High rpm's at idle - United Bimmer Community

**mzbmw325i** · 10-16-2007, 12:34 PM

Hi,

On my 88 E30 325is, the rpm during idle stays around 1k. the guy that sold me the car said he replaced the ODB and told me the rpm is fine. i do see it on the receipts that it was replaced but it still bothers me that it shows rpm at 1k

i cleaned the ICV valve, spark plugs are new, no vacuum leaks that i know of.Hoses are new.

any ideas, could it be the ECU, TCP or really the board reads the rpm high/wrong, how can i test it? thanks

**elsabor67** · 10-16-2007, 03:41 PM

From experience (just went thru this) I would recommend that you find the same ecu for your car(last numbers 153 or 173). Connect the test ecu and if your rpm's drop to normal, swap your ecu. That was the way I found out mine was bad. Before you do that check your vaccum lines and lines. Good luck.

**mzbmw325i** · 10-17-2007, 12:08 AM

Quote:

Originally Posted by elsabor67

From experience (just went thru this) I would recommend that you find the same ecu for your car(last numbers 153 or 173). Connect the test ecu and if your rpm's drop to normal, swap your ecu. That was the way I found out mine was bad. Before you do that check your vaccum lines and lines. Good luck.

where did you get the last numbers 153 or 173. under what year E30 did you see it?

like i said hoses look fine, i have a little oil leak from my valve cover gasket, i don't know how much can that contribute to the high rpm.

**elsabor67** · 10-17-2007, 01:24 PM

[QUOTE=mzbmw325i;154011]where did you get the last numbers 153 or 173. under what year E30 did you see it?[QUOTE]

The numbers i mentioned are the last 3 numbers on your ecu. I got it from a search I did and it landed me on a bimmerboard forum page. I sent you a PM with all the ECU numbers that apply for BMW 325i from 87-91. The oil leaks should not affect your rpm's. If you need anymore help you can shoot me a PM and let me know.

**jcjdavis1** · 10-19-2007, 11:59 AM

Hi Slacken off small nut then wind back large knurled screw using plumbers grips to hold cable and that might lower idle speed.It worked for me.

**mzbmw325i** · 10-22-2007, 08:52 PM

i did the stomp test tonight and i got no reading back, the check engine light did not blink once. what does that mean?

**celsdogg** · 10-22-2007, 09:27 PM

^^^ i believe that means that your not throwing a code. but the obd1 isnt as sophisticated as obd2.

**mzbmw325i** · 12-10-2007, 01:46 PM

ok, i still have the issue with high idle. i checked all hoses, replaced ECU, tested ICU valve, all good as far as i know.

i am thinking to check the TSP switch, is it possible if that is shot that may cause the high idle. Maybe also the AMF.

where can i find out at what rpm the auto tranny is supposed to shift gears. currently my 4th gear shifts at 50 mph/ 3k rpm, i think it has to do with my high idle or something.

thanks

**Exilion** · 12-10-2007, 02:26 PM

Quote:

Originally Posted by jcjdavis1

Hi Slacken off small nut then wind back large knurled screw using plumbers grips to hold cable and that might lower idle speed.It worked for me.

Actually that worked for me. I've heard sometimes it doesn't help though but I think that's only when your idle speed is jumping around. Basically it'll adjust the default position of the throttle valve.

**mzbmw325i** · 12-10-2007, 03:16 PM

Quote:

Originally Posted by jcjdavis1

Hi Slacken off small nut then wind back large knurled screw using plumbers grips to hold cable and that might lower idle speed.It worked for me.

My idle is steady at 1k, can't see the picture, can someone show a pic with the nut in question. thanks.

**elsabor67** · 12-10-2007, 03:57 PM

My advice, I wouldn't do any adjustment to the throttle cable. Just my 2 cents.

Get a bentleys manual and do the current adn electrcial checks for the TPS. Also, Check your MAF sensor too just in case. Also, if your check engine light isn't coming on at all (even when you turn the key to start the car) then you bulb might be out.

**Exilion** · 12-10-2007, 03:57 PM

hmmm... I can describe it for now. You'll see a cable coming to the intake manifold. At the end of this cable is a bolt that you can either tighten or loosen with a slot screw driver which in turn increases or decreases the engine idle speed. That's all I adjusted for mine, although I don't know if this will be a definite fix for you. Then again it's simple to undo so whatever go for it.

**player2poet** · 12-29-2007, 01:42 PM

hey did your issue with the idle ever get resovled im having the same damn problem now idles at 1k replaced icv, idle control brain little green box next to ecu ,new intake boot,checked tps seems to be working ,adjusted all i could made run at seven hundred rpms but it searches the whole time at idle but as soon as i drive it the stinkn idle goes right back to 1k what the hell thing ran fine a week ago ,any ideas?

**mzbmw325i** · 12-29-2007, 10:29 PM

no, i have not and is bugging the hell out of me, i unplugged the ICV while the car was running today and the rpm did not even move, so i assume maybe the ICV is shot, i am going to the junk yards to scavenge one and go from there.

i know i don't have a vacuum leak so i am going to start with the ICV and go from there.

**kenika65** · 12-30-2007, 12:01 AM

Sounds like a vacuumed problem or your ICV, AFM, ECU, FPR, TPC... well you get the picture.

Try this out.

http://opel-scan.ru/files/DME_1.1_1.3.pdf