Foul Play Suspected

I brought my car (1991 Volvo 740 Sedan) into my mechanic because the idle was not working. He cleaned the air control valve and sensor and it works fine now. I got it back, and my speedometer has stopped working. When I say stopped, I mean it still does something! It will go to 55, then back down to 0, then fly to 30 and stay there. I called him, and he said it needs a new speedometer cluster ($200!!!) or speed sensor ($250!!!). Now, I have had this happen before, and I found it to be the wires to the speed sensor that the mechanic had disconnected and taped back together, instead of soldering and re-sheathing like he should have done. (I unhappily did that myself). Now, being a college student with a low income and a jalopy of a car, I am inclined to not repair it if I can’t find the problem on my own.



Could this be foul play on my mechanic’s part, or just coincidence that it went out right after he touched it? He is theonly person in a 150 mile radius that works on Volvo’s…

Try salvage yards for your replacement parts, it’ll probably cost 10% of these prices.

I did, and found it as cheap at $175, still a lot of money for a car only worth $500 (according to KBB)

I agree that it’s either the VSS or the cluster. Being a poor college student, you should be willing to check the VSS connection(s) and if the problem isn’t there remove the cluster, clean the ribbon wire contacts and the corresponding jack contacts (contact cleaner can be bought at Radio Shack) yourself. If not, you’ll have to either paye someone to do it or live with the problem.

Is there a you-pull-it-yourself type salvage yard near where you live? See if they have a compatible Volvo there. Much cheaper.

I know the speed sensor is in the rear of the rear axle, but would there be any reason for them to be back there or in my dash to clean the air control valve or sensor?

No, but coincidences do happen. And since there would be no reason to be near anything to do with your current symptoms it would seem prudent to first eliminate what would be typical sources of the problem.

Thanks! I am going to a friends house tomorrow (they have a garage of tools!) to jack it up and inspect the VSS and also take out the cluster and clean/inspect it.