Set IP Timing "Stock" or "Modified" ??

[ol9465er]

Hello...

I have been searching TDP for a while looking for help re IP and TDCO timing and have found much info but not the exact answer I am looking for.

I have the GMTDBasic software and found: "Injector Timing Desired" is 8.7; "Injector Timing Measured" is 8.6 and the TCDO is -0.53. (Factory specs are: +3.5, +3.5 and -0.50.)

My truck is completely stock with 208K miles but since I changed my IP (1.5 years ago), and had a GM diesel mechanic set the timing, my truck has never seemed to have the same top-end power, bottom-end seems fine. Could this be from the 8.7 and 8.6 timing?

Should I set the timing to completely stock settings or should I leave the IJ timing set TDCO to the -1.94 that I see in TDP. If it should be changed I would purchase the GMTDScan software to do this.

Above all though, I don't want to do anything too harsh for the ol' truck.

Any help appreciated.

Thanks,

[Warren96]

I set mine to 1.94 about a year ago, and cant believe it's the same truck. If I was you I would get the GMTD scan software and try it yourself. Yes, maybe it does rattle quite a bit when its REAL cold out, but with the software you can dial it back to were you will feel more comfortable if you prefer. Some members of the ''Page''have dialed it back to 1.50 to avoid that ''marbles in a can '' sound when you start it cold, but not me, I am addicted to the improved throtle response. Have you had the truck since it was new? One member has stated that the timing chain can stretch in as little as 60 or 80 thousand miles and should be replaced to keep it from running like a slug. I hope this has answered your question. Get back to us and let us know what you decided.

[ol9465er]

Thanks for the advice. Did you also have your IP timing set to something other than OEM at 3.5?

[JohnC]

Do the TDC offset learn and see what you get. If it's not close to -1.94, move the pump and repeat. Everything else will fall in place by itself.

[Warren96]

Yes, like John said if your current offset is .5 , then you would advance the pump timing a hair and check the offset again. If you are turning it in the right direction the offset will increase to say 1.25 rinse and repeat until you see the 1.94 float by. Setting the offset is the easy part, installing the software on your laptop is harder. Engh helped me through that.