john89gt

My buddy has a 92 lx and having some problems. The engine is spark knocking or poping. More of a misfire pop. The timing when he checked it, didn't change from pulling the pill out to set timing. Then reinstalling the pin back in dist. harness didn't change timing or the way the motor ran. Also he has a F303 cam with gt40 heads. He said the plug he was running strated out with 74something. That didn't sound right to me either. I couldn't remmeber what plug I have with mine. Justing looking for some help.

mattdel

Well firsts things first, you need to actually verify what the timing is at. Doing it by ear is a no-no. If you verify that the timing is indeed not changing when you pull the spout it, try hooking a jumper wire up in it's place and see what happens.

john89gt

The timing was set a 10 degrees.

mattdel

Ok. 2nd step would be to clarify whether you have spark knock, or a misfire. They're completely different things.

john89gt

I shouldn't have said spark knock. It is a misfire.

mattdel

Check the plugs out, first. Autolite 25's are the standard issue plugs for it. No platinums, no fancy **** at all.

Then check the plug wires. You can use an ohm meter to check for resistance in them, a general rule of thumb I like to use, is no more than 100 ohms per 12 inches of plug wire. Anything above that, you could start seeing problems.

john89gt

I think the plugs are different from the 25's because of the gt40's. At least mine are. I could be wrong, but I ran what plugs were in them. I dont remember the number. Could that be the problem? He has some 74@# something in them. I believe is what he told me.

mattdel

oh i forgot about the gt40's. as far as i remember, only the gt40P requires a different plug. the regular gt40's use the same one as a stock head.

john89gt

They are the GT40P heads off an explorer.

mattdel

I don't recall the plug required for those heads, someone else on here can answer that.