high idle, vacuum leak? solved!

[dubownerbilco]

i cant seem to get my idle down to a normal speed, its currently at around 1400rpm

i have tryed cleaning out the icv, simply winding down the idle adjustment screw, there is slack in the throttle cable and i also sprayed brake cleaner all over the upper parts of the inlet that i can get it to, but could there be a leak from under the inlet somewhere? the 2 vacuum pipes that connect under the inlet are ok and fit tightly but should there be anymore?

or is there some common vacuum leaks with this engine??

or could be something else unrelated?

[leeparkes]

If you got an intake leak the idle will normally be rough.

[dubownerbilco]

It is hunting slightly but i wouldnt say it was rough

[Bristol_Jer]

What rev range is it hunting between?

[dubownerbilco]

1100-1500 i would say, the hunting has only started since changing the leads and plugs though, before that it was a steady 1400

[mcbonio]

Does the idle drop when you take the oil filler cap off?

Is your TPS adjusted correctly? Try unplugging it when the engine is running see how it behaves.

[walinsky]

There is a 3rd vacuum pipe underside the intake mani which should be capped when not using a carbon canister. It's located under the hose that runs to your icv.
The 3rd picture in jimboe39540i's fs thread http://www.e30zone.net/modules.php?name ... 51#2521351 shows the (capped) pipe perfectly.

[dubownerbilco]

Ahhhh that could be the one, i dont recall connecting anything to it!

I shall take a look in the morning

Thanks!

[dubownerbilco]

welllll, it turns out i had the wrong coding plug in the clocks,

or rather i had the right on for the original engine (4 cyl)

so i got a spare 6 cyl plug from a friend, and it is actually idling at the correct rpm!

doh!

idle is still a little rough, but this can be cause by the speedtouch chip, so after some use it may settle down