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I think its time to put in the new ip, just making sure I dont miss the obvious

Before replacing the IP I would take that resistor wire harness off the IP. If it is still there it is connected to the OS on the IP. Give that a shot and see if it takes care of the problem.

Mine acted up like yours is and I unhooked the harness from the OS. It had less power and I had to crank the engine over longer to get it to start but the issues went away. So I ended up replacing the OS and it took care of the problem. I also was having the code 18 show up. I had 240,000 on the original pump when the os went bad.
 
doober said:
Before replacing the IP I would take that resistor wire harness off the IP. If it is still there it is connected to the OS on the IP. Give that a shot and see if it takes care of the problem.

Mine acted up like yours is and I unhooked the harness from the OS.
Click to expand...

Good point, did you try removing this OS filter and just plugging the engine harness into the OS?
Fixing truck 001.jpgFixing truck 004.jpg
 
It's right on top of the IP. You probably have to take the top half of the intake off to get to the other end of the harness. The harness is approx. 4 inches long. Just take that harness off, If it is still there, and plug the other end of the harness into the top of the IP. Throw the harness in your glove box so you don't loose it.

If that doesn't clear up your problem try unpluging the the harness from the OS and see how it runs. It might take more cranking to get it to start but once it starts see if the problem goes away. You might notice that it has less power with it unplugged but see if the rough running subsides. Mine was low on power but it ran good with it unplugged.
 
All of my grounds are good and most seem to have been replaced recently, cables look new and homemade.

I relocated the Filter to my glove box and it definately doesn't run better. Maybe even worse, hard to tell, it still shakes like no other when reved to 2000rpm and sounds rough goin down the road.

Reread my codes today and still had 33 and 78. I cleared them again.

Neither are IP codes but it still runs like crap cuts out, shakes, and knocks when reved. It hasn't died lately but thats only been a twice a week thing, already met its quota.
 
Did you plug the engine harness directly into the OS? Or did you just leave it disconnected. If left disconnected it will go into backup fuel mode, limp mode.

Do you know if it was timed properly in the past? You could try running the timeset on it from GMTDScanTech to see what its "base" timing is, and if isnt near 3.5 degrees it might be your problem. And your TDCO value may not be accurate.
 
I dont see why it would ever have been touched in the past 8 years (when the block failed). I doubt it got driven 8 years with this problem and not being timed. I may be wrong but it is just the way I look at it. For the sake of arguement I will get a screen shot of it with my old IP still on and check its timing.

I will check the timing when I put the new IP on, lol. I don't feel like getting stranded too many more times or missing anymore class when it was my IP all along and I had the chance to change it already.

I just pulled the filter off and plugged the harness directly to the OS. Didn't make it better.
 
tanman_2006 said:
All of my grounds are good and most seem to have been replaced recently, cables look new and homemade.

I relocated the Filter to my glove box and it definately doesn't run better. Maybe even worse, hard to tell, it still shakes like no other when reved to 2000rpm and sounds rough goin down the road.

Reread my codes today and still had 33 and 78. I cleared them again.

Neither are IP codes but it still runs like crap cuts out, shakes, and knocks when reved. It hasn't died lately but thats only been a twice a week thing, already met its quota.
Click to expand...

I'm not going to beat a dead horse here, but in case others are reading this:

Visual inspection of grounds is NOT enough. You MUST remove, wirebrush, and re-install each ground. These trucks do not have a central ground as most modern computerized machines do. There are multiple legs, and if one may the system can stall.

Or a braided ground strap may look alright, until you touch it.

Changing the IP may force you to change/fix a defective ground fixing the problem. Or it may not and the fresh IP may stall.

Most ground issues show their face around season changes as ambient temps change, especially cooler overnight temps.

It has been proven time and time again that ground Maintenance is a MUST for 6.5 owners. A yearly ritual.

1/2 a day with a wire-brush dremel ensures everything is in tip-top shape, and if it doesn't fix your problem, it most definately prevents future ones.

Rant over. A friendly reminder to all of us to go clean our grounds, as its much more fun to do it now, then to stall out in the dead of winter.
 
You would be very surprised what poor maintenance is done with these IPs at mechanics and dealerships. I would never assume someone did it right in the past. An IP that was not timed correctly and the TDCO was not set right can cause the DTC 18 and 34. So I would suggest taking a snapshot of it while its running warm, then run timeset and make note of the value in the actual timing, then run the TDCO relearn and see if it changes significantly from your first snapshot.
 
tanman_2006 said:
So I read the codes and my truck basically said HELP!!! :eek:

Multi problems, Here we go:
32-EGR Circut Error
33-EGR Control Pressure/Barometer Sensor
34-Injection Timing Stepper Motor Circut High
78-Turbo Wastegate Solenoid Fault

Did I miss anything?

