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Tranny Rebuilt With Engine Codes.

The APP, is the accelerator pedal, which is essentially your TPS. The pressure to the tranny increases with TPS input. If its not then thats about the only way you could fry the tranny so fast. Although Ive not heard of one going so fast. The APP only needs 2 of 3 internal sensors in it to run fully functional. It will set the code but wont even turn on the SES light until a second fails, and it will limit power to the engine. If all three fail the engine will only idle.

I would more likely suspect the wire going from the PCM to the tranny pressure control solenoid being cut. That wire goes from PCM pin C6 on pin 32 pin connector on red/blk wire to pin C on the transmission connector, and the return is pin D on the tranny conenctor that goes to PCM pin C11 on lt blu/wht wire.

You can pull out PCM harness jumper the two pins together, then get under the truck and test ohms across pins C and D. Just to make sure there is continuity and no cut wires.

then plug PCM back in and turn IGN to on. Need to check the voltage on tranny connector pins C and D. Both should be close to 0VDC. Then start truck and check voltage at idle on pin C, and it should be about 6.5V. You can do that from under the truck on stands (if its stable) or extend the pin out from under the truck first with pin tips that will slide onto the connector. The return side might not show any voltage if not plugged in, but pin D should have 1.5V on it at idle (so it should be there when not plugged in). Otherwise if you want you can plug the tranny connector in and either poke through the insulation of the wires from either end or try to probe the PCM pin from the back while its plugged in.

Attached is are the manual pages that show this
 

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The APP is bad.....trust me....

Replace it with the one from your other truck and everything should be good to go unless the tranny shop F'd something up....
 
You can also test the APP. The APP should not be able to fry your tranny. It can cause it not to perform, but if you are able to increase RPM that means you are able to increase fuel. If your tranny is frying then the pressure is not going up even though the PCM is seeing higher TPS from the APP.

So then how is the APP only to blame? You cant increase RPM to fry the tranny if the APP isnt working.
 
If pressure control solenoid wire were cut, it will go to full line pressure. They default to the safer side. Like Buddy said, voltage across the two pressure solenoid wires should be around 5-6v at idle and should drop if you snap the throttle in neutral. It will drop down close to zero, like 0.1-0.4v under load in gear, dont try this if the trans is slipping, just do the neutral test.

You really need a scan tool to see what the TPS and trans is doing. But get the TPS problem fixed first before you try to drive it. You may have a bad PCM, I've had a couple go bad(guess the driver stuck), sending constant 12v(lowest possible pressure) to the solenoid.
 
Well i put the new APP in and it cleared the code and everything else works properly except the turbo. I swapped it out for a GM8 and i cant get any more then 9 pounds of boost even with the waste gate wired closed. It also sounds like a gas jobber the way it snaps way louder then before. any ideas????
 
Going back to tranny concern, does it feel any different than before, like it shift good now but didnt before? Did you have any tanny codes or issues before the last couple got nuked?
 
Tranny shifts fine now. You can sure feel it lock into O.D with that heavy duty torque. I did plug in the scanner and they are the same at the piller guage so its not clogged or anything. The truck also smokes quite a bit still, I have 2 GM8s from the extra engines i tryed both of them and they did the same thing..... We are like mind boggled about this. Unless im lucky enough to come across 2 bad turbos? Maybe the vains are sticking? i donno im gonna put on a holset HX35 as soon as i can find one. Just kind gay i have less power then before with a build tranny.......
 
In order for the APP to cause your stuff to be messed up is if it had two bad sensors. And that would do a lot more, like put you in backup fuel mode (limp mode), and throw two codes that would lead you right to it. If you drove high RPMs in limp mode then I guess maybe thats what was causing your problem, but that would have been some really terrible driving.

If you have tied the wastegate shut and cause a DTC 78, then its going to limit fuel tremendously and less fuel means less boost. Its surprising you would have that problem with a Heath tune, unless you code is for not enough boost at times. In order to have boost need pressure across turbo. So low boost could be exhaust leak preturbo from manifold or crossover. Or highly resistricted on the exhaust side of the turbo, like from kinked downpipe or a catalytic converter. Or your intake could be leaking if you didnt use good clamps on the silicone connection or forgot an intake gasket. Did you reuse the intake with the EGR on it and forget to plug the EGR ports?
 
You are running a Heath HP4 chip.

The only way you are throwing that code is if the MAP sensor on the intake is bad - I remember the wiring to that sensor being weird....I had to have the connector zip tied to the sensor to get it to make full contact...

Also, the previous owner had spliced in the MAP sensor wiring. May want to pull back the wiring loom and check it out.

BTW - I'm glad the APP cured the trans issues....
 
How are you keeping the waste gate shut? The truck had a Heath Turbomaster on it for a GM4 when you got it....
 
I put the newer 1997 intake on the engine. The differences are there is no egr ports in it.I have checked all hose clamps and pulled off all intercooler pipes to see if a rag was stuck in there or somthing. I'm going to post a video and show you guys what's going on. As for the egr I haven't changed and thing from last time.
 
Do you still have the wastegate solenoid plugged into the harness? Check MAP sensor and wiring....
 
The harness and solenoids are located at the rear driver's side head....the solenoid with a green dot is the wastegate solenoid...
 
Drivers side valve cover

Its still odd that you burnt up two trannys. There is no way an APP can cause you to burn up a tranny unless the custom tuning bypassed some fail safes. Either your trannys were ready to go, werent actually bad when you thought they were, or you had something installed wrong and now its right. What happened to the trannys for you to conclude they were fried, did they actually burn up?
 
buddy said:
Drivers side valve cover

Its still odd that you burnt up two trannys. There is no way an APP can cause you to burn up a tranny unless the custom tuning bypassed some fail safes. Either your trannys were ready to go, werent actually bad when you thought they were, or you had something installed wrong and now its right. What happened to the trannys for you to conclude they were fried, did they actually burn up?
Click to expand...

Oh yeah both of them were right f***ed he let me look at everything when he had them both apart. He said he had never seen anything that bad for a long time and both tranny were about the same for damage. I actually have all the old clutches and parts from the old ones in a box. As for the solenoid i checked it and its all plugged. Is the MAP senser beside it? Im going to pull the intercooler and run it streight into the engine to make sure the intercooler doesent have a hole or crack.......
 
chrisk1500 said:
You are running a Heath HP4 chip.

The only way you are throwing that code is if the MAP sensor on the intake is bad - I remember the wiring to that sensor being weird....I had to have the connector zip tied to the sensor to get it to make full contact...

Also, the previous owner had spliced in the MAP sensor wiring. May want to pull back the wiring loom and check it out.

BTW - I'm glad the APP cured the trans issues....
Click to expand...

Sorry for not responding Chris i must have missed this post on my I-Phone. Im going to check the wiring loom tomorrow. I used some hay wore to keep the wastegate closed. I tightend the turbo master right up and it dident work........
 
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