It first started detonating about a year ago, I didnt realize what it was until about 3 monthes ago. I checked timing and it was 4degrees advanced and I had a big vacum leak from one of the lines. I fixed all that. Well its doing it again. I pulled the number 1 sparkplug and it was white(duh),checked timing, it was still good. I also did the little water cleaning thing to it last week. The fuel injectors had a good spray pattern. I'm going to put a fuel filter on it tommarow because its probably never been changed. If it still doing it I'm going to check fuel pressure. What else could it be? IAC? Damn it all to hell!!!!

 

White isn't a good sparkplug color. They should be brown.

Hot spots can cause knocking. Incredibly crappy timing could cause it.. 4 degrees advance isn't enough unless you're running something like 60 octane gas. heh. The IAC won't have much to do with it though.

How hot does your engine run?

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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

Carbon deposits, vacuum leaks, low FP, sharp metal corners in the comb chamber, knock sensor (this, no knock retard) sytem not working properly when it was before, weak/brokern springs in HEI, timing advanced too far, PROM changed and has too much advance on chip, REAL BAD GAS, old plugs, plugs too hot for engine combo, etc...

 

It is cooling fine, I already knew that white meant that it was detonating, Are there any other takers??? How can I check if the HEI is working properly also how can I find out the heat range on the plugs in it.

 

I thought white sparkies meant it was running lean. That can cause detonation too.

 

White does not necessarily mean lean, as suggested. Got some tuning to do?