16 silverado l83 BTR stage II cam... Idle dipping hard when coming to a stop..

[johnwood]

so I have a Cammed l83, nothing serious done to it, but I am having issue with the truck dipping idle hard when coming to a stop.. the truck runs well otherwise but I'm tired of the rpm dip.. goes from 850 down to 400 sometimes less very quickly and right back up. hppens in the blink of an eye, but it isnt right and it is slamming my brand-new transmission when it jumps back up... If anyone could help me out with some advice on where to look or how to compare log to tune file and make the changes needed... Id like to have it fixed as ive already paid for it, but i will make sure he doesnt touch another one of my vehicles or anyone I know... He even missed a major misfire in the beginning... the truck is perfect, not one thing wrong with it...

[GHuggins]

Post an idle log. Cold start to hot idle. Blip throttle in park couple of times and then t
Put into gear and repeat throttle blips.

[johnwood]

ok i will have to get you that in the morning as ive driven the truck all day.. it will not replicate the issue when its colder 190.. It will only do it when hot. when its cold it drives perfectly. when its up in temp, or I just get off a freeway drive as soon as i go to stop it dips hard and jumps back up slamming the transmission. I think mastuned doesnt know how to fix it because he is now ignoring me...


hhh.hpl

[johnwood]

121212.hpl

[johnwood]

in the 121212 log the issues occurs between 1:51:11.682-1:51:13.092.. I believe it happened a few times in this log but it happens in the blink of an eye. its hard to see while playing the tune..

I am currently letting the truck cool and will get the log you would like to see.. I appreciate you taking time out of your day to give me a hand... I should've looked more thoroughly for a tuner.. Its been nothing but a hassle with the initial tuner.

[GHuggins]

For starters the MAF and density tables need to be dialed in. Fueling and torque go from +10 on trims and +18lbft on torque while colder and then to 0ish on trims and -35lbft on torque all at the same idle rpm from start of log to end and that's going from a warm engine to a hot engine. This is why I tell people the density table is probably the single most important table in one of these calibrations and the most time consuming of all the tables to dial in. Your torque model and idle controls will also need to be massaged after getting the density, MAF and VE all back right. The negative torque at idle then having that sudden punch of positive torque is what you're feeling. Got to watch out with this cause it can cause reverse clutch slippage too. Been there done that. Needs to hover around 0 to +20ish at hot idle to keep things happy. At least that's what I'm seeing in the log...

[johnwood]

Alright, I sent you a message. its beyond me at this point.. Im debating setting it on fire, jk.. I appreciate the feedback... I will mess with it until its right or blown up idk.. JK I will get it taken care of one way or another..

[Camaro6]

Post the tune. Either your base airflow is low, you jacked with tq tables, not enough control on the idle tq table, or the tune is just that far off. Stock converter or changed it out? Is the trans tuned as well or stock?

I have stg3 btr cams in these trucks with stock converters. They idle and run very well.

[johnwood]

The transmission is built. Billet converter etc.. The trans was supposed to be tuned.. I paid to have a complete tune, but at this point it may be screwed up as well. I cannot fix it because idk how.. if i did, I wouldnt be as aggravated as I am with initial tuner because I wouldnt have used him. Ive been lied to and ignored. Im going to get with G huggins and let him tune it soon.. I just have to wait as ive already paid for this lousy work..

[Camaro6]

Built trans with converter definitely needs a trans tune. It could be pulling the rpm down by too much pressure on the converter side of things or your idle parameters. I need to see the tune to help you on this issue.

[johnwood]

The whole truck was tuned by a guaranteed tuner.. Hell I have 2 guys arguing now that he is the greatest out there after I called him out on here, lmao... I will post the tune file.. Thank you for the response..

I dont know if thats the case tho.. it will not replicate the issue any cooler than 190 degrees ect.. If it was trans related, I would think it would cause this issue every time I stopped..

[johnwood]

we shall see tune 5.hpt

Here is the file. I think it may be torque related.. The truck will idle fine when coming to a stop until its warmed up, then the idle starts to drop hard when coming to a stop.. When I am almost stopped the idle drops down, sometimes to 200rpm then jumps up instantly back to setpoint slamming the truck.. The virtual torque numbers are all over the place. It doesnt match the stock intervals.. stock had maybe a 7-10 point increase throughout, the new tune has 30+ point increases from negative to positive and vice-versa. I dont really know what has happened to it. it didnt do this before it was "professionally" tuned..

[Alvin]

Heads up..

I would definitely disable Virtual flex fuel on a application like this. The stoich table has been flatlined so fueling changes shouldn't happen but I wouldn't trust that a torque adder or something like that isn't in play.

[johnwood]

Heads up..

I would definitely disable Virtual flex fuel on a application like this. The stoich table has been flatlined so fueling changes shouldn't happen but I wouldn't trust that a torque adder or something like that isn't in play.

thank you. Where do you find this?

[johnwood]

What does the virtual flex fuel do exactly? And where do i find it lol.. im not very experienced with these operating systems.. thank you again for the advice..

Is it flex fuel drop down under fuel>flex fuel-general?

This was disabled in the stock tune, I noticed it when i pulled up a compare file.. Tuner was really lost on this one..

[mhi734]

did you solved your problem or not ?