Engine/Transmission (1998.5 - 2002) stumble with now injectors

[dknoch]

I purchased new Mach 2 injectors and installed them yesterday. When I took the truck for a test drive, it drove great except for at about 3/4 throttle in 6th gear with boost at about 20-25 psi the truck would almost feel like it had a slight miss. At wide open throttle it would go away and take off nice and smooth. The truck is an ETH so I don't know if the timing of the ETH with 30 deg temps and the added timing of the Smarty caused this? It used to do that in the winter with an Edge EZ with RV 275 injecotrs but I put a winter front on the truck and it went away. This morning, I put the winter front on the truck and adjusted the Smarty to timing 2 instead of 3 in the REVO software and it still had this problem, just not as bad. After playing around, I tuned the timing to Stock on the Smarty and this seems to have cured the problem. I guess what I really want to know is if this could be a simptom of something else. Could a valve need adjusting, would the Mach 2's advance the timing more than the RV 275's and that be enough to set this off? Could this problem have been there for ever and the bigger injectors made it more noticable? The only codes I got from the Smarty were the usual 0602 and the companion code. No codes at all now on software 4 (no timing) everything set to defult. Should I just not worry about it and leave it like this for the winter or could there be something else wrong with the truck?

Thanks,

Dan Knoch

 

[darkhorse]

It doesn't exactly sound like air in the lines. I'm running 3. 8's with my Smarty set all the way up on an ETH without the stumble you describe so I question if it's timing. The bigger injectors will magnify an issue that isn't noticeable with smaller nozzles.

 

[dknoch]

Yeah, I don't know. It seems to be less of an issue without the timing. I think if something got mess up during the install, it would be noticeable all the time. Could an injector be off by a little bit? Still no codes at all with the Smarty on 4.