1 710 559 its on the throttle housing assy diagram if you have ETK
or here item 2 http://www.realoem.com/bmw/showparts.do ... g=13&fg=15

Sorry if Ive written total BS

Completely correct, and one of the first things to check.
First of all, listen carefully to hear if it clicks with the throttle just off fully closed, and then remove the air hose, unplug the connector and check it out with a meter. Pins 1 and 2 should be short circuit ( zero ohms) with throttle closed, going open circuit when throttle slightly open.
Pins 1 and 3 should be short circuit untill the throttle is about 2/3 open, when they go open circuit.

[max_crox]

Cool... I even sounded like I knew what I was talking about..
If it is that you can get a direct replacment from Bosch (i think thats where he said he had it) for about 40 quid or you can get one from GSF for about 30.

[DazzyA]

Nice one, I shall have a look at the weekend.