Towing like crap

[02duramax]

I have a 2002 duramax with cold air intake and 5” mbrp exhaust. 35” tires. It has efi live, I was told it has a fast 100 tune. But here’s my problem, it tows like shit, can’t go up hills at all. Slows way down and I have to majorly down shift to keep it going. Trailer is only 5000 lbs. Can I get some help on what to do. I got a divorce and the ex got my EFI live V2 tuner, she ain’t gonna let me have the V2. I want more power and better towing.
What are my options?


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[Chevy1925]

what are egt's when you slow down? boost?

without your V2 and a good way to watch other parameters, this is going to be very hard and blind for us to figure out.

 

[2004LB7]

2x ^^^

you need to tell us your boost numbers, fuel pressure, fuel rate, engine rpm, etc. we can't do much without it

you maybe able to help with regearing the rear to some 4:10 or 4:30s. those 35" tires aren't helping much

 

[Bdsankey]

35s, 100hp tune on a stock turbo, and stock gears will ALWAYS be a bad time towing. You will need, like the others have said, some way to watch parameters or datalog to review and pinpoint the issue. It could be something as simple as your ECM needs better quality tuning or you could end up with a boost leak/weak pump (possibilities are endless).

 

[02duramax]

I don’t have gauges.


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[Bdsankey]

I don’t have gauges.


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Don't take it the wrong way, without information anyone here is just pissing in the wind so to speak.



For example the truck could have any of the following issues or even something else. The truck could have a tune that doesn't tow well, could have a boost leak, could have a weak CP3, could have weak injectors, could have injectors that are hanging up, could have a stuck wastegate, could have a drive pressure leak etc.

 

[08lmm72mm]

Are you having the issue towing in 'D' with or without tow/haul on? How fast are you towing? What rpm are you towing at on flat ground?

 

[02duramax]

I forgot to say I have a lift pump too. Yes I tow in D , but I take off with tow on


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[1FastBrick]

Not sure where you are located but maybe someone in your area can has EFI Live and can get some logs for you.

 

[08lmm72mm]

I forgot to say I have a lift pump too. Yes I tow in D , but I take off with tow on


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How fast and what rpm are you going while towing?

 

[02duramax]

Could someone point me in the right direction to get the efi live tunes


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[02duramax]

I just acquired a cts2 monitor so I can see the readings. Gonna install


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[77cruiser]

5000 lb. trailer shouldn't faze it much. I pull 14000+ with my 04 with a 30hp tune, 4th gear on most hills.

 

[02duramax]

That’s my thought, gonna hook up cts2 monitor and log some parameters, but I don’t have my trailer hooked up at this moment.


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[2004LB7]

5000 lb. trailer shouldn't faze it much. I pull 14000+ with my 04 with a 30hp tune, 4th gear on most hills.

what sized tires do you have?

 

[02duramax]

35’s


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[77cruiser]

265/70/17 I think they're 31.5, not as big as the OP.

 

[Bdsankey]

265/70/17 I think they're 31.5, not as big as the OP.

I think that's the point we're all trying to make. There is an issue with the OP's truck somewhere. Now that he has a way to log/view PIDs we can start diagnosing it. These trucks in OEM form have no problem with the loads he's talking about and even significantly larger loads.

 

[2004LB7]

if the tune doesn't account for the 35" tires then it's shift rpm will be two low and HP and torque will suffer. thus bad performance. it can be done with a good tune and that tire size, bit even a good tune will not work well if there are other issues such as low boost or fuel pressure

 

[Chevy1925]

a tcm tune wont fix this. i ran a stock TCM tune for many many years on 3.73s and 37s pulling loads of the same weight or little heavier. thats back when i was still just a single stock turbo. i wanna say that tune was around the same as he has or less hp. 5th gear held most hills but 4th was needed near the top of if speed fell under 60-65 iirc.

not being able to watch EGT's on that big of a tune is not good though... glad he has a CTS now to monitor.