06 Colorado RPM question

[06ColoZ71]

I have an 06 Colorado Z71 4x4 which I put 33" tires on. I have recalibrated the speedometer to show the correct speed. When I have the cruise control set on 60 - 70 MPH, the RPM's go up and down frequently when on a very slight incline. RPM's run at 1600 then jump to 2500, and when the vehicle regains its speed, the RPM's go back down to 1600. It's as though 1600 RPM doesn't have enough power to maintain 60 MPH on the incline (very slight incline.) Before changing the tire size, this didn't happen. How can I adjust the RPM so that it doesn't go below 1800 when cruising at 60 MPH? I'm guessing 1800 RPM might have enough power to maintain the speed.

[Bill@HPTuners]

you'll need to mess with the TCC stuff...sounds like the tc is unlocking/locking/unlocking.

[stocker2]

Whoah... man.

The rpm your vehicle turns at 60 miles per hour is fixed and is only based off your tire size, and gearing.

Even if you tell you tuner to make it look like the truck is running 1800 rpm at 60, it actually running 67mph or so at 1800. The only way to chage your RPMs are to change your tire size or rear end ratio. If your truck is running up to 2500 rpms, it seems like it is shifting into 3rd, changing the torque converter lockup setting probably won't help this. You are simply asking to much force at the wheel from a drive train that is way too long (3.73s, 33s), couple to a motor that is releatively small and needs enough mechanical leverge properly perform.

In addition your probably hurting your gas mileage because the low amount of advance that you will run at that low rpm with high manifold pressure.

[Bill@HPTuners]

you've never felt your converter unlock stocker?

[kabbott]

you've never felt your converter unlock stocker?

Thanks to hp tuners mine now feels like fith gear

06colo if you want the rpm's higher you can raise your shift speed so it does not shift into next gear untill higher speed,and you can also raise speed at which TCC locks.

What we need is PCM controled axle ratio,work on that would you HPT

[06ColoZ71]

If I raise my shift speed, do I need to make corresonding adjustments to my TCC tables?

In my shift speed tables, I have four tables - normal, cruise, performance, and hot. The normal and cruise tables are the same. How do I know which one my truck is using? Does it use the normal setting and then the cruise setting when the cruise control is turned on? I was going to copy the performance table into the normal and cruise table so I would get the performance settings no matter how I drive. Do I need to copy the TCC performance table onto the TCC normal and cruise tables?

[stocker2]

you've never felt your converter unlock stocker?

I got a stick, but the last auto I had would not unlock to the tune of 1600 to 2500. Going from 1600 to 2500 sounds like a downshift to thrid and a torque converter unlock together. At least that's how my last 4L60E behaved.

Performance setting is tow/haul mode.

Running with the torque converter unlocked isn't too fuel efficient.

[Bill@HPTuners]

I got a stick, but the last auto I had would not unlock to the tune of 1600 to 2500. Going from 1600 to 2500 sounds like a downshift to thrid and a torque converter unlock together. At least that's how my last 4L60E behaved.

it could be either...it would just be a matter of logging Tc lockup and what gear he's in.

[rgvsierra]

I have an 06 Colorado Z71 4x4 which I put 33" tires on. I have recalibrated the speedometer to show the correct speed. When I have the cruise control set on 60 - 70 MPH, the RPM's go up and down frequently when on a very slight incline. RPM's run at 1600 then jump to 2500, and when the vehicle regains its speed, the RPM's go back down to 1600. It's as though 1600 RPM doesn't have enough power to maintain 60 MPH on the incline (very slight incline.) Before changing the tire size, this didn't happen. How can I adjust the RPM so that it doesn't go below 1800 when cruising at 60 MPH? I'm guessing 1800 RPM might have enough power to maintain the speed.

i was going to ask this same question
altough i have a 3:42 rear end with stock tire size on the offroad package on my canyon crewcab and it does that stuff constantly, i think its just a matter of doing what foff67 said, just havent got around to loggin it.

[06ColoZ71]

I did some tuning and it runs fine now. I copied the performance table onto the normal and cruise table (since I don't know which one it it using) for both shift speed and TCC. Truck has more power and maintains its speed with cruise control on. RPM's do run higher and I have to go faster to get out of 3rd, but it's tight and responsive now. A quick check showed 19 MPG city.