Hey all, ive got this really anoying problem with a 740t volvo. The problem i am having is it is idling at 2k instead of 750.
the car also have a gas conversion so its runs on Petrol and Gas. On petrol it runs rich, idles high and blows black smoke and also revs its self, eg like some one is pushing the Accelerator then letting go then pushing it again. On gas it just idles high. Ive checked the air flow meter and thats working. TPS is working.
This all started after i rewired the engine bay because of the wires degrading and shorting its self out and wouldnt work on Petrol.
ive tested the new wires for Shorts but found none.
checked all the wires to make sure they go to the right sensors/plugs and they are all correct.
Checked the sensors and they are all working.

I found out if i Put a clamp on the Pipe from the Throttle Body to the Air Control Valve it idles at 750.
ive checked the ACV it works, cleaned it and put it back and still didnt fix the problem.

Any help would be great
Thanks
Ph33R

 

Facinating , I've never even heard of a flexible fuel Volvo turbo. I would be very interested in finding out how the ECU could differentiate between using propane? or petrol. Different ECU's? If the problem started after the wiring work, the problem must be in the wiring somewhere. They can be very aggravating to run down. Bad ground maybe?