idle speed

[karlos]

hi folks just joined the site! i am currently in the process of restoring a 1986 e30 316 for my daughter but every time i fire her up the engine revs at 2500 and wont come down . Does anybody know what could be causing this and how i could rectify it any help would be greatly appreciated cheers

[darkhorse737]

Originally Posted by karlos

hi folks just joined the site! i am currently in the process of restoring a 1986 e30 316 for my daughter but every time i fire her up the engine revs at 2500 and wont come down . Does anybody know what could be causing this and how i could rectify it any help would be greatly appreciated cheers

overtight throttle cable/ cruise control cable?.... try to disconnect cables and see what your idle is.

if the same 2500rpm.... disconnect ICV. Notice any difference? if none, next suspect is TPS. Disconnect tht...

What is the RPM now.... still 2500RPM? or now normal?

Let me know and i will walk u through next step

[karlos]

hi darkhorse. whats the tps? was icv idle control valve

[darkhorse737]

ICV(Idle Control Valve) it's a cylindericl shaped valve sitting by your intake manifold-approximately 2.5" long by 1" in diameter. It has a 2 wire connector that can pull out.
illustration: http://i19.ebayimg.com/01/i/000/f5/55/4be5_2.JPG

TPS(Throttle position sensor) you'll find that under the throttle body. a black plastic piece under the throttle butterfly and is has a 5-6 wire connector.
illustration: eBay Motors: NEW Throttle Position Sensor e30 325 e28 528e e34 525i (item 220240805718 end time Jun-28-08 20:44:30 PDT)

**i'm not advertising these items... i posted them here for illustration purposes only :-)

[GrayZONE]

Sounds like the ICV mught be stuck or out of adjustment. If you disconnect the ICV and the idle drops you cna adjust it using the flat head screw located on the unit. What did you find out after you disconnected the throttle/cruise control cable? Did the RPMs drop? The TPS sensor (black box located on the bottom of throttle body) senses when the throttle body's plate is fully closed and when it's wide open. It has a three wire connector that you can disconnect. Us a multimetter set to OHMs... touch the leads to the middle and left connectors. You should read all zeros with the plate closed. Begin to open it, you should here a click and the meter 000 display should go away. Now release the throttle plate and let it close. Move your left meter lead to the far right connector. You meter should read 000 at wide open throttle and go blank when you let the throttle plate close back. If any of these setting are incorrect you will have to loosen the two screws and adjust the TPS.