Could this be the cause of my Jeeps detonation problem?

[243]

My Wag started pinging at light throttle again. I noticed it on the way home from work today, if I floored it, the pinging seemed to go away.

Could the counterweights be sticking in the open (advanced) position so that light throttle (vacuum advance) causes to much advance?

243

[JW]

My 90 GW used to do something similar to that. The timing was way to advanced (17, which is where the sticker under the hood wanted it for smog reasons) so I backed it down and it went away. Good luck.

[reddog]

Not likely that they are sticking but possible. More likely that you have too much advance as JW suggests. In the distributor carefully pull the roll pin that holds the trigger then you can unscrew the plate with the magnetic pickup on it and check the mechanical advance weights and springs. You want the mech. advance to come in pretty quick. You may have an adjustable vacuum advance diaphram. A small hex wrench is used to adjust it. First check your timing.

Kerry

[Veepster]

hey 243.it may fit in with the other post regarding pinging at rejetting the carb.........when you floor it the power valve opens and allows more fuel into engine whick would alleviate pinging if it was lean induced

[243]

I retarded the timing from 15+/- to 12+/- and have not had a chance to mess with the Edelbrock. I'm sure it won't hurt to jet the carb a little richer, Edelbrock states that the 1400 series carb is jetted for economy. It seem to be an intermittent problem which raised my concern about the weights.

243

[Veepster]

it could just be on the ragged edge of lean and it only shows up when the environmental conditions are at their best...which will make the vehicle run even leaner......

[243]

Yep, environmental conditions...mini-heat wave in Houston, probably 85-90 degrees today.

243