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Factory Rev-limiters

Thumper

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Thumper Enthusiast

Thumper

Posted
Posted

Title and description pretty much says it all.

 

I just took my 2002 2500 Avalanche in for some warranty work since it runs rough on acceleration and fuel mileage is real bad (7).. I romped on it and when it got up to 4500 RPM is started really choking and puking until about 4700 and then it reved freely to 5200. Mind you, I rarely romp on this truck but I could not even outrun a newer Isuzu Trooper on a freeway on-ramp! (2 lanes narrowing to one about 1/8 mile away).. Guys - that Isuzu about kicked my butt!!! If anything I got the jump on him from the red-light!

 

Something is wrong with this truck. The service writer at the shop just called and told me that the rev limiter on that truck is 4,000 RPM and it will not go any faster than that. Seems odd that I was able to get it to 5200 if that was the case...

 

Does anyone know what the factory rev limiter is set at for this engine and the 6.0 as well? I am just about ready to trade her in on a Crew-Cab 6.0 if this is the way this truck is gonna be.

 

Thanks!

AZ1500 Enthusiast

AZ1500

Posted
Posted

The dealer is stroking you. If the rev limiter was set at 4000 rpm, the engine would never be able to produce it's max rated hp. Go to the service manager and/or the general manager and don't let up until they find the problem. :)

496Cubes Enthusiast

496Cubes

Posted
Posted

The 8.1's rev limiter is set at 5,000 RPM. The rev limiters are not only for neutral or park, it's all the time. I would guess the 6.0 is at least 5,000 or higher.

tmf6902 Senior Enthusiast

tmf6902

Posted
Posted

Yeah I know I have had mine well above 4k many times.....I havn't really watched the shift, when WOT, but I am pretty sure the needle goes all the way before it shifts.

Thumper Enthusiast

Thumper

Posted
  • Author
Posted
The dealer is stroking you.  If the rev limiter was set at 4000 rpm, the engine would never be able to produce it's max rated hp.  Go to the service manager and/or the general manager and don't let up until they find the problem. :smash:

I am a wrench myself (30+ years) but I typically don't like to work on my own stuff when it is in warranty..

The service manager told me that they found the problem. Apparently the programming in the ECM was not picking up the crank trigger therefore the timing was off.

 

Yup - more smoke. If the ECM could not pickup the crank trigger, the engine would not even run because it has no distributor!

 

I had a talk with the owner of the dealership and asked him to have the shop re-flash the ECM with all the latest updates from GM. He did. I will try the truck again and see what's going on.

 

One of the other issues I had was the plastic ring that encases the rear window has broken (shrunk) in two spots. This lets in water when I wash the truck. The rest of the water leaks in through the gasket at the base of the mid-gate and soaks the carpet. He (Service mgr) says that they will have to remove the midgate when the new window comes in anyways so he will wait until then to fix the mid-gate leak. Evidently the new window requires a new type of seal on the mid-gate.

 

BTW - losing a drag race to an Isuzu Trooper when you are driving (at the time) Chevrolet's most powerful truck, really SUX!!!

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