It has stumped many a diesel mechanic!!!

[Huntgfish]

My '94TD is hesitating after all my modifications, when I take off fast or going to pass someone and accelerate quickly up to 65 mph (2k-3k RPNs).

The ses light comes on and off with just a flinch of the accelerater at these speeds (even before the mods). It also turns off the cruise at any speed when the SES flashes. I brought it by the shop to check the codes, they said it showed code 111 which after I referenced it, said no known code. Thought maybe the Turbo master was adjusted to high, but I restricted it down to the lowest setting and that was not the problem.

I have had in two different diesel mechanic shops locally and is stumps them all, they say it is not throwing any codes when connected to the computer.
I really could use some of yall's expert advice on this one. Especially, since I just had the injectors changed with Heath's HOs, turbo master, max e tork, and the vacum pump pulled off along with new glow plugs.

It feels like having a woman around that will not quit nagging! HELP!!

Thanks in advance,
C Holder

[TAG]

sounds like you are losing a main ground to the ecm when the engine moves under load. several ground circuits are at block in engine compartement. check right rear manifold stud.

[Huntgfish]

I checked TDP for locations of grounds before I brought it by the shop the last time, and asked the mechanic to check the locations, said they were ok, but that does not mean he actually did it. I will check it out myself.
Thank you for the suggestion.

[TAG]

hook up voltmeter between computer case (behind glove box) and battery negative post. drive truck & watch voltmeter when problem happens. rise in indicated voltage on meter means not enough capacity on ground circuit.

[Huntgfish]

I will try that, thank you for the advice.
CHolder

[Huntgfish]

What is the solution if there is not enough capacity on the ground circuit?

[TAG]

just proves you have a bad ground, if that is the case you need to start checking & cleaning grounds or run a new one.

[Turbine Doc]

For starters try to install another main ground, get a #4 double ring lug end batt cable hook 1 end to the alternator mounting bracket bolt, and the other to the frame somewhere, GM hides the main engine to frame gnd strap generally back by the starter, you can't see it well; if broken or corroded hard to know it until looking for gnd faults.

My 90 gasser had this problem engine to frame cable/strap was broken, & I kept having charging "issues", found the broken strap after observing the underhood trouble light go brighter when connecting my CB radios gnd, installed the bat cable and fixed the problem, ever since I install same setup on all my rides

[Huntgfish]

So does that also solve the problem if the cable strap is broken?

[Turbine Doc]

Multiple grounds in GM trucks have to check all, but losing the main gnd strap does not make the truck happy, as hi current draw stuff like starter headlights etc will seek gnd in smaller stuff like 18 gauge control circuit grounds, overstressing their need for a good ground, check the main gnd 1st then check the rest. starting with PCM & ign switch gnds

[Huntgfish]

Thank you I continue my PI work!

[gmctd]

Checked your previous posts for any further info, so comes the inevitable question(s) -

What is the injection pump history?

When was timing set changed?

[Huntgfish]

I bought it from my dad, he purchased it with 80k miles and said two IP replaced by dealership before he bought it, since then, he has had the FSD replaced once.
Seems like they (Chevy) should go back to the drawing board to fix the FSD and IP problem for good. But, then it does not seem their would be very much traffic on TDP without these problems!!

[Huntgfish]

I do not think he or I know the answer to the later question of when the timing chain was looked at or serviced.

[gmctd]

You definitely need to determine the timing set status - 190k is 100kmi past due if it is original.
Needs to be done as a set - chain and both sprockets.

Inj pump can be changed without removing front timing cover, so it's a good likelyhood cam and ip timing are out of spec'ed tolerance.

Depending on mileage since last inj pump replacement, it likely needs to go, also.

[Huntgfish]

Thank you for the info, those are some ideas that I have not read on the TDP yet!