I recently acquired a 1987 Z28, 305 4BL. In 4000 miles I have had to do very little to it, ie. water pump, a belt, and some vacuum tubing.

This morning the ignition module went out, evidentally to a shorted out spark plug wire. I had the module tested, replaced it, and was replacing the plug wires one at a time to be sure I put them back correctly. I noticed that the order appeared to be odd. I wired it up, started it, and everything is fine now.

However, the firing order is NOT the chevy standard 1-8-4-3-6-5-7-2. It is 1-7-2-5-8-4-3-6. When I use the chevy standard order, it just spins and backfires, so I just shrugged and put it back the way it was.

Should I be concerned, or just leave well enough alone?

 

You're not counting the cylinders right. You're using the F*rd method.

GM is odd #s 1357 on the driver's side, even #s 2468 on the pass side.

 

Nope. I double checked that as well. Overall I spent more time rechecking the count, routing, and order than I did anything else.

Wait. Just looking at my notes, I may see an issue. With the exception of the 1st and 5th cylanders, the order is reversed. I read the distributor clockwise. Is this correct? If not the my 1 and 5 are simply switched, however this is how it came off.

 

VOILA!!!

1 and 5 plug wires were switched on the distributor. This threw my count off. I was trusting that since it already ran, it must be right. There's a HUGE difference in horsepower now that the wires are right.

Thanks for everything, and I apologize for my newbieness.

 

i'm not exactily a newbie and i mess up the firing order every time, sort of. when i was in high school i learned it backwards 12756348. it's not really a problem for me but i always mess up trying to tell soemone else how it is or works. i know it goes clock wise on the rotor but if i don't stop and think i confuse myself.

 

What happened was I just put the wires back on the way they came off. I knew what the firing order should be, but since it had been running fine enough, I didn't bother checking the previous owners stuff. I put the last one on, and realized it wasn't beside the first. LOL

The car ran only so-so before. I own an '81 Berlinetta with a V-6 and factory 3 speed manual, that is in bad need of an engine rebuild, and it made the '87 eat dust. They're a little closer now. Makes me think that maybe those two wires were why I got the car so cheap!!!!

 

lol..ede the dyslexic (sp) tuneup guy