ignition timing on a 93 chevy 5.7

[Bob Barone]

I have a 93 chevy c1500 pick up when i time the engine to 0 degrees as required per spec the truck runs terrible coughs out  throttle body no power ect.

I took a timing light with advance adjustment on it and found out it only is getting 24 degrees at full advance so i added some timing to the distributer 10 degrees and it runs much better when i put my timing liht on after adjustment of dist. im now getting 34 degrees of total advance  at 3000 rpm but at idle it only drops down to 32 degrees and im getting some pinging when cruising in town and the trans is in 4th gear my question is is the icm  in the dist or the pcm the problem anyone have any ideas to steer me in the right direction

Thanks in advance 

Bob

[diyer2]

There is a wire on the passenger side of the firewall behind the black plastic piece that you have to disconnect to time it.

Google it maybe?

[Bob Barone]

I did pull the wire on mine its under the glove box i did that when i initially timed it to 0 degrees 

[LDM]

On 4/19/2020 at 10:05 AM, Bob Barone said:

I have a 93 chevy c1500 pick up when i time the engine to 0 degrees as required per spec the truck runs terrible coughs out  throttle body no power ect.

I took a timing light with advance adjustment on it and found out it only is getting 24 degrees at full advance so i added some timing to the distributer 10 degrees and it runs much better when i put my timing liht on after adjustment of dist. im now getting 34 degrees of total advance  at 3000 rpm but at idle it only drops down to 32 degrees and im getting some pinging when cruising in town and the trans is in 4th gear my question is is the icm  in the dist or the pcm the problem anyone have any ideas to steer me in the right direction

Thanks in advance 

Bob

Has this truck had the ECM tuning changed by swapping in a different chip?  If someone changed the settings there, then that would explain a lot of the issues.  The ECMs on these vehicles rarely fail but it does happen on occasion.  I would rule out everything else first though.

 

If no change in tune, I would start with the ignition system.  Failing ICM is common enough but when was the last time the distributor cap and rotor were changed, along with the plugs and wires? 

[riverbanks]

You could slowly,in small increments,back off the distributor,till pinging is gone,she's no spring chicken,gotta improvise

[Bob Barone]

I replace cap and rotor abt 6 mo ago have new distributor coming gonna change plugs wires cap and rotor and see what happens And to my knowledge no tuning has been done to the ecm  thanks for the reply's