93 3/4 ton pinging

[dcarreno2006]

i have a 93 Chevy 3/4 ton pinging. i Know thats its my timing being advanced for some reason. I just dont know why its being advanced or whats causing it. The truck ran fine before this. Its my driver and I retarded the timing to get the pinging to go away for now. Now you can imagine how its running for now. Can some one point me in the right direction.

[MT-2500]

Originally Posted by dcarreno2006

i have a 93 Chevy 3/4 ton pinging. i Know thats its my timing being advanced for some reason. I just dont know why its being advanced or whats causing it. The truck ran fine before this. Its my driver and I retarded the timing to get the pinging to go away for now. Now you can imagine how its running for now. Can some one point me in the right direction.

Is egr valve working?
Have you checked or set base timing?

[j cAT]

Originally Posted by dcarreno2006

i have a 93 Chevy 3/4 ton pinging. i Know thats its my timing being advanced for some reason. I just dont know why its being advanced or whats causing it. The truck ran fine before this. Its my driver and I retarded the timing to get the pinging to go away for now. Now you can imagine how its running for now. Can some one point me in the right direction.

if you have lost the EGR operation which can be electrical, plugged intake ports, /or defective valve you will get detonation [pinging]. the egr sends exhaust gases to the intake to control emissions and reduce combustion temps...

with high combustion temps beyond the spec. the fuel ignites too soon and as a result the engine looses power and makes loud noises..

retarding the timing delays spark, use of high octane fuel, slows the fuel from igniting . but as you know this kills your power..

[dcarreno2006]

the egr valve is fine but i think the egr solenoid is bad. Ill get one tomorrow and see if that fixes it.

[j cAT]

Originally Posted by dcarreno2006

the egr valve is fine but i think the egr solenoid is bad. Ill get one tomorrow and see if that fixes it.

put a meter on it see if you have coil resistance / also bypass the controlling solenoid it may be the sol valve is plugged up..

[jdmccright]

You should include your engine type and mileage as well to help us with diagnosis.

Might have some carbon build-up on the valves and piston top, too, resulting in hot spots and increased compression that prematurely ignite the mixture. A good engine cleaner like Seafoam or Chevron Techron can help redissolve it. Multiple treatments may be needed for severe deposits.

You can also try the "steam cleaning" procedure of slowly sucking in water through the main vacuum tube. Please search for the procedure elsewhere in AF for all the details as doing this incorrectly can damage the engine!

Good luck!

[dcarreno2006]

the egr valve is new so is the egr valve silonoid. I know the egr port is open. But I still cant figure this out. the engine is stock it has 150,000 miles. Its also missing. Can it be that the miss is causing the computer to advance the timing and thats causing the pinging. I cant figure out the miss eather. it has new plugs and the cap and rotor look fine. In need of help. Its a 5.7

[tblake]

What brand and part number of plugs did you install?

[j cAT]

Originally Posted by dcarreno2006

the egr valve is new so is the egr valve silonoid. I know the egr port is open. But I still cant figure this out. the engine is stock it has 150,000 miles. Its also missing. Can it be that the miss is causing the computer to advance the timing and thats causing the pinging. I cant figure out the miss eather. it has new plugs and the cap and rotor look fine. In need of help. Its a 5.7

did you with the engine at idle force open the EGR valve ? the opening this valve at idle , should cause the engine to stall..if not you must find out what is plugged up...usually the intake passageways..I have had to do this on many of these GM older V8 engines...

just to recheck your issues pinging under load ...engine runs fine at idle...

[dcarreno2006]

I checked the egr valve by pushing it in at idle and it tried to die so i know the passage ways are open. Its idles ruff cause of some miss that I'm dealing with. The plug I put in are autolites. When i slowly give it gas you can really tell the miss. I put it back in time and it still misses and pings. No ping at idle.

[j cAT]

Originally Posted by dcarreno2006

I checked the egr valve by pushing it in at idle and it tried to die so i know the passage ways are open. Its idles ruff cause of some miss that I'm dealing with. The plug I put in are autolites. When i slowly give it gas you can really tell the miss. I put it back in time and it still misses and pings. No ping at idle.

with the EGR to be operating correctly then check out the distributor for bearing wear..

I would have used the a/c plugs ..most find these are the ones with no issues..

[MT-2500]

Did you set base timing in bypass mode?

[j cAT]

Originally Posted by dcarreno2006

I checked the egr valve by pushing it in at idle and it tried to die so i know the passage ways are open. Its idles ruff cause of some miss that I'm dealing with. The plug I put in are autolites. When i slowly give it gas you can really tell the miss. I put it back in time and it still misses and pings. No ping at idle.

how are you doing with that pinging issue ?

[dcarreno2006]

the miss I have is due to a blown head gasket, Its blown in between cylinders. I did a leak down test and my number 4 and 6 cylinders are blowing into each other via the head gasket. I guess it gives me something to do next weekend and it doesn't cost to much. Ill keep you posted.

[j cAT]

Originally Posted by dcarreno2006

the miss I have is due to a blown head gasket, Its blown in between cylinders. I did a leak down test and my number 4 and 6 cylinders are blowing into each other via the head gasket. I guess it gives me something to do next weekend and it doesn't cost to much. Ill keep you posted.

that type of failure I would have the head checked for distortions .. have you had any overheating ever with this engine ?