C20LET Idleing High

[krobinson]

My C20LET Nova is idleing at 2k revs, its strange in that it's almost like the engine thinks 2k is actually 1k. When rev'd it drops back to 2k perfectly.

I've replaced the Throttle Position Sensor, and also cleaned out my ICV with carb cleaner until it was shiney clean and freely moving.

The ECU light stays on, and when I earth the diagnostic plug it reads out:
21 and 22

Which i'm aware is:

21 Throttle position sensor - High voltage
22 Throttle position sensor - Low voltage

It also read out either 17 or 71 as a fault code which is either:

17 Knock sensor 2 -No change in voltage
or
71 Air Temperature Sensor (ATS) High voltage

Anyone know what could be wrong and how to fix it?

Keith

[The Simps]

did you spray all ur inlet including the throttle bit?

after I sprayed mine my revs stuck until I wd40'd and worked it. worth a try?

p.s. Its probably 17 not 71 cos iirc 17 always comes up cos engine isn't cranking so won't detect anything

[krobinson]

I did the test whilst the engine was running.

My inlet was blasted clean and has no spray on it, its bare.

Not sure what else to try

[The Simps]

different ecu just to rule it out?
coolant temp sensor? that can effect idle.

[Clean 2.0 nova]

Could be a stupid answer but have you tried making sure the accelerator cable is not taught or is there a idle setting screw?

[krobinson]

Its a new sensor, and the dash rise's as the engine warms up, but might still be worth looking at? Its a non-genuine sensor.

[krobinson]

Could be a stupid answer but have you tried making sure the accelerator cable is not taught or is there a idle setting screw?

My cable is actually too long, so wont be that, and I dont think there is an idleing screw on the TB.

Keith

[The Simps]

Its a new sensor, and the dash rise's as the engine warms up, but might still be worth looking at? Its a non-genuine sensor.

The blue spade terminal feeds the dash display whereas the CTS tells the ECU whats happening. Worth just trying another one if you or a mate has one lying around? If its sending wrong signals ECU might think its still really cold hence over revving (choke effect).

[krobinson]

I've clamped the ICV pipe and the idle's droped perfectly, so it must be the ICV, going to price a new one tomorrow.

How do I clear the fault codes now to see if they re-appear?

[The Simps]

disconnect the battery for say an hour to be sure.