Duramax shop suggestions

[str8axleguy]

Hey all, I have a tuned 07 Chevy with the duramax that I’m kinda fighting an EGT temp issue on, truck will hit 1300 pretty easy when towing my fifth wheel toyhauler, temp will continue to climb if I stay in it without forcing a downshift. Truck has banks intercooler aftermarket down pipe and full 4” exhaust. Not sure if this is normal or if I possibly have a boost leak somewhere causing elevated temps. Anyway looking for a shop or individual to at least check it and advise. I’m in Willard but basically any wasatch front area would be fine. Thanks in advance!

 

[Tonkaman]

Those trucks have a known injector failure problem. I can’t remember, but I think that is one of the first symptoms since it starts to over fuel.

I don’t have any great recommendations on a shop. I do watch Dave’s Auto Center videos and feel like they at least look legit.

 

[str8axleguy]

So I do have an edge CTS for gauges and can check balance rates and they are in spec, but not sure that’s the end all be all to injector health .🤷‍♀️

 

[Pile of parts]

When I had my '01 Dodge with an edge on it, I had to drive by gauges and not by what it was capable of doing. I did have a full 4"exhaust but just stock intercooler. It was a manual transmission and I would have to downshift or back out of the throttle as well. Not due to gearing or power. EGTs would easily exceed what they should but the truck was happy to keep on building power if I let it. I think you could throw a lot of money at it, chasing the next thing. I chose not to and just lived with what it would do - which was honestly, plenty.
I'm guessing you don't have anything wrong with the truck. How much do you want to spend for how much more???

 

[Rot Box]

It could be as simple as more air or less fuel. If you back off the tuner to stockish settings do the egts run a little cooler?

As for shops I might give Moonlight a call over here in cache valley if need be, but I’d rule some things out first.

Curious, is your truck the LBZ? I know there was a half year in there somewhere.

Andrew

 

[Rot Box]

On that note I made a really simple boost leak detector for my 7.3 using a 4” pvc pipe cap. Clamped it into the turbo inlet, turned my regulator on the air compressor down and fed it roughly 20 psi. With some soap and water I quickly found a boost leak on mine in a very unlikely spot. Explained my low boost/high egts at the time.

I’m not super familiar with the duramax but I assume you could do something similar if you want to remove your intake and such?

 

[str8axleguy]

So I’ve done the boost leak test on it, fixed a leaking boot at the intercooler bottom. I have to keep feeding air, not sure I’m doing it correctly but I don’t hear any other leaks. Mine is an lmm, so it had dpf stock but it must have fallen off. I work in cache valley so I could easily talk to midnight, thanks for the recommendation

 

[str8axleguy]

So I dug into this further and stopped at moonlight with a coworker. They said basically they would have to see it. Asked about some common issues and even asked about a bad EGT probe. Said when they go out the readings are usually way off. Coworker suggested after we left to try a probe replacement before taking it for diagnosis and I decided to try it just to rule out. Well turns out the EGT probe from edge was bad showing high readings, 60 dollar probe and I can stay in it on highest settings and stay well under safe temps. So I obviously had an inaccurate exhaust probe the whole time.