So Im suddenly getting this heavy defuel every shift, what is the cause for such a thing to just pop up out of nowhere?
Heavy defuel every shift suddenly
- Thread starter turbojamie
- Start date
Fresh fuel and spin on filter sitting on my desk, both AC delco will go on tonight and repost afterwards.
Filters changed lots of black almost like grease it was so fine powder on the trans magnet. Felt the same coming home from my hoist tonight maybe it needs some learn time. Will repost back.
Relearn will not help. Check for hidden codes. If the TCM detects a trans problem it will subtley pull back fuel and timing. Switch to a different tune and see what happens.
Will do, cannot scan the A50 with what I have going to have to run to the dealer and see what they can pull for me. Pulling back power makes it shift properly, ps called ya at the shop mike, must have been at disney land lol.
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What is classed as excessive defuel? Should you be able to noticeably feel the car (and hear it) slow down between gear changes or should it be more smooth and not noticeable?
Smooth w/ maybe a slight feeling of the power dropping and coming back is what I've always thought was right. Smooth is definitely the goal. If it shifts nice and smooth your probably real close to where you want to be either way
Excessive from what I understand will literally throw you forward in your seat because it cuts power so bad/abruptly, then grabs and slams the power back on.. not smooth
Excessive from what I understand will literally throw you forward in your seat because it cuts power so bad/abruptly, then grabs and slams the power back on.. not smooth
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On my 425 tune (top tune) it does it quite noticeably, it is still smooth though but definitely slows the vehicle down compared to if it didn't do it at all. I don't think its anything to worry about just noticeable that's all, i've never been in another duramax/allison powered vehicle so it's just different for me.
Mine went from smooth to abrupt so that is why I question it. New filters on new day lets see what happens.
Not really an update but an observation towed my 26' enclosed trailer with 4 sleds in it last night to the cottage (2 hour drive) Truck works 100% in tow haul mode fyi.
New filters last week both fuel and trans. Guess I jixed myself back to crappy pull and shifting tonight on the way home...