Loss of power with programmer

Procelll · Post by **Procelll** » Sun Sep 28, 2008 1:21 pm

I finally got the time to put my truck on the dyno yesterday. I ran a run without the programmer and a run with the diablo sport tune on it. The truck is a 2003 Chevy Silverado. The Dyno showed a loss of 8 Max Torque and a loss of 20 hp what could have cause that to happen? It had 93 octane in the gas tank.

CANUCKPREDATOR · Post by **CANUCKPREDATOR** » Sun Sep 28, 2008 5:02 pm

Have you done this?

http://www.diablosport.com/index.php?na ... opic&t=917

Any problem with the truck? No codes?

Procelll · Post by **Procelll** » Tue Sep 30, 2008 12:34 am

Truck shows no codes. Runs great it feels like its running better with the programmer on it but the dyno shows that i've lost power.

CANUCKPREDATOR · Post by **CANUCKPREDATOR** » Tue Sep 30, 2008 1:32 am

have you followed the instructions in the link? That will help.

Procelll · Post by **Procelll** » Tue Sep 30, 2008 1:49 pm

I havent had a chance yet I'll probably have to wait to the weekend and then ill post up on here.

Post by **mikel** » Tue Sep 30, 2008 1:59 pm

Sounds like bad gas may have beeb responsible for the power loss as a result of KR.

Procelll · Post by **Procelll** » Wed Oct 01, 2008 11:54 pm

i dont think its bad gas cause it still runs great.

concoursd · Post by **concoursd** » Thu Oct 02, 2008 1:24 am

when did you do the baseline run? Was it that day or prior? What was the A/F ratio like for each run? You should log for KR with your predator while you are doing a dyno run. It is possible that you triggered COT on your predator runs which means that the truck richens up the a/f ratio to protect the catalytic converters and exhaust valves and consequently reduces power significantly. That is why an A/F ratio plot will reveal that. KR can also kill performance if any pinging is detected and timing is pulled.

Post by **mikel** » Thu Oct 02, 2008 11:09 am

Yup.
I say there is KR up top causing the loss of power, but the improved throttle response and timing down low are making it feel better on the street...
Figure out the KR and it should wake up.

Procelll · Post by **Procelll** » Tue Oct 07, 2008 11:22 pm

what is KR?

Coolcrash · Post by **Coolcrash** » Tue Oct 07, 2008 11:33 pm

Knock Retard (hereafter referred to as KR) is the response from the PCM to cylinder detonation. KR is the measure of the number of degrees of overall ignition timing advance that must be removed from the engine to prevent detonation from continuing, thus protecting the engine from damage

Procelll · Post by **Procelll** » Thu Oct 09, 2008 12:05 am

oh ok thanks