95 Chevy 383 Timing

[eg30.06]

I have a 95 k1500 with a HT383. Has 1 6 rockers and adaptor plate to a bored tbi. Trying to figure out what to set my base timing to. I have a hesitation when revving it up and has a bad ping with low throttle and heavy load. I got a chip from tbichips but he is unable to give me a for sure answer weather to set my base timing to 0 or advanced. Currently I have it set at 10 degrees advanced. Reason for that is years ago when I bought the chip it came with instructions that I think said to set base timing to 10 or 12 degrees.

 

[Schurkey]

You complain about "bad ping" but you set the timing 10 degrees advanced?

 

[eg30.06]

Yes I believe its spark knock. Goes away if I drop a gear and give it throttle.

 

[evilunclegrimace]

A As a rule of thumb, increased cylinder pressure increases mixture density. With higher density comes a quicker flame rate, thereby raising effective cylinder pressure and requiring less ignition timing. A rough relationship between a compression-ratio change and a spark-timing change suggests 1 degree of retard for every point of compression. Keep in mind that several companion variables, such as chamber design, mixture motion, and fuel quality, will also affect the flame rate and pressure. Suggestions? Load your truck with a burden typical of what you'll be towing and adjust the initial spark timing to threshold detonation under WOT acceleration from about 1,500 rpm. This technique should also compensate for fuel quality, underhood air temperature, and net cylinder pressure.

 

[Schurkey]

In other words, back off the timing until the ping goes away.

 

[eg30.06]

So this morning I backed off the timing until the pinging went away plus an additional 2 degrees. Now while I baby the throttle It stumbles some then smooths out. Also if I go to rev it up it also stumbles then revs. Any ideas? To much fuel?

 

[Schurkey]

Where did the timing end up? Zero? Four advanced? Six retarded?

Have you connected a scan tool to look at the data stream? I'd want to know why the knock sensor doesn't seem to work. I'd be looking at short- and long-term fuel trim, MAP and throttle position sensors. Any other sensor that seemed "odd".

Who knows? Maybe you've got stored codes. Sometimes codes are useful.

 

[eg30.06]

Where did the timing end up? Zero? Four advanced? Six retarded?

Have you connected a scan tool to look at the data stream? I'd want to know why the knock sensor doesn't seem to work. I'd be looking at short- and long-term fuel trim, MAP and throttle position sensors. Any other sensor that seemed "odd".

Who knows? Maybe you've got stored codes. Sometimes codes are useful.

Left it at 2 degrees advanced. Backed it all the way to 0 and made no difference. I do not have access to a scanner. The ses light is not currently on.

 

[evilunclegrimace]

Left it at 2 degrees advanced. Backed it all the way to 0 and made no difference. I do not have access to a scanner. The ses light is not currently on.

With out a scanner you might as well run in circles and bark at the moon. You need to know what is going on before you can do an accurate diagnosis.

 

[phantom 309]

If the motor is too lean it will ping,.
I would think your tip in and part throttle tables need to be richened up,.
The camshaft may not be suitable either,. It could be making to much cylinder pressure,.static compression vs dynamic compression etc,.