454 has issues with hypertech tune

[1998454]

I have a 98 k2500 with a 454 and just bolt on mods. I noticed a gradual decrease in power and transmission shift firmness over time so i reloaded the hypertech tune. Truck ran great, and shifted pretty hard for about three days, then slowly the shifts smoothed out, and power seemed to fade a little. Reload program and everythings fine again. Anyone have any idea why i would have to reload it weekly to keep everything the way it should be? It is a power programmer plus. And hypertech has been zero help.

[speedracer326]

Sell that POS and get a real tune. Do a search on hypertech on here and see how many dissatisfied customers there are, it isn't worth your time to figure out why.

[Redz Z]

I am guessing that the ECM is compensating for the Hypertech tune somehow and nulling out any gains.

Do you program the ECM and then start driving immediately? If so, you may want to disconnect the battery for like 30 mins. after the programming, reconnect the battery and let the ECM relearn with the tune programmed. Maybe it won't null out the tune that way. This is just a start. See how that goes and report back. This won't be too hard to get to the bottom of.

[speedracer326]

I could have pulled that out my ass, way to speculate without any evidence. Disconnecting the battery on an OBDII does nothing. The Hyperjunk "tune" nets half the gains of a real tune but brings with it issues like this.

[1998454]

I agree, i need to get a good tune. What i don't understand is how it takes a tune, then gradually changes itself. Makes me wonder if i get someone to tune it if it will stay, and if it will, why won't this one? Don't get me wrong, it's still alot better than stock settings, even after a few weeks. I've heard alot of complaints about hypertech, but never the issue that i have. I will try unhooking the battery, can't hurt anything.

[speedracer326]

Well on the shift tables within the computer, there are commanded shift times. The PCM will alter line pressures to achieve these commanded shift times. The only time I've ever heard of a transmission learning itself softer, so to speak, is when a shift kit has been installed in the transmission. The PCM will initially shift with the same line pressures that made it shift at the commanded times with the stock "shift kit", but that pressure is no longer applicable with the shift kit so it dials it back until the desired shift times are again achieved.