Throttle position sensor adjustment

Spazola · Post by **Spazola** » 31 Oct 2011, 16:07

Ok last question today. I did try to find the answer on you tube. How do you adjust the Throttle position sensor

Post by **billofdurham** » 31 Oct 2011, 17:30

: TPS adjustment.jpg (14.44 KiB) Viewed 9785 times

Bill.

Post by **JimBee** » 31 Oct 2011, 21:18

I though I understood what the TPS is, though still confused about what it does. But now I'm confused again. In my '96 850, that little black module on the side of the throttle body, that receives the butterfly shaft when it turns, doesn't have slotted screw holes. The tiny 7? mm screws just fit tightly. Am I mis-identifying the TPS?
A picture would help.

Post by **jimmy57** » 31 Oct 2011, 23:00

On all but a few 90-93 240 manuals, the item on throttle is a two switch unit. A throttle closed switch that clicks and a wide open throttle switch that makes little or no noise when it closes.
All 850 fuel systems use a TPS which is a resistor track with a wiper brush. TPS is usually a no adjust affair with screw holes that are not slotted. The throttle switch assy. has slotted holes as it requires precision adjustment.
When adjusting it and listening for the click, do not adjust to a "hair trigger" adjustment. The later prescribed method from Volvo has you use feeler gauges so the adjustment is not done wrong. The risk is that if it takes an almost imperceptible movement of throttle to make it click then it may not make contact and signal closed throttle on cold mornings and engine can flood as a result. If the switch doesn't indicate closed throttle the idle air control valve will go to a fixed range with low air flow and the fuel injected for cold start will too much for that little air and it will flood.