Engine cuts out in reverse

[Turbine Doc]

Yes they did Thanks.

"They did ??? who did the timing reset???

If at a "Stealership" and not a 6.5 knowledgeable tech, they may not have done it correctly. I have been having oddities ( rough idle, hard start when cold, and rpm jump/stumble in reverse) in mine after last GM dealer IP install a couple of years ago, my MT2500 scanner display went all black, so I did not have a tool to do it myself.

I found a display before Christmas last year, I finally installed it today, I commanded time set (where desired goes to 0 deg. computer control out of the loop to see what base timing was at, truck died and would not restart, timing was too retarded, I shut down engine, loosened IP mount nuts to "snug" bumped IP to driver side (advance) with IP turning tool, torqued top nut full, restarted truck, and it idled fine in commanded time se, with timing now at 4.6 avg. vs factory spec of 3.5 in commanded time set mode.

Took it out of time set, and let engine warm up to full operating temp 180F ECT, shut off truck then key on only with APP to floor for 1 minute, then turned off ignition for 1 minute, restarted- engine stumbled a moment, while PCM "learned new TDC Offset. With mechanical TDC set "base timing in commanded time set at 4.5 deg. avg. I have found that puts the TDCO once learn has been properly commanded to "sweet spot" of -1.5, vs. -.75 factory, truck IMO runs much improved with -1.5 TDCO setting. Warm weather but seems to be starting better, definitely idles better, have not road tested that will happen tomorrow, but knowing my 6.5 as well as I do; it revs like it should closer to what I know it should be.

If a dealer is using a Tech 2 tool they have ability to bypass the key on/& APP to floor then key off to command the TDCO learn, but even with T@ tool they still have to be >170F ECT for the learn to be accepted (also no DTC codes present). I prefer 175+ ECT because if temp drops below 170F ECT to may not properly respond to learn command as permissive for learn falls out.

So if everything tried thus far has not worked I'd find someone that really knows how to time a 6.5 look at it, newer scan tools from what I have looked for before I found the MT2500 display for mine don't do it. And since cost for a tech 2 still carries a premium, I thought I'd be money ahead to fix my old MT2500, it was $50 for New old stock display, vs. +$500 for new, or used but should be good Tech 2.

 

[Turbine Doc]

Found a picture online. it's the part plugged into the IP with the purple and beige wires. remove it if it's still there and toss it to the trash can.

View attachment 93059

That "Block/noise filter" is on the OBD-I IP's not OBD-II 96+ years trucks, some have taken off without incident others it has hurt running without them, all I have ever run is OBD-II so I do not have a lot of "been there, done that" on OBD-Is other than to help others that have them.

 

[ak diesel driver]

Good to see you around Tim. My 96 had the noise filter on it

 

[Turbine Doc]

Thanks for the welcome;

I wonder if it was a late 95 build but sold as 96, my 98 is late 97 build but listed as a 98, there was a crossover if memory serves correctly where they had the filter as you said in yours. I'll have to look up in my library of old 6.5 info; as I think Diesel Page (original 6.5 web site) there was an article written about that filter to keep/not keep and years one might expect to see them, also could have been on the IP of a specific vintage. Long time since I've had to recall it, and memory isn't quite what it used to be.

 

[MrMarty51]

Thanks for the welcome;

I wonder if it was a late 95 build but sold as 96, my 98 is late 97 build but listed as a 98, there was a crossover if memory serves correctly where they had the filter as you said in yours. I'll have to look up in my library of old 6.5 info; as I think Diesel Page (original 6.5 web site) there was an article written about that filter to keep/not keep and years one might expect to see them, also could have been on the IP of a specific vintage. Long time since I've had to recall it, and memory isn't quite what it used to be.

I have read posts by you and was always in my mind that this guy knows some stuff.
Thank You for returning.

 

[Turbine Doc]

Thank you for that, I've always been a little OCD about knowing machinery I work on/own, plus many nights staying at Motel Sixes helped if you remember that old commercial

 

[MrMarty51]

Thank you for that, I've always been a little OCD about knowing machinery I work on/own, plus many nights staying at Motel Sixes helped if you remember that old commercial