16v ISV Wiring

[matt33 0]

Please help! I've had obligatory rough idling on my 2l 16 valver (9A) for past couple of years. Tried 4 different garages including dealers but none of them have traced the problem. Has all the classic symptoms of ISV not working, but I've tested/changed this and it works fine. So I'm thinking it could be the signal to it that's dodgy. The black/white wire reads battery voltage, but the white wire never reads any significant voltage. Is this correct? If not, what should I do? Thanks for any help.

[flusted 0]

ditch it and run without

[Thom 1]

I have exactly the same problem, have a fully functional ISV and yet there still seems to be a fault, no error code reading, can the MFA be responsible?

[Thom 1]

Oops, I mean MAF sensor

[matt33 0]

Don't think it's the MAF as this is one of the parts I changed and its made no difference. Hoping its just a sensor/control unit or something but not sure which one or how to test?

[Jim 2]

There is also (I believe) I an ISV relay in the relay board.. apparently a bad one of those can cause bad ISV like idling problems too, so might be worth getting it checked / replaced?

[flusted 0]

theres a control box normally behind the centre console

[Thom 1]

theres a control box normally behind the centre console

 

Isn't that only on 1.8, KR engines?

[matt33 0]

According to the ETKA diagram I just looked up, the ISV control relay is only on KR's. Anyone know any different?

[flusted 0]

i expect the 9a uses the engine ecu to control it

[matt33 0]

This is what worries me, is it likely ECU is knackered? Is there a temp sensor or something I can test which feeds the ECU info for the ISV to work properly? This is bearing in mind that the white ISV wire, unlike mine, should have voltage. Still not 100% sure of the answer to that?