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Discussion Starter #1
Looking for some input on a truck I've had a few months. It's a 98 12v cummins:smokin: 100hp injectors, #4 fuel plate. Turbo off a newer (not sure what year) truck. It runs great, good power. The issues I'm having are with EGTs. If I'm pulling a rig ANY hill starts the climb in temps. At 45 mph and literally 1/10 to 1/4 throttle, just pulling the grade I'll be at 1300+ at 55 on flat ground with the cruise holding it steady, I will still be 900-950... If I mash it, it will peg my pyro at 1550 in less than 2-3 seconds.

While cruising or going up a hill at 1/4 throttle and 2000 rpm, there is berry little to no smoke out the exhaust. If its to the floor it will smoke but it definantly isn't rolling a 10 foot black cloud...

I am beginning to believe that perhaps my pyro is bad? Any one else seen a cummins with temps this high and no smoke? Ideas? Thoughts?
 

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boost pressure?

turbo is probably too small
 

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Discussion Starter #3
Interesting...

When I bought the truck about 6" of the boost gauge hard line was broken off. I put a piece of vacuum tube over about 6" of each end and the gauge only reads about 6-8psi. The truck makes good power, more than my old chipped 24v and probably more than my buddy's common rail. The turbo is loader than any other cummins I've owned (4 other trucks) I attributed the low reading to the vacuum hose and with the power it makes and the noise I figured it was good...

Waist gate stuck open a bit maybe???
 

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You might want to check for boost leaks and press turbo exhaust leaks also. I would think you should be in the 30+ psi range.
 

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You do realize you actually have to TUNE the truck, especially after you put in injectors. :shaking: The 12v isn't like new trucks where you put injectors and a program in and it runs fine, you gotta do the tuningi yourself.



First, as others suggested look for boost leaks. I'm guessing since you said your turbo is off a newer truck its probably an HE351cw which should move more than enough air for your setup. After you've ruled out a boost leak start adjusting your AFC and star wheel. Its probably a case of a boost leak and your low boost fueling level being WAY too high with those sticks. What delivery valves are you running? How about your timing?
 

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Discussion Starter #6 (Edited)
Maybe you missed the part where I clearly explained that I just got this truck a few months ago.....:shaking: I didn't do any of the work to it.

I'm going to verify boos pressure first and go from there. It makes a ton of power and I'm having a hard time believing its only making 8psi...
 

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Gotta be making more than 8psi, i make that much pulling out of my driveway.

I just went through abnormally high egts with my 06 6.0. I pulled the turbo off, rebuilt it, still had problems. Mine ended up being an intake leak. I know nothing of the 12v, but we ended up pressurizing the manifold in my truck through the map sensor until we found the leak. Mine ended up being the egr valve gaskets which I know you dont have, but it could still be a leak in there. My egts were exactly like yours, completely stock, pulling out on a road at 1/4-1/2 throttle id be at 1250*.
 

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Yep the california 96-98 12v's had egr. I'd remove it asap, if your not in a smog county. Those clog up the intake with soot, ive litterally taken handfulls out of the intakes of those trucks. As far as high egt's, what size exaust is on the truck? does it still have the CAT on it? stock airbox? radiator/intercooler clean? if you had a big enough boost leak to only have 8psi, it would run like shit and smoke like a frieght train.
 

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try pulling the intake horn/ grid heater off and see how clogged your intake is. I'm meaning the valley into the head itself. If your boost guage is tapped into there, it could be clogged with soot as well giving you a false reading.
 

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Yep the california 96-98 12v's had egr. I'd remove it asap, if your not in a smog county. Those clog up the intake with soot, ive litterally taken handfulls out of the intakes of those trucks. As far as high egt's, what size exaust is on the truck? does it still have the CAT on it? stock airbox? radiator/intercooler clean? if you had a big enough boost leak to only have 8psi, it would run like shit and smoke like a frieght train.
Ah - my '96 was a 49 state truck.
 

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Discussion Starter #15
Ok, do I got a new gauge and line, if I mash it it makes ~30 psi, while cruising down the freeway towing the rig it's making ~10...

Is there anyway to test the pyro probe? Maybe pull it out and put a propane torch to it and see what it reads?
 

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Ok, do I got a new gauge and line, if I mash it it makes ~30 psi, while cruising down the freeway towing the rig it's making ~10...

Is there anyway to test the pyro probe? Maybe pull it out and put a propane torch to it and see what it reads?
Sounds like you are just plain putting too much fuel in. Any It needs to be tuned down a little. Or just keep your foot out of it. I would read up on tuning the p-pump. I'm not familiar with them at all.
 

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You need to positively identify your turbo, and then make some fueling adjustments or swap the turbo for something else.
 

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You need to positively identify your turbo, and then make some fueling adjustments or swap the turbo for something else.
This^^^^^^^^^^^

Sounds like you are throwing a lot of fuel and need more air
 

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Too much fuel and kinda sounds like you're in the wrong gear. What are your egt's around 2100-2300 when pulling a hill?
 
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