Jump to content

Pinto Idle Valve


Guest Bob

Recommended Posts

It's an idle air (bypass) control valve, standard efi sierra. With fuel injection there are two common ECU strategies for controlling idle speed. One is with an IACV. The computer sets idle fueling and target idle revs and maintains them by varying airflow through the IACV (commonly with a pulse width modulated signal), not with the butterflies. (The other strategy is with varying spark advance and retard.)

So all injected sierras had something like that.

 

Nigel

Link to comment
Share on other sites

Yes, I've got an unused one and was wondering what to do with it.

The plug exits out the rear and not at right angle as seen on the ebay ad.

Came from the black top zetec engine inlet manifold so may be slightly different?

 

Simon.

Link to comment
Share on other sites

Guest Bob

Thanks guys.

 

So here's the problem.......usual idle 'hunting' when the engine warms up. Have already taken the valve off, encouraged it the behave by soaking it in white spirit, sprayed with WD40, refitted with gasket sealant and same problem. So then I stuck a meter on the incoming voltage and found the ECU is telling it to hunt. OK, so probably not the valve (dont know what tells the ECU to do that) but for 17 quid could rule the valve out. Assuming it's not the valve, what could it be?

 

Ta, Bob.

Link to comment
Share on other sites

Assuming the ECU is trying to tell the valve to behave itself and the valve is fully serviceable (and you can't assume the latter. Sticky IACV is a common problem) then the engine may have access to uncontrolled extra air. Another common problem is using the 'idle' screw on the butterfly to adjust idle so the butterfly is not at its correct idle position. It isn't an idle screw. It has a proper setting. That setting is closed at idle. The throttle pot and airflow meter can wear and cause problems for the ECU reading them. This occurs mostly at idle and small throttle openings/airflows cos this is where the engine spends most of its time. Both especialy the airflow vane can get gummed up affecting readings. Otherwise you are looking further for an air leak.

 

Nigel

Edited by Longboarder
Link to comment
Share on other sites

Mine "hunted" when I first ran her post installation. Firstly someone had dicked about with throttle stop screw and the butterfly wasn't shutting and secondly where the butterfly closes against the manifold there was a build up of crap, cleaned that off and a perfect idle was restored.

Link to comment
Share on other sites

Guest peter2b2002

My old efi used to sound like a boy racer reved up to 1500 then down to 700 tried everything new pipes cleand the valve nothing worked so i gave up just carried on soundinglike aboy racer

peter2b

Link to comment
Share on other sites

I once stopped at a pedestrian crossing, and at the moment the young girl began crossing my engine revved aggressively, due to dodgy iacv. She jumped about a foot vertically and ran back to the nearside pavement! I must have looked like an utter dick

Link to comment
Share on other sites

Guest Bob

Will investigate all suggestions after 1 week eating prosciutto and drinking a few glasses of Pinot grigio in Italy. Idle....idle.....idle,,,,,

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...