Shifting straight up 1-2-3-4 at WOT at less than 30 mph?

[Paul Powell]

Okay,
Most of you probably know what is causing this but a 1999 5.3L Truck.

Just a Cam and springs, Long Tubes, Ported Heads, CAI and 3000 stall converter.

Should be a simple tune. Dyno fine. Made 278 rwhp (I didn't do the engine)


But when you drive it on the street and go WOT form a dead stand still or WOT at low speed it goes 1-2-3-4 gear changes and obviously goes no where (and would kill the trans if we leave it that way)


Tune and logs are attached.


By the way it does fine if you pull it to D1 and manually shift to D2 then D3 but goes directly to 4th. But sometimes if you go WOT it acts totally fine?????


Anyone seen this?


1500 with cam WOT Shift Issue.hpt1500-6 wot upshifts issue.hpl1500-7 wot upshifts issue.hpl1500-8 wot upshifts issue.hpl

[ryan_axberg]

I see your full throttle shift speed for 2-1 and 3-2 is less than your 1-2 and 2-3, you always want the 2-1 lower than the 1-2. Also the full throttle shift rpm is 5200, if you have any sort of cam in there I would put it atleast at like 6 grand.

[5FDP]

Side note, it's probably way out of fuel too. Them tiny 21-22lb/hr injectors are so tiny, log injector pulse width avg and watch your duty cycle peg past 100%.

[Paul Powell]

So the cal is the factory cal on the transmission. As far as upshifts and down shifts points, That is what was in the ECM (stock) Still this thing is going straight to 1-2-3-4 at less than 25 mph????
As far as the Injectors, I will check on the DC. But it was as rich as 10.8 at 6200 rpm on the dyno. I leaned it out a fair amount to get it to 12.8 A/F.

Also like I said sometimes when you go WOT is does everything fine. You can see in the log both happening.

[Russ K]

https://forum.hptuners.com/showthrea...ht=curse+P0121

Russ Kemp

[Paul Powell]

Bingo! we have a winner!

Thanks Russ K