Jim Grant's Tech Tips

'92 Mazda MPV, Poor Gas Mileage Timing Belt Related?

Q: My ’92 Mazda MPV van is consuming a lot of gas and has poor gas mileage after the timing belt was replaced at the garage. What would be wrong? Please note that my van had to be towed to the garage because the belt was broken,

A: I would suggest having the timing belt checked to be sure that the valve timing is correct. Your vehicle, like many others, can start and seem to run just fine with the timing belt off by just a tooth. The problem is performance will be off and gas mileage will drop. You should also be sure that the bushing in the timing belt tensioner pulley is okay. ALLDATA Information Systems shows Mazda Technical Service Bulletin # 01-001-00R that addresses a problem of stalling and/or lack of power after timing belt replacement caused by a worn tensioner pulley bushing. The worn bushing can allow the timing belt to jump or tear resulting in incorrect valve timing. A recheck of the work performed may provide the answer to your poor gas mileage.