My mother's car, a 1991 Civic Wagon, is pinging. I took out the Bosch Platinum plugs and put in NGKs, no difference. I fed it about a gallon of water through a vacuum line and made lots of steam, still no difference. I checked the timing and it was retarded according to the light, but the distributor is fully advanced. So I checked the cam timing (it was correct) and changed the belt, which was loose. No change yet. I have backed off the distributor to stop the pinging, but I would like to have the timing where is should be. Two things possibly related: a crank angle sensor and 02 sensor code (have not come back since I reset the ECU). And at WOT it doesn't usually go past 6000 rpm (redline 6500), it just slows down and stays at 6k (smoothly, no bucking, sputtering, etc.) unless I back off the throttle a little.

Any ideas? Can timing lights be wrong? Am I missing something?

 

Are the injectors clean?

Also, what shape are the plug wires in? If they have any hardspots in the insulation the resistance of the wires could be screwed up.

 

The wires seem ok, I guess checking the resistance wouldn't hurt. I'm not sure about the injectors. What's the easiest/cheapest way to clean them? Still wouldn't explain the fact that I can't get the timing right, it won't go far enough to hit the red mark on the pulley.

 

My thinking is that if it's running too lean it will detonate, and that limits your timing.

Just pull out the injectors and soak them in carb cleaner.

 

OK, I'll try that.

 

I probably should of taken the o-rings off of the injectors. They swelled up in the carb cleaner and I ripped one of them trying to get an injector back in.

 

lol, oh yeah 1stGen's after-the-fact warning: Spraying rubber items with carb cleaner is OK, soaking them causes them to swell to 10000 times their original size and 1/100th of their density/strength.

 

I got some o-rings at a hardware store that seem to seal it for now until I get the right ones. The timing didn't change. I might just give up, since it runs good where I have the distributor now (probably about 5 degrees retarted from the red mark).

 

Have you been checking the timing with and without vaccuum advance? Kinda sounds like the lines are reversed.

 

There is no vacuum advance, it's all electronic. And I have been putting a jumper across the "ignition timing adjusting connector."