My 1984 318i has idled higher than normal ever since its engine was switched out. At first, it was about 1500-2000 rpms, and lately its been getting worse, now idling at 2500+ revs. I am running a Big Bore throttle body, but have tried switching back to the normal one before. It makes a difference, but a small one. Any ideas are appreciated. Thanks! [bmwdance]
318 idle problems
- Thread starter Cody318
- Start date
CHeck and see if the idle control valve is still plugged in and getting signal from the ECU. Its a little thing that sits about the intake manifold, has two rubber pipes and two wires connected to it. And there is a small spot to fit a flat head screwdriver into, thats the idle adjustment.
Its either that, or the idle control module in the glove box. When one goes out, the other usually fries. The module is hidden up under the ECU I think.
Oh one last thing. Any big vacum leaks??? Intake manifold and throttle body sealed good? Air getting let into the engine will raise the idle, so make sure all your seals are good. It would have to be a bigger leak for that kind of rpms. All the idle control valve and madule do is let air in to keep the engine idling.
Aaron
Its either that, or the idle control module in the glove box. When one goes out, the other usually fries. The module is hidden up under the ECU I think.
Oh one last thing. Any big vacum leaks??? Intake manifold and throttle body sealed good? Air getting let into the engine will raise the idle, so make sure all your seals are good. It would have to be a bigger leak for that kind of rpms. All the idle control valve and madule do is let air in to keep the engine idling.
Aaron
I now suspect the idle control valve is faulty. Following instructions in the Bentley repair manual, I tested it and found no resistance. The meter reads 1.5 ohms, which is the same as when I put its 2 needles together on the same resistance scale. The adjusting screw didn't change this reading, and according to the manual its supposed to have 8-10 ohms of resistance, so I'm looking to replace the unit. Would you reccomend replacing the module in the glove box as well?
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Yes I would try to replace them both at the same time. There might be a way of testing the module, look in the bentley.
I dont have an extra one. I checked but I removed the idle module some time ago off my bars car 318i. If you want you could just open the throttle valve a little, well on the stock throttle body there was a small adjustment screw that you could turn in and crack open the butterly in the throttle body. LOL just like raising the idle on a carbuerator, but more difficult to get at. If you did this you would need to remove the idle control valve and plug the holes. I would recommend fixing it the right way and buying the parts. I
t wont be that cheap either... see if any place online sells both the units together cheaper. I just checked prices at advance auto parts online and your looking at atleast $300 from them. Ouch, check the internet... look on ebay. A 84-87 325 module and valve might work.... check the bently.
I dont have an extra one. I checked but I removed the idle module some time ago off my bars car 318i. If you want you could just open the throttle valve a little, well on the stock throttle body there was a small adjustment screw that you could turn in and crack open the butterly in the throttle body. LOL just like raising the idle on a carbuerator, but more difficult to get at. If you did this you would need to remove the idle control valve and plug the holes. I would recommend fixing it the right way and buying the parts. I
t wont be that cheap either... see if any place online sells both the units together cheaper. I just checked prices at advance auto parts online and your looking at atleast $300 from them. Ouch, check the internet... look on ebay. A 84-87 325 module and valve might work.... check the bently.