I am in need of some expert advice for my '92 740 B230F. I was playing around with the TPS today. Is it 'normal' for the car to idle and rev just fine with the TPS unplugged on a hot engine? Starting the engine with the TPS unplugged when cold will cause the engine to stall within a few seconds. The sensor is adjusted so that it 'clicks' as soon as the throttle moves. I am asking because I'm trying to diagnose a rough idle on start issue and am going though the list of possibilities. Any suggestions would be greatly appreciated.

JTK

 

What you describe seems normal to me. I always equated the TPS as analogous in some respects, to a carb's choke circuit. Is your rough idle on hot starts, cold starts? Sometimes covering all the basics first eliminates some of these annoying habits our aging cars develop. Have you removed the TB, cleaned it thoroughly and renewed the gasket if necessary? Plugs, cap, rotor, wires? Any codes?

 

Use this as a guide Engine: Fuel Injection Body and Throttle Position Switch Adjustment

 

Thank you for the advice on the TPS. I cleaned it out two years ago and it really needed it. I checked it again last year and looked great, put in a new gasket while I was at it. Plugs, cap, rotor and wires are new within the last six months. Strangely, no engine codes. I actually have a separate thread going on the rough idle if you are interested in reading up on it.

https://volvoforums.com/forum/volvo-...problem-60094/

I'm going to be replacing some coolant hoses next weekend and hopefully can get some work done on the intake system while I'm at it.

Thanks again for the reply, I am always open to advice.

JTK