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jeffpatch
02-04-1999, 01:55 AM
My 86 325es has come down with an idle problem recently. It likes to jump around (when warm).<br>It usually idles at around 1,000 and now it jumping between 1,000 - 1,500 and the needle on the MPG gauge is flying back and forth... Runs fine when<br>I'm moving though, it just happens when I'm at a stop light.<br>My dad suggested a case of "bad gas". I recently put 87 octane gas from ARCO... my usual gas because it's cheap and I don't have a job so I'd like to get as much gas as posible for little money. <br>I ran down the gas in the tank to near empty (~6 litres left) and filled up with 89 octane from Chevron. But it's still happening. I'm sure some of the old gas could still be in there so when this $2 worth of gas is gone I'll fill the hole tank up with 91 octane or whatever # it is. <br>Other than the gas, does anybody have any other suggestions on why this would be?<br>I read of a idle control valve that could be causing this, I read a test for it also, with a drilled penny. I'll try it if it's not the gas.<br>I also installed a K&N drop in air filter a couple months ago if it makes any difference.<br>TIA<br>Jeff Patch

Ino
02-04-1999, 12:48 PM
Jeff,<p>You are killing me over here. You need to stop the cheap gas and go for the premium stuff. When I got my car 6 years ago I did the same thing. My mechanic noticed the rough idling and asked me what I was putting in the tank. He suggested to run Chevron on it (super unleaded). <p>These cars suffer from carbon deposits so you need to keep you intake system clean. <p>I would check with the 02 sensor, and then check the idle val. If you have a defective idle val then replace it. If you don't then it will eventually cause the idle units to go bad and then you are looking at bucks (I think $200-$300) I can't remember.<p>When did you perform a val adjustment last?<p>Ino<p><br>

jeffpatch
02-04-1999, 09:06 PM
I got a valve adjustment the day after Thanksgiving... less than 5k ago.<br>How do I go about checking the o2 sensor? I know where it is but how do I know if it's bad?

Callan
02-04-1999, 10:12 PM
Your idle stabilization system is going out once the car warms up. By saying that things were fine while off idle you already are half way toward diag. the problem. The idle control system shuts off once the throttle is opened enough to turn the microswitch at the throttle off. The problem most likely is a bad control unit which is in the glove box next to the fuel injector control unit. <br>The penny test you wrote about isn't that conclusive so try to find a friend with a good idle valve to test on your car. Install the tast valve & if things are perfect at all times you'll need an idle valve & not a control unit. If the valve didn't help once the engine got warmed-up you are probably looking at a idle control unit.<br>There are a few inputs to the control unit to check with a multi-meter if you are up to it. Write back if you want to check these few pins out before spending any $$

Ino
02-05-1999, 10:53 AM
I would just simply buy one Jeff. <p>I guarentee you that within the next year it will go out. They usually last about 2-3 years. Take or give.<p>It's always good to keep a spare. I am not sure but I think they are about $20. I could be wrong but its nominal.<p>Ino<br>

Paul
02-10-1999, 12:46 AM
<i>: My 86 325es has come down with an idle problem recently. It likes to jump around (when warm).<br>: It usually idles at around 1,000 and now it jumping between 1,000 - 1,500 and the needle on the MPG gauge is flying back and forth... Runs fine when<br>: I'm moving though, it just happens when I'm at a stop light.<br>: My dad suggested a case of "bad gas". I recently put 87 octane gas from ARCO... my usual gas because it's cheap and I don't have a job so I'd like to get as much gas as posible for little money. <br>: I ran down the gas in the tank to near empty (~6 litres left) and filled up with 89 octane from Chevron. But it's still happening. I'm sure some of the old gas could still be in there so when this $2 worth of gas is gone I'll fill the hole tank up with 91 octane or whatever # it is. <br>: Other than the gas, does anybody have any other suggestions on why this would be?<br>: I read of a idle control valve that could be causing this, I read a test for it also, with a drilled penny. I'll try it if it's not the gas.<br>: I also installed a K&N drop in air filter a couple months ago if it makes any difference.<br>: TIA<br>: Jeff Patch<p>Jeff<p>I just bought a 89 325is from a BMW mechanic. The day after the purchase the idle started going crazy....jumping from 1000 - 1500 rpms when I was at a complete stop.<p>I drove the car to the mechanic and he instantly said it was the idle control valve. It took him about 30 seconds to install and it fixed the problem instantly........I instantly thanked him and took off before he talked me into paying for the part. (around $200)<p>I have an i motor and you have an e motor. I know their are differences but I'm certain it's your idle control valve........mechanic said the penny trick isn't a good solution.<p>Let me know if you have any questions<p>Paul<p></i>

Ed
02-10-1999, 05:25 PM
My 1986 325es and my 1985 318i both did that. It is either the idle control valve, or the idle control module. If it is the module, you may be able to take it apart (wedge paper clips around the tabs) and just replace the transistor. Bad gas has NOTHING to do with this problem.


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