High Idle.........

Rory

Rory

Lifer
After a weekend of sprinting(2 weeks ago), the car has managed to give itself a 2000 rpm idle hot or cold.

Ive been through all vac hoses, all ok.
Changed the map sensor, no change
Changed the Coolant temp sensor for a known working one, no change
Whipped the inlet manifold off to check the inlet itself and gasket, all ok.
Diagnostics showed the CTS.. No way i have 2 duff Sensors???
Changed the ICV for a known working one, no change.****

The same weekend, the alternator belt started giving up, but i cant see how this would cause the problem

This is driving me nuts.

As always any help is much appreciated.

Rory
 
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J

jayc-glanza17

Fresh Recruit
i had a similar problem still got it, but it got better with idle screw.
but mine had somehow vibrated itself loose after few track seesions.

other then that not sure matey.
 
Rory

Rory

Lifer
Keiran - Disconnected the cable, still the same.

madman (John??) - Changed over for a known working one, my own one was done not to long ago.

jayc - As what Murray said.

Racking my brain this one.
 
Rory

Rory

Lifer
Never thought of that Terry? Ill take a look tomorow (time permitting)
Im presuming it just screws back in, ive never had a look at one to be honest.
 
Texx

Texx

Super Moderator
You can't really get to it without unbolting the housing from the bottom of the throttle body. Pull the inlet pipe off the TB and with the engine running block the inlet port to the wax stat off using your finger. If the idle speed drops right off then it could be worth investigating a little further. Though TBH, I'd doubt the stat would cause the engine to idle so high, but still it's something worth checking.
 
G

Gtstu

Member +
i have the same problem on one if my gt's iv tried all of the above and also tried a different inlet manifold a tested TB, ive removed the head replaced all gaskets etc but still no joy
 
Rory

Rory

Lifer
Terry - Ill take a look at the wax stat, throttle body will come off in a couple of minutes anyway.

Skalabala - No shaft play.

Stu - Thats a bit shit buddy, im hoping to find out asap!
 
Rory

Rory

Lifer
Changed the T/B for one i know works, changed a little bit but not much.

Think ill try a new Coolant sensor and go from there. Will possibly presurise the system and see if it pops out any leaks
 
wildchild

wildchild

Member +
try swapping the TPS. Else the next step is to check on the injectors.

Its either sucking air from somewhere or an overflow of fuel.
maybe the inlet is cracked?? :-0
 
weeJohn

weeJohn

Lifer
Pull the plug off the tps and link out the bottom 2 connections on the plug. That will make the ecu think its closed and rule out the tps, if there is a leak as well it will let it rev to about 1600 rpm and then cut the revs if its leaking air in somewhere else.

I know you said you checked all the vac pipes Rory, but if the belt was going is it possible it damaged the power steering pipes that run down the back? Easy to check, pull the pipe after the throttle off and stick you finger over the hole.
 
Rory

Rory

Lifer
TPS is working as it should, pull the plug off and it revs even higher. Plug it back in and it pulls it down. Doesnt mean ill not try bridging the pins though. Need to rule everything out at this stage! :haha:

Ive yet to test the injector o-rings. If there were a dodgy injector that was sticky would this cause the higher idle? The car runs fine with no stutters etc. Reason i ask is the fact the fuel pressure drops off instantly after shutdown, possibly related??

Only thing that puzzles me is the fact it got progresivly worse over the day of the sprint! Aye the idle problem!

John - I dont run the vac lines from the rack, they have been blocked off.
 
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