hi lads i need a bit of help here . just bought a 2wd cos again the problem is it idles eratic and when driving on low revs it is like a kangaroo. on a run with the revs higher it is ok but when you slow down again it seems to be hunting up and down . any suggestions many thanks

 

is idle revs stable?

 

well it doesnt cut out. also next to the inlet manifold there is an oval shaped thing? with a plug fitted into the top which actually isnt connected. when i do connect that it makes it rev up and down on its own. sorry about the oval thing but im unsure what it is, bronze in colour alluminium i think?

 

do you mean this pic is from 3dr cossie, but there should be one in 2wd too.

if you mean that, take that valve of, clean it up very good, oil it whit gun oil or something thin oil. put valve back in and connect the wire. now try again.

note. there are 2 sprigs in that valve. and you must measure the little nut in the valve, so you can put it back to same position and lock whit a bit of paint or threadlock or something similar.

 

thats the one, i will do that now and see if it makes a difference, i have put a thread about this problem on technical Q&A UNDER WHATS WRONG?? have a look as i have put a bit more info on there about the car . many thanks 4 now

 

i think it is Idle valve. about 85% sure.

 

i have taken out the idle valve and give it a clean and there is no change. its just hunting like mad.

 

Mine used to rev and idle at 3k when i had the idle valve plugged in, if i unplugged it it sat perfect just under 1k. I thought it was the valve that was no good, but when my engine was rebuilt i was told it was caused by a gasket (cant remember which, sorry) not the idle valve.
(I had cleaned it too and it made no difference) Soon as the new gasket was on it was fine again

 

cheers mart, just hope it wasnt the head gasket!!!

 

you did put that connector on too? was the O-ring in good shape, in idle valve? is there air leakage, in your air inlet manifold? try to find out it by spraying starter spray or somethin similar, in in your inlet manifold. if there is change in behavior of your engine, there is an air leakage. maybe one of your air inlets seals is leaking.

 

cheers ill try that.

 

There is also an air adjustment screw under the throttle you can give the engine more or less air at idle i think you need to give it some more air at idle.
But it could mean you also have to adjust the mixture at idle.

 

Definitly wasnt the head gasket, its inlet manifold gasket im sure

 

better give the wife bad news, i need a set of greens 3 bar map sensor T34 oh and a RS500 intercooler and it will work then!!!

 

In my opinion it could be a number of things!

1) Air leak around inlet manifold/anywhere after throttle body
2) Idle Speed Control valve (as discussed above)
3) CO setting on the ECU has been messed around with (mine had a very similar problem and this was the cause, get it to a specialist as if it has been turned down to pass an MOT the car will run lean throughout the rev range and could melt!)
4) Another sensor has gone funky, could be coolant temperature sensor or throttle position sensor.

Most likely to be 1 2 or 3 in my opinion!

 

cheers phil, i am gonna book it into interpro tomorrow and get it sorted asap. i think its a air leak somewhere had a look earlier had a mess around in that area and she would hunt and then stop but i couldnt find exactly where the problem was, MELT!! best i take it easy for a while until shes set up . thanks again

 

so you tested for air leak and there was one? replace the seals, and it will be ok. no need for specialist, if its just air leak.

 

well im going to add some goodies on anyway and i would rather be safe if u know what i mean..... cant take any risks