I have trouble running the stock timing at 6*. Right now my car is running at 2* and if I do set it at 6* (esc wire un-hooked to set properly) the engine makes noise under a load. Sounds more like pinging and rattling. The car has a fair amount of mods and just finished porting the plenum heavely. I just purchased a G-Tech and am trying to get the best runs but I can't play with timing to much. If I do set it advanced, the car always makes the same noise. I always have to back it off and I do use 92+ octane. Any advise were to look on this.

 

Check the balancer vs TDC.

 

TDC being #1 cylinder in dist. cap right? Is it possible that balancer could be off. Have seen this on Fords but not really GMs'.

 

Is it the stock damper? ("Balancer" is not the proper name for that piece.)

 

yeah, I am almost positive it is. I can't figure out what the problem can be.

 

My "damper" slipped some years ago on my 86 TA with about 130k miles on it. It was off about 20 degrees.

 

If it makes you feel better, my engine is set at 2deg. Apparently it didn't like anything higher. 4 was okay but still a little tough on hot starts.
My damper hasn't slipped.

 

Is thisa normal problem or should I continue to look into this. The car seems to perform very well and has gobbs of torque at low end. I just want to make sure that I shouldn't be looking into and engine issue or anything.

 

Well "fair amount of mods" is pretty broad. 2 degrees is what your engine may like now.
I run 93 octane, 2 degrees advance, "a fair amount of mods" and I have no pinging. The car runs like a raped ape too. It's just what my engine wants. It doesn't always want what the book says.

 

Are you running a non-stock PROM like your sig says? If so, it could be that the timing curve is more aggressive than stock or the knock sensor has been desensitized. If you still have the stock PROM, reinstall it and move the timing back to 6 degs and see how it responds.

 

I didn't think of that. The aftermarket prom is in the car and yes I remember when I had it made that the knock sensor was to be de-sensitized. They told me to run my car at stock timing settings and go from there. If I have to back the timing off to keep it from pinging than that kind of defeats the purpose now doesn't it? Any suggestions from here. Should I pull the prom or leave it? I haven't gotten any track times yet and maybe should leave it to see what I run first with and without. BTW, what good is de-sensitizing the knock sensor anyway? If it isn't and it retards the timing, you loose power. If it is de-sensitized, than you risk pinging in the engine. True??!

 

My buddy at work had a prom in his and he had problems with the car running where he knew it should. Pulled the prom and put the stock one back in the car ran quicker in the 1/4 mile.

 

De-sensitizing or disabling the knock sensor makes sense when you're picking up false knock, say from the valvetrain. In my limited experience the knock sensor does a pretty good job identifying knock on a lightly modded engine. With the stock settings it pulls timing even before knock becomes audible. If you're getting audible knock with the sensor hooked up then sensor settings in the PROM really have been tweaked.

I picked up some HP based on quarter mile MPH when I disabled the knock sensor through the PROM, but I made sure that the timing curve in the PROM was conservative enough that it didn't cause much knock at all, certainly none that you could hear.

If you can, run your car with both PROMs at the strip with distributor set so that you don't get any audible knock. Don't be afraid to set initial timing back to 2 degs with the aftermarkret PROM if that's what it takes to get rid of the knock. The total commanded timing (initial + PROM) may still be higher than stock based on the timing curve in the PROM. See which one gives the best MPH. That's the one that's making more power.

 

Yes, do this first. Beond that you gotta know what you computer is doing with the timing. Sounds really low to me. I ran 13' with the stock chip and 6-10' with an aftermarket chip. Still, the total is 34-38 depending on where I set the initial.

As far as determining TDC you can make a piston stop out of an old spark plug. Drill the electrode end and press or braze an extention which will protrude into the cylinder enough to touch the piston slightly before it reaches TDC. Remove all the spark plugs and install the special plug in the #1 cylinder hole. CAREFULLY rotate the engine by hand until the piston touches the stop. Mark the balancer where it lines up with zero on your timing tab. Then, rotate the engine the other direction until the piston once again touches the stop. Again mark the balancer. TDC will be halfway between the two test marks. Mark your balancer there. This new mark should be pretty darn close to true TDC. Then you can reinstall the spark plugs and recheck your timing. I would bet your initial is more advanced than 2' unless it's all built into the chip.

 

I think what I will do is pull the performance prom and run the car with the stocker in it. I will set the timing at 6* like it says and run it at WOT and see if I can hear anything. That right there will be enough to know if it's the prom or not. No way to set it at 6* with performance prom in car! To much noise. If the noise is gone, than I will know and then will play with it at the track for official testing. Thanks for all the help!! Remember: if there are no black marks, you didn't have fun!!

 

I want to thank everyone that helped and gave me ideas on this. I pulled the performance prom and put the stocker back in it. I then set the timing at 6* like it should be and went for a drive. I got on a nice straight away and hit it off the line. Performance was awesome and it even seemed to pull better at full throttle and there was NO KNOCK!!! I even buried it at 30mph and it down-shifted, spun the tires, and took off again with no noise. I will definately run this at the track next spring with both proms to see which will net me my better 1/4 mile time. Thanks again!!