New missfire problem, please help

Ok, i changed over my throttle body and intake manifold yesterday and when everything was re-connected and tight, tried the car and is now idling very roughly indeed. It appears to be overfuelling loads, with lots of unburned fuel being dumped out of the exhaust, the fumes are very thick and black. The car seems to be "searching" if this makes any sense, it will increase the revs, and therefore the fueling for a few seconds, and then lean off and nearly cut out. It just keeps repeating this. Under revs there is a rough missfire.

The only thing we have found to make any difference so far is the right hand side (as you look at the engine) Throttle position sensor> By altering the position of this a little we can make the problem worse, but not better.

Any ideas what this could be??

Sounds like a visit to Hyper?

Sounds like a visit to Hyper?

Hoping i can avoid that if possible, could really do without the expense.

Gareth, look at the Map sensor and follow the Vac pipes and make sure that they are connected to the FPR (Further along same side of the engine) and also the Manifold Reference outlet.

Also check to make sure the Vac pipes are not kinked within the area above.

Do not drive on boost until you suss out the problem mate.

See here,

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=13939&d=1112558977

Ive got an aftermarket FPR and my MAP sensor only has 1 vac outlet from what i can remember from last night. There is a "V" splitter that the boost controller has a pipe attaching to. Does this V attach to the MAP sensor and then the FPR pipe attach to that. Where does the regulator pipe attach??

Do you think its more likely to be vac pipe related rather than Throttle position sensors??

Ive got an aftermarket FPR and my MAP sensor only has 1 vac outlet from what i can remember from last night. There is a "V" splitter that the boost controller has a pipe attaching to. Does this V attach to the MAP sensor and then the FPR pipe attach to that. Where does the regulator pipe attach??

 

Do you think its more likely to be vac pipe related rather than Throttle position sensors??

I think it's more likely due to a faulty vac pipe within the right hand side of the engine where the map sensor is located. Just make sure the Manifold reference outlet, MAP sensor and FPR Vac lines are not leaking or kinked and are on securely.

It would be wise to carry out a fault diagnostic.

Im assuming this is deffinately the case with a single turbo instead of a TT yeah? Ill ask my mate to give it a go, he's looking at the car at the moment.

My friend who is looking at it seemed to think it was electrical and the only main electricals around there are the wiring loom from the Ignitor that goes behind the dip stick. He moved that a little and now the car wont start at all so looks like we may have disturbed some wires when taking the old manifold off, bummer. Got an auto electrician coming out on Thursday to have a look.

Gareth, get the Electrician to have a look at the FCD wiring also, just in case.

Gareth, get the Electrician to have a look at the FCD wiring also, just in case.

Will do cheers.

bummer. Got an auto electrician coming out on Thursday to have a look.

oh no, not bloody again...