Volvo Owners Club Forum - View Single Post - 2001 V40 1.8Gdi starting & idling issues, won't rev

theboymike · May 30th, 2019, 13:18

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I then slackened off the two TPS retaining screws so it could be rotated by hand with a little force, and set about checking the resistance values.

Basically checking pins 1&4 with the throttle pushed fully closed (screwdriver handle against the buttergly and wedged against the rubber inlet trunking), adjusting for a value of around 0.625k Ohms then wedging the TB fully open (again with the screwdriver handle) and checking the resistance value across pins 3&4. I kept doing this and adjusting the position of the TPS by tapping it with a screwdriver handle until I got similar resistance values under both conditions.

I ended up (more by luck than judgement) with a values of 0.659k Ohms both across pins 1&4 with the TB closed and across pins 3&4 with it wide open

The TPS retaining bolts were nipped up (which can sometimes change the resistance readings, although I'm not sure how close these have to be), the values re-checked and the plug refitted / inlet trunking re-attached.

Please note that if carrying out this process the pin numbers shown in the diagram above are for the female plug that attaches to the male plug on the TPS; so when looking at the pins on the TPS itself when fitted to the car they run in the reverse order - i.e. 4,3,2,1 from left to right

After this was sorted I followed this guide for re-setting the ECU, which was much quicker and easier than the previous one tried. It also had the benefit of wiping the fault codes so no more check engine light on the dash

One word of warning though; disconnecting the battery will kill your OEM radio, although that didn't bother me personally as it's never worked since I've had the car and I refuse to pay the parasites at the local dealership for the code.

I did find it hard to maintain 1200rev/min for 2 minutes as the guide prescribes since it was running very close to this anyway, however this doesn't seem to have done it any harm as it's no idling at around 900rev/min after a 6 mile drive..

It might be my imagination but the car also feels a bit smoother / less hesitant at low revs; which tbh wouldn't be surprising given the state of the old TB!

Anyway, thanks again to those who've helped (especially Alex!) and I hope this might sort others with similar issues in the future as there doesn't seem to be a lot of info around on the net.

May 30th, 2019, 13:18	#9
theboymike Junior Member Last Online: May 23rd, 2022 19:06 Join Date: Apr 2011 Location: Oxford	... I then slackened off the two TPS retaining screws so it could be rotated by hand with a little force, and set about checking the resistance values. Basically checking pins 1&4 with the throttle pushed fully closed (screwdriver handle against the buttergly and wedged against the rubber inlet trunking), adjusting for a value of around 0.625k Ohms then wedging the TB fully open (again with the screwdriver handle) and checking the resistance value across pins 3&4. I kept doing this and adjusting the position of the TPS by tapping it with a screwdriver handle until I got similar resistance values under both conditions. I ended up (more by luck than judgement) with a values of 0.659k Ohms both across pins 1&4 with the TB closed and across pins 3&4 with it wide open The TPS retaining bolts were nipped up (which can sometimes change the resistance readings, although I'm not sure how close these have to be), the values re-checked and the plug refitted / inlet trunking re-attached. Please note that if carrying out this process the pin numbers shown in the diagram above are for the female plug that attaches to the male plug on the TPS; so when looking at the pins on the TPS itself when fitted to the car they run in the reverse order - i.e. 4,3,2,1 from left to right After this was sorted I followed this guide for re-setting the ECU, which was much quicker and easier than the previous one tried. It also had the benefit of wiping the fault codes so no more check engine light on the dash One word of warning though; disconnecting the battery will kill your OEM radio, although that didn't bother me personally as it's never worked since I've had the car and I refuse to pay the parasites at the local dealership for the code. I did find it hard to maintain 1200rev/min for 2 minutes as the guide prescribes since it was running very close to this anyway, however this doesn't seem to have done it any harm as it's no idling at around 900rev/min after a 6 mile drive.. It might be my imagination but the car also feels a bit smoother / less hesitant at low revs; which tbh wouldn't be surprising given the state of the old TB! Anyway, thanks again to those who've helped (especially Alex!) and I hope this might sort others with similar issues in the future as there doesn't seem to be a lot of info around on the net.