Questions and Answers

Popping Toyota Corolla Q. 1987 Toyota Corolla KE-70 Wagon, 4 cylinders, manual transmission. After "tuning" up the car the car ran worse. It seemed to loose power and also this constant backfiring popping noise from the muffler when you are driving and you take your foot off the accelerator.

The oil, filters, condenser, points and plugs, were changed.

A. You must have a non-USA model. Toyota did not use points in USA models in 1987. If this is indeed the case, I can only answer in general terms.

If you did not have this problem before the tune-up and it did surface afterwards, then it's safe to assume something with the tune-up caused the problem. From what was changed in the tune-up I would say the points were not adjusted properly.

The points spec is often given in how much gap there should be. That is to say how far they open at the widest point. I have found that while this is basically okay, I always adjust points by the dwell angle. To do this you will need a dwell meter.

The way I adjust the dwell on a car is first I remove all the spark plugs, remove the cap and rotor and ground the coil wire. Then I loosen the points mounting screws just enough to move them with the tip of a screwdriver. Hook up a remote starter and turn the ignition key ON. Crank the engine and adjust the points so you have a dwell reading of 50 degrees. Check the dwell spec to be sure this is correct for your engine. Most of the four bangers I've seen get set to 50 degrees.

After you get to 50 degrees, lock down the points and recheck it to be sure they didn't move. Now, importantly, apply a small amount of grease to the distributor lobes. You should get some with the new points. If you don't do this, the block that rides on the lobes will wear out and the gap will close.

I think this will take care of your problem.

Additional Information provided courtesy of ALLDATA