Ok guys, you probably have read my first post on my 94. Now here I am getting more and more furious with my truck.. lol Let me tell you what I did and we will go from there. First off, I sent my injector pump off to have it fixed by SSDiesel supply, I bought injectors, a chip, 4" exhaust at the same time. So I installed all the new stuff and I was upset with the result, It didn't run any better, so I tought myself what needed to be done, and in that I found that the injector pump was never broken. It all started with codes 34 and 88. Being ITS motor and TDC offest error. Well, after spending $2000 on parts as you would be I was NOT happy. I finally figured out that the code 34 was from the timing being so far out the ITS could not compensate, the code 88 was from a bad ECM that would not learn the TDC offset, so I installed a new ECM, and my boss bought a TECH-2, I learned the TDC offset, now to the real questions. How can you change the TDC offset and what is the purpose of it? Because the truck runs NO different from when it was or wasn't learned. It is set at -1.23 and I cannot figure out how to change it. The truck is a slug from Idle to about 25-2800 then its a "rocketship" for a 6.5 truck or at least I think. The desired and actual pump timing is right there at Idle, about 4.5-4.7. I installed a new lift pump, new fuel filter etc etc. The other problem is when I "free rev" the truck in park, it white smokes and misses, but driving down the road it doesn't do this. Now I'm talking warm, cold, anytime on that problem. I think that I am getting really really close on this thing and it's killing me and my wallet trying to figure it out. Anyone wanna buy a truck? lol... It has me so pissed off now I HAVE TO FIX IT... lol to teach it a lesson. Well, I'm sorry for putting such a large post, but I lacked information last time I did post, and also I would like to thank all of you for taking time to help! James

What did you do about the timing chain\sprocket set?


Original?

Don't you Physically move the pump and then relearn to move the TDC offset? I run my timing toward 8.0 actual.


Worn timing chain works better a little advanced.

I replaced the chain and gears, but the funny thing about that was, the new set was about as loose as the old one??? had about 1" slop before and about 3/4" after.... Wondering if my block is broken. I didn't try to advance the timing any, thought she may set a code.. lol I wouldn't know cuz the MIL is burnt out from being on so long lol I will try advancing it a little and see how that works.

I couldn't figure out how to do it on the tech-2 we've only had it for a day, but someone out there can tell me how http://www.dieselplace.com/forum/smileys/Big Smile.gif then I'll probably be happy!http://www.dieselplace.com/forum/smileys/Clap.gif

What brand timing set?

Was a Cloyes set, My buddies 93 6.5L has the same chain problem on a new short-block sitting on the stand.. trying to figure out if the gear drive will solve this problem? Or is something else wrong here?

I just replaced timing set on my 94 6.5 as well, My set was from Federal Mogul, it was definitely worn out, almost an 1" of play with the old set, but the new set fit nicely, not tight, just enough play.


With your OBD-I truck, you want to set the TDC Offset between -0.75 to -0.25.

The axle pins wear, alowing chain length to increase, and the chain wears the effective diameter of the sprockets, allowing for loose chain fit.


The chain and camshaft and crank sprockets must be replaced as a set.


Seems as tho some new replacement sets may be loose at installation - nothing can be done about that.


My replacement set was as loose as the 5-year old factory set, but I don't know the actual mileage on the oem set.


Iirc, oem timing sets are Morse, double row, but not true roller chain.


The gearset fit with minimal backlash, as specified.


What I like about it is - remove the oil filler tube with engine running, and there is no sound of a chainsaw across an iron pipe.


That sound - like a loose chain was eating into the aluminum timing cover - was why I replaced the oem chainset.


Got the same sound with the replacement set, so I switched after a couple years, during some exploratory troubleshooting.


Not advocating it, just relating my experience.


But, I like the gearset.


Anyway, back to your problem - what chip did you go with, and are the new injectors stock, hi-flow, or hi-pop?Edited by: gmctd

Try retarding your pump a bit.

gmctd, the injectors are stock re-mans from SSDiesel supply, and it is a Hypertech chip. I did bump the timing up to 6.8-7.0 on a 4.8 desired (on my MT-2500 snap on) and it seemed a little better, but man, It still only runs good from about 2500 to redline. The gearset was replaced along with the chain too, just in case you were wondering

You'll need to do several runs with the MT-2500 to accomplish this -


Check your fuel rate from 1700-1800 up to when it starts pulling hard.


Should be min 63mm (stock oem) up to maybe 70mm - don't know what Hypertech's goals were.


Then check your Wastegate Duty Cycle for min 67% to start, observe it up to where it starts pulling. DC will drop to maintain steady Boost as exhaust energy comes up


Then check Desired and Actual timing numbers during a run.


Being unfamiliar with Hypertech's goals makes it difficult to give you any numbers to look for. May be simplest to reset to oem 3.5deg, and start from there.


Fuel Rate, WG duty cycle, and Timing compared to Boost levels should be a start.


Edited by: gmctd

Superpro82


Give me a call at 317-326-4296 and I can walk you through the process. Its not hard but I can't explain it that well in print.





Greg