decrease power from SCT

I got the sct from roe, 91-93 and 94 tune

I did 4 times(93) a 1/4 mile run against a 2006 QC(cai and magnaflow exhaust)
killed him 4 times easy.
One time i gave him a head start and he still didn´t beat me.:rock:
I run hi 12,low 13 he runs low 14.

Alex
 
msdnga said:
If your AFR is lean as they are from the factory, you will make more power peak on a dyno, but not below the curve. Post up the stock curve with AFR and the 93 Curve for us to check out. Peak power won't win a race.

I thought these trucks were really rich in stock form??:dontknow:
 
Marc T said:
I thought these trucks were really rich in stock form??:dontknow:

If they were very rich from the factory the cat's would burn up.:p
 
supercar1of1 said:
If they were very rich from the factory the cat's would burn up.:p

they do quite often in the genII engines...usually end up puking out the guts
 
I have had the same problem with two different tuners. I then bought a Innovate LM-1 with the RPM Converter. It uses the Bosch 5 wire wideband O2 sensor. In stock tune the truck will turn the tires over better than any of the 93 tunes I have tried. The 93 tunes are better when passing traphic when it kicks down. I can hear how fat the truck is. This last time for data a did two runs from 40 MPH, no kick down, up to 5250 RPM. Tried the adjusted tune and it was no better than the first.

The truck also acted better with my Stage 2 Flash from B&G.

AFR at idle and cruising was always around 14.3. When WOT it drop down to 12.9 - 13.1. My SCT shows no codes. I even put in a new IAT sensor.

I am not blaming anyone for my trouble but I can't figure out the problem. Very frustrating!:dontknow:

IT IS NOT ANY VENDOR'S TUNE FAULT! It is my truck. Something is just not acting right on my truck?????


Any advice appreciated.
 
How long does it stay at 12.9-13.1 when WOT? Is this happening when it down shifts when you go WOT?
 
It was happening evrytime WOT. Did not matter whether it was a down shift or not.

I have not checked the AFR since the latest tune i put in yesterday.
 
You may have a bad O2 sensor (or 2).....I had all kinds of trouble with A/F a while back and it turned out to be a bad sensor...:dontknow:
 
rreinicherr said:
Where can you get a stock O2 sensor?

THANKS!

Your dealer....or most any parts store...Advance, Napa, etc.......if your dealer will cooperate they can use their StarScan to check the O2 sensors....if not the sensors are 20 some bucks so not a real expensive fix........though this may not be your problem..:dontknow:
 
rreinicherr said:
I have had the same problem with two different tuners. I then bought a Innovate LM-1 with the RPM Converter. It uses the Bosch 5 wire wideband O2 sensor. In stock tune the truck will turn the tires over better than any of the 93 tunes I have tried. The 93 tunes are better when passing traphic when it kicks down. I can hear how fat the truck is. This last time for data a did two runs from 40 MPH, no kick down, up to 5250 RPM. Tried the adjusted tune and it was no better than the first.

The truck also acted better with my Stage 2 Flash from B&G.

AFR at idle and cruising was always around 14.3. When WOT it drop down to 12.9 - 13.1. My SCT shows no codes. I even put in a new IAT sensor.

I am not blaming anyone for my trouble but I can't figure out the problem. Very frustrating!:dontknow:

IT IS NOT ANY VENDOR'S TUNE FAULT! It is my truck. Something is just not acting right on my truck?????


Any advice appreciated.

Make sure you don't have a vacuum leak. I had a vacuum leak during tuning which made the engine run super rich. At idle it was at 10.0 to 1 ratio. At first we thought it was a bad 02 sensor but it turned out to be a vacuum leak. Hope this helps.

Brad
 
THANKS!

Wouldn't a bad O2 sensor trip a DTC code that would show up on the SCT Diagnostics Check?
 
well i ran the truck again today. weird results....

i will post the graph when i get it scanned over. max results were 432/479. not too bad for just 3 mods.
 

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so the weird part is ... u can see on 5-30 that i had the decrease. then today when i test the same thing just with wideband, the max numbers were much better as well as the tunes. that is only 500 miles later. why would the tuner all the sudden give some decent numbers. are these the results i should expect?? oh and yes the dumbasses didnt do it in rpm on the new runs. no fucking clue why they did that but i think its good enough.

but again why would i have a 30hp increase all the sudden. thats alot. 5-10 i can see but 30....?
 
coloradokid said:
so the weird part is ... u can see on 5-30 that i had the decrease. then today when i test the same thing just with wideband, the max numbers were much better as well as the tunes. that is only 500 miles later. why would the tuner all the sudden give some decent numbers. are these the results i should expect?? oh and yes the dumbasses didnt do it in rpm on the new runs. no fucking clue why they did that but i think its good enough.

but again why would i have a 30hp increase all the sudden. thats alot. 5-10 i can see but 30....?

Takes about 500 miles for the PCM to adjust, you should get some more gains with more miles...limited, but a little more
 

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