Idling

KaTonyMa · Post by **KaTonyMa** » Tue Apr 14, 2015 3:55 pm

Hi guys ive got the following problem

She is also choking when i press the throttle. Ive changed intake manifold gasket, pcv valve and MAP sensor. Any ideas what might cause this?

Post by **Merlin** » Tue Apr 14, 2015 3:57 pm

Is it idling like that from cold or when it is hot?

When cold it usually points to the FITV
When hot is is usually the IACV

Although giving both a clean and tightening up the FITV screw with do it good.

KaTonyMa · Post by **KaTonyMa** » Tue Apr 14, 2015 4:04 pm

Cold and hot. Ive tighten the screw on the FITV.broke one of my IACV connectors on the bottom and its bypassed. Do you think it might be that? Ive cleaned them both before but it was never that bad

Post by **Merlin** » Tue Apr 14, 2015 4:08 pm

You have bypassed the coolant hoses to the IACV but still have the electrical connector connected to the IACV? I would say that is a problem. Your IACV will not know the temp of the coolant and cannot adjust idle correctly.

KaTonyMa · Post by **KaTonyMa** » Tue Apr 14, 2015 4:21 pm

Ah right i get you! So guess ill need a new IACV. Will that cure the choking when i press the throtthle pedal?

Post by **Merlin** » Tue Apr 14, 2015 4:30 pm

It may well do.

mercutio · Post by **mercutio** » Tue Apr 14, 2015 4:54 pm

if the iacv never sees heat from the cooling system and the fitv works as normal they will be fighting each other wont they??

Post by **Merlin** » Tue Apr 14, 2015 5:00 pm

The FITV is not electrical and simply works off a thermowax plunger that expands and contracts with the heat of the coolant. Once up to temp the FITV should shut off and no longer be in operation.

The IACV is electrical and when the electrical connector is removed idle falls dramatically as there is no assistance from the IACV. If there is no coolant reaching the IACV it may think that the coolant is cold and tells the ECU to increase revs. The ECU senses that the engine is idling high and cuts the injectors, and the cycle of bouncing begins.

Post by **Merlin** » Wed Apr 15, 2015 11:52 am

Another thing, you can test to see if either the FITV or IACV is not working properly or you have a vacuum leak. Get the engine up to temp and remove the intake to get to the throttle body. There are two holes, the lower hole is the FITV, when the engine is warm and you block the FITV hole with your finger nothing should happen. If revs fall while blocking this hole the FITV needs tightened. Blocking the top hole should greatly reduce revs and should try and stall out the engine. If revs do not fall significantly you have a vacuum leak somewhere.

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If, like above, blocking the holes does what it should then you have an IACV/IACV control problem.

KaTonyMa · Post by **KaTonyMa** » Sat Apr 18, 2015 4:56 pm

Great advice mate! Will try this tomorrow. Thanks