BTW my IP only has 255,000 miles on it
Click to expand...

Another thought: Have you pulled the fuel filter out? May be plugged.

DTC 78 and 32 can be related if there is a problem with the: vac pump or lines pinched / leaking.
AT idle you should have 15" of vac in place of the waste gate. IE: take the hose off the waste gate and put it on the gauge.
If you disconnect the electrical plug on the solenoid the vacuum should disappear. If so you have other turbo / air / exhaust issues. If not the solenoid is bad.

Check vacuum at the pump is on both codes.
 
I didn't get around to changing my IP this weekend (too much to do on the farm). I couldn't do it properly anyways since my GMTD Scan won't work for some reason, i have sent an email to figure this out.

I did check and clean all grounds which had obviosly been done before as said before. All new grounds. I tightened my PMD allen screws friday before I headed out, no difference. Threw on a spare after driving 150 miles to get it with 1500# of feed in the bed. Spare PMD wont even start the truck. Grey PMD put back on good and tight.

I stripped as many parts as I could off of my spare engine. It is just laying in the bed of Ol' Blue, i dont have a stand.

Today I tried to check my vaccum pressure and didn't get squat at the turbo or where the EGR hooks up. Whats next? How do I check vaccum directly from the pump to rule it out and know if it is the solenoid?

Are vaccum pumps off of a 99 3500hd the same as my 95 Chevy Z71?
What is the best way to lift an engine so I can pull the rest of the parts?
 
Another, semi unrelated question. My spare engine has 12555506 stamped on it. Is this where the date is from? If so does anyone know what it is?
 
run the vacuum line directly from the pump to the wastgate actuator vacuum pot.

If it pulls it closed and you can't move it, it's most likely your solenoid that's gone bad.

My plastic lines are still relatively flexible, so I just pulled them off the solenoid and plugged one line into the other at teh rubber connector.
 
great white said:
run the vacuum line directly from the pump to the wastgate actuator vacuum pot.

If it pulls it closed and you can't move it, it's most likely your solenoid that's gone bad.
Click to expand...

Next question then, How in the heck do you get down to the pump, to hook the lines up directly?

I can see a line going up from the VP and the under the Lower Intake, this is a clear line, then I cant find it out the back. Running right next to this is my turbo actuator line, black line, coming from under the intake as well. Where do these hook up at on the other ends?

I forgot to check and see if I could move the actuator arm. Easiest test of all DUH!
 
tanman_2006 said:
Next question then, How in the heck do you get down to the pump, to hook the lines up directly?

I can see a line going up from the VP and the under the Lower Intake, this is a clear line, then I cant find it out the back. Running right next to this is my turbo actuator line, black line, coming from under the intake as well. Where do these hook up at on the other ends?

I forgot to check and see if I could move the actuator arm. Easiest test of all DUH!
Click to expand...

Well, if you can't do all that, disconnect the lines at the solenoid actuator and stick a vacuum gusge in the line. IIRC, you should get somewhere around 20 in/hg.

A mity vac on the vacuum pot wil tell you if the diaphram has gone bad.

If both are good, it's the solenoid itself or perhaps the lines have deteriorated.

Clear?

Mine are black and orange on my 98.

Sounds like you've had one replaced on you some time in the past.

If you don't have access to guages or a pump, just plug the two lines together at the solenoid and it's then running directly from the pump to the vacuum pot on the turbo wastegate.
 
great white said:
Well, if you can't do all that, disconnect the lines at the solenoid actuator and stick a vacuum gusge in the line. IIRC, you should get somewhere around 20 in/hg.

A mity vac on the vacuum pot wil tell you if the diaphram has gone bad.

If both are good, it's the solenoid itself or perhaps the lines have deteriorated.

Clear?

Mine are black and orange on my 98.

Sounds like you've had one replaced on you some time in the past.

If you don't have access to guages or a pump, just plug the two lines together at the solenoid and it's then running directly from the pump to the vacuum pot on the turbo wastegate.
Click to expand...

I have a guage kit but no pump. The guage is not reading anything at the actuator line. Where are the solenoids and the vaccum pot? Should the clear line lead to these (where ever they are)? Is this where the EGR line goes too?

Sorry about all the questions.
 
tanman_2006 said:
Threw on a spare after driving 150 miles to get it with 1500# of feed in the bed. Spare PMD wont even start the truck. Grey PMD put back on good and tight.
Click to expand...

Newer Grey PMD uses A Different pin-out or connector...If I rember Correctly....which is taken care of with the extension cable...

...which would explain why it wouldn't start...
 
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