240 volvo speedometer

drmike · Post by **drmike** » 21 Dec 2008, 09:57

93 240 speedometer won"t go above 32 mph. suggestions?
who can fix this?
also what is the oil plug thread size for this car?
thanks,
drmike

Post by **MadeInJapan** » 21 Dec 2008, 11:47

Not sure about your last question but I had the same problem with my 240 when I got it...I took the plug out at the rear differential, cleaned the contacts really good and plugged it back in and things were restored- you might try that. If that doesn't get it, it could actually be the probe that goes into the rear differential that needs to be shimmed. I don't know much about doing this but I'm sure that Bill or others will know and can describe the process to you.

Post by **billofdurham** » 22 Dec 2008, 11:41

it could actually be the probe that goes into the rear differential that needs to be shimmed.

I have never heard of the sensor needing to be shimmed as it is set at the correct distance to read the pulses in the diff. The only thing I can think of for the setting to change is if the securing ring has worked loose and the sensor has moved away from its proper position.

Certainly there have been many failures due to bad connections at the plug on the diff housing and some where the sensor itself was contaminated. Remove the sensor and carefully check and clean the connectors. Also, as far as possible check the wiring from the sensor to the speedo for cuts or breaks. A final thing to check is the earth (ground) leads under the dash and in the right footwell.

I don't know the size of the oil plug thread and can't find it in any of my books. Usually I go out and ask for a new plug. The seller usually knows which one it is.

Bill.