Paging Allen or anyone with HPT experience, glitch on the 2/3 shift at dragstrip

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11-08-2009, 05:08 AM
Blown06

Paging Allen or anyone with HPT experience, glitch on the 2/3 shift at dragstrip

This has happened to me twice now on different nights. I use the box to do stand alone logging.
Right before the 2/3 shift the motor acts like it hits the rev limiter and the tranny wont shift. However the rpms are nowwhere near the rev limit. It almost seems as if the ignition just shuts off. As soon as I let off the throttle everything goes back to normal. I can get back in the throttle and its like nothing ever happened. This has happened twice with 2 different tunes so I don't think its related to a specific tune. Also, I think it might be HPT related cause the err light on the box blinks till I clear it. Commanded shift rpm is 6900, rev limit is set to 7500, log stops recording at 6600.
Does anyone know what this could be???
11-08-2009, 12:06 PM
trx2stroke4life39

What is your shift mph set at? if it is to high it will act like it is hitting the rev limiter.
11-08-2009, 08:40 PM
farmtruc

If the tune hasn't changed much, the mph shift points will be lower than the RPM shift point.

With your vehicle, the rev limiter should feel like the truck just stalls or doesn't accelerate, is it doing that, or is the engine popping or backfiring?
11-08-2009, 10:31 PM
Blown06

Quote:

Originally Posted by farmtruc

If the tune hasn't changed much, the mph shift points will be lower than the RPM shift point.

With your vehicle, the rev limiter should feel like the truck just stalls or doesn't accelerate, is it doing that, or is the engine popping or backfiring?

I sounds to me like it backfires, but everyone in the stands was like "why did you let out of it". It feels just like the rev limiter, but the truck doesn't do anything till I let off the throttle. Also, the first time it did it the mph was higher than the rpm shift points, this time the rpm was higher than the mph shift points.

One thing that I just thought of, I've heard of guys (Flaco for sure) who have had the electronic throttles slam shut because of so much airflow, could this be the problem?
11-08-2009, 10:37 PM
GasGuzzler

Sounds like a simple loose connection although I wonder why you have all those parameters set so high.
11-09-2009, 02:19 AM
Blown06

Quote:

Originally Posted by GasGuzzler

Sounds like a simple loose connection although I wonder why you have all those parameters set so high.

Because thats where it makes power.