Hey y'all, I was wondering if you could help me out a bit. I have spark knock under accleration at about 45-50 mph and maintaining speed between 65-70 mph. I have changed the timing chain and gear, retarded the timing, and replaced the plenum and intake gaskets. Problem still isn't solved. Does anyone have anymore ideas? (And a stick of dynamite isn't an option *L*) Thanks.

Alyssa

 

You could try running slightly cooler plugs, or higher octane gas, but that's really more of a band-aid.

I'm sure someone will have something more useful to contribute.

 

Could be the deathflash. Is there a hand written sticker on the pcm saying it's been updated? A 2000 might even have it from the factory. A tuner would fix it.

 

Where is the PCM located and I'll go look for that sticker? and what's a deathflash? honestly, it sounds kind of scary...also, forgot that occasionally, it will cause my check engine light to come on (sometimes solid and sometimes blinking) and i've had it scanned and the scanner is not coming up with any codes.

 

The stock "death flash" wouldn't cause pinging/spark knock, its designed to prevent it.

How did you retard the timing? Only way to do it on these trucks is with a tuner, you can't manually adjust it like you could on the older vehicles. Turning the distributor or whatever you may have done is bad, causes issues. Undo it.

The stock computer's "death flash" (do a search) retards the timing to far as it is anyway.

After you changed the plenum, did you reset the computer (disconnect the battery, turn on the headlights for a few seconds, turn off the headlights, reconnect the battery)?

Have you checked fuel pressure at the rails? Tested the injectors? Any upgrades to your truck? How long since your last tune-up? (What plugs, wires do you use?)

 

You can retard the timing at the chain, which I'm assuming is what she did since she said she replaced the chain. I don't think that would cause an issue.

 

If the CEL has come on before, it should be stored on the computer. Have it scanned and see what comes up.

 

the colder plugs that were mentioned are Autolite 3923. they foul faster because they are colder but they are cheap if you get them at walmart. so changing the plugs every 15k won't break the bank.

try running 89 octane first. my dads 98 knocks if he runs 87 but not with 89.

and c4 is much more effective than dynamite.

 

started about a week after plugs were changed (wires havent been changed for awhile and those were whatever autozone carries). champion RC12LC4 (436) plugs were gapped before they were put in. timing was retarded at distributor (dodge dealer mechanic said i could do this, guess he was wrong *sighs*) the rails and injectors have been tested and they all came out as having no problems. the computer was reset after the plenum gasket was changed, changed the thermostat while was in there as well. no upgrades have been made except for the tranny being beefed up a bit for pulling. oil, plugs, and filters were changed about a month ago.

 

It's been scanned since the CEL has come on and nothing comes up. No error codes or anything. Tried running 91 octane, still knocks. Right now, down to considering hijacking the pcm out of a 98 that I have sitting in the yard with a bad tranny but really, really dont want to do that because im afraid it will cause even more issues.