idle problem

[93zk]

so on my 87' 325e I'm experiencing a high idle at around 2500 rpm. then after about 10 seconds it drops down to 1000 and goes back up to 2000 every other 3 seconds. could this just be my idle control valve? ill squeeze the hose and it will run like normal. engine runs very hot after only maybe 5 min of running like this. thermostat problems? checking the voltage to my battery runs at 12 volts. not 13 or 14. could the idle problem be caused from the alternator? also im running a straight air intake. no box. and the rubber elbow is a little caved in. any suggestions?

[e30Villain]

Sounds like the Coolant sensor in thermostat housing and your icv. By hot, how hot do you mean. E30s go to the 3/4 line when they are not moving. As long as its not above the third line, your good, although 5 minutes is a bit too early to be going that high.

[jlevie]

Sounds like the Coolant sensor in thermostat housing and your icv. By hot, how hot do you mean. E30s go to the 3/4 line when they are not moving. As long as its not above the third line, your good, although 5 minutes is a bit too early to be going that high.

If the cooling system, and especially the fan clutch, is working properly the needle should not go more than a hair above the half way point at any time.

As to the OP's idle problem, a dirty ICV and/or intake leaks are the most likely causes. Remove and clean the ICV and have a shop run a smoke test on the intake/block and fix the leaks the test reveals.

[dnguyen1963]

Sounds like the Coolant sensor in thermostat housing and your icv. By hot, how hot do you mean. E30s go to the 3/4 line when they are not moving. As long as its not above the third line, your good, although 5 minutes is a bit too early to be going that high.

You have got a big problem with your fan clutch or your radiator is about to take a crap. Temp should never go to 3/4. The only other time that the temp gauge goes to 3/4 with normal engine temp is when your SI board/batteries has gone bad.

[e30Villain]

You have got a big problem with your fan clutch or your radiator is about to take a crap. Temp should never go to 3/4. The only other time that the temp gauge goes to 3/4 with normal engine temp is when your SI board/batteries has gone bad.

If the cooling system, and especially the fan clutch, is working properly the needle should not go more than a hair above the half way point at any time.

As to the OP's idle problem, a dirty ICV and/or intake leaks are the most likely causes. Remove and clean the ICV and have a shop run a smoke test on the intake/block and fix the leaks the test reveals.

You guys are right. My mistake. My car does not reach the 3/4 mark I was speaking on behalf of other member's but looks like I mixed it up with the half mark.

[dougie30]

my 325e does this too! but some times it stayes reving at 2000, so fucking annoying so you think its a dirty icv, or a intake leak would make it rev up like this?

[Gregs///M]

my 325e does this too! but some times it stayes reving at 2000, so fucking annoying so you think its a dirty icv, or a intake leak would make it rev up like this?

Yup, clean the ICV and check for vacuum leaks.

[93zk]

haha so i must be retarded. it was my fuse that blew for the idle control.
question, how can i check for an intake leak with carborator cleaner. do i just spray it on and see if the engine revs higher? where exactly do i spray it? or is there another way to check for leaks without taking it to the shop

[UserError]

Carb cleaner can find some intake leaks, though it's nowhere near as effective as a smoke test. You should spray while the engine's idling, and hit every vacuum hose, fitting, gasket, and on the intake boot, though a visual inspection of the boot usually reveals leaks coming from there.

[dnguyen1963]

haha so i must be retarded. it was my fuse that blew for the idle control.
question, how can i check for an intake leak with carborator cleaner. do i just spray it on and see if the engine revs higher? where exactly do i spray it? or is there another way to check for leaks without taking it to the shop

www.scottykilmer.com and search for cigar smoke test.

[93zk]

thanks that helped a ton!