Still idling too high
 

Right i still have the issue of the car idling high, currently it's at 1400rpm which has dropped slightly since work.

This started when i replaced the TB with a replacement 2wd and changed the throttle bracket to an Airtec item as prior to that it was all idling fine.

I have removed the inlet and fitted new plenum gasket, helicoiled the threads in the plenum so it perfectly tightens up and fitted a new O ring between the throttle body to replace the old cometic item.

The TPS was set at 0.35v at idle before the TB was removed so will still be in the same place now fitted back on..

I have the idle screw pretty much all the way in but i seem to remember that it was half way when fitted to the car once before, so what is causing this?

How to test the ISCV?

Any idea's folks?

Best to borrow one (ISCV) and try, i've had to change one once, as the car started idling high.
Don't know how to test them though or if you can?

does the idle drop iff you unplug the iscv?

Are you sure it doesnt have a air leak? might be worth asking a local garage if they have a "smoke probe" to put into the intake system

Completely cuts out, still runs the same if the TPS is disconnected

Can anyone comment on the idle screw position, as.I would have thought they would be roughly similar as I said above I could have swarn it was half way in before when the car was setup and running spot on

Try winding the idle screw out a little at a time bud as the car should idle with the valve unplugged.
Make sure the car is up to temp as will not idle with the valve unplugged when cold

I've just done that now Gav, plugged the ISCV in and the revs started to climb so quickly disconnected.

So is it looking to be an issue with the iscv?

try the TPS at 0.20 - 0.28 and test again,if you have the pf09!!

Get it warmed up, unplug the ISCV and set the idle to 1000 rpm using the idle screw. The engine should idle fine with the ISCV unplugged. If you can't get it screwed down that low, then there's something wrong. IIRC the TPS will affect the ISCV and therefore the idle speed.

Firstly do you have 2WD management, i.e. L1/L6, by your TPS reading I am guessing you don't and therefore have L8?

Get it up to temperature and disconnect the valve, make sure no electrical load is applied and the fans are not running!

Then UNSCREW the idle screw to increase the idle speed (You will need to loosen a locknut first) it's important this is tightened correctly afterwards, else it and the idle screw can fall out!

You want to see around 850 RPM, reconnect the valve, the revs should raise then fall again.

It sounds like at the moment you are using the ISCV to control the idle speed :cry:

Martin

I will have to wait to get a reading as i don't have a multimeter here

Martin it is L8 - i have the idle speed set at temp but when i refit the iscv plug the same applies it revs up to 2000rpm and thats it

Oh so at least the base idle is set correctly now, I imagine the valve is TPS related, incidentally with L8, unplugging the TPS will not have the same effect as it does on 2WD, actually it will probably make it run worse.

Martin

ok Brammer,check the TPS again with multimeter,and check for air leak in your plenum!

The fact it's runs ok without the valve connected shows there not to be an air leak, clearly the ISCV is being told to open.

Martin

i don't have test this case,but before he fit the new plenum the car run perfect..strange! he must check all these

PS,i have the same problem with my hart plenum and i re fitted the original gasket again!

The car ran fine on the plenum originally, but the threads on the Hart are weak and some where stripped so it had to come off to be helicoiled - every hole was done and new gasket and O ring used - i have removed the iscv and stripped it and will soak in petrol for a few hours as it's not 100% bad at all - i do hear you regarding the tps i will check that Monday when i have access to the meter - currently set at 0.35v CT and i beleive i could only get 3.09v WOT due to the Airtec bracket but again that needs to be checked again.

I have set this before at this figure and it ran perfect but their are so many alternative figures out their i think it's trial and error.

One thing the car runs well i just want this sorting

Cheers for the advice lads it's much appreciated :DD:

I have had the same problem and indeed this was the solution.! Dont adjust the TPS above 0.3V!

I'll try it under 0.3v then and see if it makes the difference