I just completed my rebuild, and got my motor running today. I decided to set the timing(it was advanced to about 18*-20*), but ran into problems because i forgot to unplug the timing wire....DOH!!!!! As i was walking around to shut the car off, i noticed the idle change a little. I checked the timing again, and the mark had moved and was way off the scale. My closest guestimate would be that it is around 25* retarded. I cant advance it to where it should be because it adds way too much timing. It runs great, but this is very strange.

What would cause this? I checked TDC on the balancer when i put the motor together, and put timing tape on it. Everything checked out fine, but what would cause this?

 

On a fuel injected motor with a computer controlled distributor, the ECM advances and retards the timing itself. All you can do is set initial advance. Unpluging the wire keeps the computer from advancing or retarding timing, so that you can set inital timing.

 

If the motor was running at 18* advanced, and the computer automatically set back over 25* (which is what happened) the motor should not be running. But, the wierd thing is, it is running just fine. Even if the distributor jumped a tooth, it would be runing like crap. But it runs perfect!!!!!

I was told to just set it by feel/ear, then get it to a dyno.....

 

On my Sentra SE-R, I had a similar problem after the engine was rebuilt. Set timing at 17, checked later it was 25 or something, set back to 17, checked later and it was 13. It turned out the throttle position sensor was the culprit. The car ran great initially but went wayyyy down on power as soon as it built any heat. After a new TPS was swapped in, the timing problems went away. I know F Bodies and r!ce burners are totally different animals, but you never know.

 

Anybody?

 

Don't even try and check the timing with the ESC plugged in.

Unplug it, set the base timing, then plug it back in.

If that doesn't feel right unplug it, adjust the base timing, then plug it back in.

That's the only sure fire way of finding the timing for your rebuild if you've done mods, other then a new chip.

 

Even by unplugging it, i cannot get the timing mark to where it needs to be. If i advance the timing that far, the motor wont even run. I just dont understand what would have to happen for the mark to have moved. Its almost like thetiming gear spun on the crank, or the balancer did.....


Its strange.

 

Only thing I would think happened is that the balancer slipped. If you didn't buy a new one, you better check that.

 

nice car man.. any idea on how much it weighs? guess ya havnt ran it yet.. what kinda times are ya expectin?

 

The balancer is new.

Thanks for the compliment.

I have had the car running for over a year now. I just swapped to the TPI setup a few months ago and ran 13.60 on the stock chip running pig rich. I realized right after i got the custom chip burned that i had piston sealing problems on a motor that had less than 10,000 miles on it. I just finished my rebuild, and I am still in the break in stage with the motor, and i have the timing set by ear. It seems to run alot stronger, but i havent gotten on it yet to really tell. The car is a daily driver, and I am going to baby it for a few hundred miles.

Oh and the weight is gonna be somewhere around 2900-3000 lbs.