My Rev 2 turbo doesn't know how to idle

[danjama]

Well, kind of. I can leave it sitting on idle happily. But if I come off throttle or dip the clutch the idle will sometimes dip to 500 or lower. Then if i just tap the throttle to bring the revs back up it will hold idle perfect again. It's just a bit all over the place and it's starting to bug me! Sometimes when dipping the clutch it will stick around 1000rpm instead of going to 750rpm. I changed my ecu temp sensor as I had a cold idle issue which really improved it, but it's still doing it sometimes.

I have a feeling someone messed around with the TPS or something to sort the idle when it had the cold idle issue, but I have no idea how to check the TPS/throttle body/AFM are all set correctly, even after lots of reading on the subject.

What do people think? I'd love it if someone in Essex or nearby who knew their xxxx could look at it for me.

https://www.youtube.com/watch?v=lJ7erqBd7Xo

[Driftlimits Performance]

The iscv will open when the Tb is 0.5mm from closed for a little overlap to avoid the symptoms you have. Remove and clean the iscv check (they never break) then set throttle with feeler gauge and multimeter. they should be serviced periodically and often not.

[Pauln]

As above best to take the throttle body off and give it and the ICVS a good clean. Don't forget to order new throttle body and ICVS gaskets from MR T.

It may also be worth taking the cover off your ECU to check for leaking capacitors as I believe one of the two I found leaking in my Rev 2 ECU was in the area that controls the ICVS and any damage to adjacent tracks could be a contributing factor.

Having had similar issues and done all the above, I now at least have a stable idle speed, all be it higher than I would like.

Paul

[danjama]

Thank you both. I cleaned up my iacv a while back when trying to suss my cold idle issue, it looked good and moved freely. So I will try to figure out setting the tps and also check the ECU condition. This is behind the boot carpet is that right?

[Pauln]

Yes, the ECU is behind the carpet on the left hand side of the boot.

To setup the TPS:
1. Check that when the throttle is closed there is no gap between the control arm and the throttle stop screw.
2. Unclip the connector from the TPS.
3. Connect a multimeter to the bottom two pins on the TPS (pins IDL and E2), and set the meter to read ohms.
4. Check your meter is showing a resistance, ie there's a connection between those two pins on the TPS.
5. Insert a 0.60 mm feeler gauge between the throttle stop screw and the throttle "control" arm.
6. Loosen (but do not remove) the two screws on the TPS, and then slowly rotate the TPS until your meter shows an "open" circuit, ie. there is no connection between the two pins - you are trying to find the exact point when the "switch" opens so it's worth moving this back and fro a few times to establish the correct point.
7. Tighten the two screws on the TPS
8. Now check whether the TPS is set correctly by first inserting a 0.50 mm feeler gauge between the throttle stop screw and the throttle control arm. Your meter should now show a resistance between the two pins ie. the switch is closed.
9. Finally insert a 0.70 mm feeler gauge. Your meter should now show an "open circuit", ie no connection between the 2 pins.

Tip
I've made up a simple adapter for attaching a multimeter to various connectors on the car. All you need are a couple of the really small spade connectors sold by Halfords attached to two lengths of suitable cable. With the other end of the cables screwed into a bit of terminal block. The small spade connectors will fit over the pins on the TPS and the MAF and the probes of the multimeter can be screwed down in the terminal block. Saves a lot of faffing around.

Paul

[danjama]

Thanks for that Paul, nice detailed post and top tip, hopefully this will sort it