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Im Scared

3K views 36 replies 7 participants last post by  06F-250-6.0 
#1 ·
I just decided to run my truck through and i looked down and the tach was at about 4600 rpm! it wouldnt shift out of first thats y i looked down! WTF Is Going On!! I thought the SCT wouldnt let it go tha far! Its gonna freaking blow up if it lets it get that high! I dont even want to get on it now! It blew out some white smoke and acted funny for about a mile or 2 after it happened...Anybody know why this happened and will it do it again if i try to run it through again...
 
#29 ·
that was my mistake...their email is correct..
 
#31 ·
The fuel rev limiter in our Xtreme tune is set at 4200 rpms. The factory fuel limiter and crank limiter is at 4000 and 4500 respectively. Since there isn't any spark to cut, the truck defuels. Even after it defuels, it will continue burning what fuel is left. Before you hit the rev limiter, the truck is constantly defueling so cylinder pressures would be lower at the rev limiter than in the mid rpms where the power peaks.

Hitting the rev limiter won't hurt your truck. That's what it's there for. When we dyno our trucks, they pull right to the limiter. You don't want to sit and hold the rev limiter all day, but it's there to limit the revs. It sounds like your trans went into limp mode. Spinning tires during shifts will cause this to happen.
 
#32 ·
ok...ill try it again tomm and if it happens again ill post it up here..Thanks for the info...
 
#34 ·
...or better yet you could contact me and I'll help you diagnose why the truck isn't shifting. It should make all the gear changes seamlessly, with the exception of spinning tires too fast for it to keep up. If you have a constant problem, you may have a sticking selenoid. A little dirt on the selenoid can wreak havoc. Most of the time it clears up or I can quicken the shifts to help out some. The 3-5 shift is the most common for this issue.
 
#35 ·
Thanks for getting us straight Eric! I've seen mine do some stupid things with regards to shifting, but it has always been due to erratic driver input!
 
#36 ·
ok sounds good...it was 1-2 shift...
 
#37 ·
Everything went ok today...It seemed that the shifts were rougher than normal but its getting better...
 
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