tasmin 3.5 flapper on a 4.2 stage 3 v8D ENGINE

[matt h67]

Hi all my problem is i cant get it to idle more than 4-500rpm,but if i remove aux air valve it runs faster ie to fast as expected..
is it poss that the standard flabber plenum cant supply enough air to this engine?idle screw is even removed ,,,

[ramon alban]

Hello Matt, because your engine responds to the air allowed in when you remove the EAV, one would expect it to do the same when the idle control screw is unscrewed and removed.

The probable cause is the idle air gallery from the air rail to the plenum interior is blocked with crud. This is a common fault and can be fixed, usually by removing the plenum and poking a stiff wire throught the gallery from the plenum inside. Even that is difficult because the gallery hole is not visible. If the plenum is removed, take the opportunity to clean the breather gallery too as well as cleaning and adjusting the throttle plate and linkages.

I understand it is also possible to drill out the gallery blanking plug and poke the crud out from the outside leaving the offending crud loose inside the plenum. It shouldn't be a problem so, your choice.

The PDF available from here may help.

If the idle air gallery is clear, then I imagine it could be enlarged if one has suitable information and access to workshop equipment.

[matt h67]

thanks for your reply will get on it asap and see if thats the problem