LS1 Manual - Revs picking up.

[BookMe]

I'm sure this has probably been done before, but I'm not sure exactly what to search for.

I'm having a problem with my VY calais LS1 Manual (VZ 6 speed).

Whenever I take it out of gear after moving, the revs pick up to 1500rpm. Then when I come to a complete stop, they drop to idle ~800rpm.

Eg. Slowing down using the gears, revs drop to 1000rpm, I push in the clutch and then the revs pick up to 1500rpm, till I stop.
or
Travelling along in any gear, push clutch in, revs will either go up or go down to 1500rpm and sit on it till I stop.


So far I've had a computer hooked up and the TPS is registering that it goes to 0, whilst it revs at 1500rpm. Could not find any faults at all using the computer.
The throttle body blade is not sticking.
I have completely changed the PCV hose.
I have done a PCM reset and it's made no difference.

Haven't checked the IAC, but thinking I might give it a clean?
Going to pull out the TPS at the same time just in case.
Will give these two a go then try reseting the PCM again.

Any other ideas?
Thanks.

 

[TigaVTSS57]

Had the same thing with my car. On one of the ls1 forums in the states, they said to remove throttle position sensor connector, iac connector and turn ignition on,(not turn motor over) for 30 seconds, turn off, reconnect and start car. Havent tried it myself but sounds like its worth a try.

 

[BookMe]

Will give it a go this afternoon. I heard that after turning the car to accessories with everything unplugged, you should hear a chime after 10 or so seconds.

Will let you know how I go.
Thanks.

 

[BookMe]

Pulled out the IAC Valve and cleaned it with WD40. Disconnected the TPS, then turned the car's accessories on. Check engine came on. Plugged everything back in and started the car.

First thing I noticed was the cars fuel consumption whilst idling. It dropped 1L/h (hour)
Was absolutely perfect when I drove away. Drove for 10 minutes.

Got petrol, then drove away and straight away it was back to normal, but maybe even worse. It went to 2000rpm for a while.

Maybe the IAC valve is no good?

 

[TigaVTSS57]

Might have to get a tuner to take look at it.

 

[BookMe]

Going to reset the PCM on the weekend.

Found a couple threads from some yanks having the same problem.

Will post up what I do.

Thanks.

 

[BookMe]

I believe the tune was done by Castle Hill Performance and it's probably been locked.

My mechanic mate has been speaking to two tuner friends of ours and is going to try to sort something out with them.

So if it is locked then I will need to buy a new computer.

Tried spraying brake cleaner over everything this afternoon and it didn't show any signs of a vacuum leak.


Also this afternoon after the revs went to 1500rpm they didn't drop when I came to a stop at my mechanics. It only stopped when he touched the throttle body, BUT I had been touching it before him.

LS1 Manual revs pick up - youtube

Anyways a look at the tune or retune is probably in the near future.

 

[BookMe]

Just reset the PCM.

Drove away and at the first gear change/ putting it in neutral, the revs went to 1500.

I guess the only thing left to do now is to get the computer retuned.