TVS Coyote A6 Shifting Problem...

[mikengail]

It's the 2012 Vert with a fairly tame 91 octane tune that was just bumped up to an 82mm pulley from an 85mm. Problem is that during WOT pulls, the engine starts to cut out and stumble at the end of the rpm range for the previous gear and will not up-shift, unless I let off the gas a little.

Very recent problem. I had put 10k trouble free miles on the TVS with the 85 pulley and this issue had already started just prior to the pulley upgrade. I went ahead with the pulley change, because I already had it scheduled.

My tuner sent me a tune lowering the shift points and it still happens, only at the new slightly lower rpm level of the adjusted shift point. For instance, with the 3-4 shift in the previous tune, it was happening just under 7500rpm. With the new tune, it still happens but at around 6800rpm. Nannies on or off makes no difference.

Maybe not tune related? Hardware issue, perhaps? Transmission solenoid? I'm open to suggestions, before I end up taking it to my Ford dealer for a diagnosis. Engine and transmission perform completely normal under all other conditions other than WOT. Thanks in advance...

 

[me32]

What does your tuner think it might be since its still doing it with the tune update? If the only think you changed was a pulley then maybe its tune related. Also have you data logged to see if your running out of fuel with the added boost.

 

[4VFTW]

have you done any datalogging?

 

[mikengail]

Next step is to data-log. Hard to find a safe place. Monday may be the soonest.

Just to clarify, this was happening before the pulley upgrade as well. Also, since there was no change in behavior with the newest modified tune for earlier shifts and the fact that it was fine for over 10k miles, makes me a little more suspicious of a hardware issue. Anyway, more testing to follow with data-logging. I'll update then.

I was just shooting in the dark, in case some A6 person ever had a similar problem. Thanks...

 

[Scott8583]

It's probably torque management issues... I had the same thing as I made more power... Have your tuner reduce the % of torque management for each gear. There's also clutch fluid fill or something like that if I remember right...
Does it just stumble until it shifts at the top of each gear?

 

[mikengail]

Scott, it's not the stumbling, after a shift. That, for me, only happens with the the nannies engaged. I think I may have happened onto a solution from a Facebook group that my tuner frequents.

Just as a general disclaimer, this is not any vendor's fault and I'm not trying to start any vendor bashing. I know nobody has hinted at that, but I just wanted to get that out there. All the vendors I use, particularly my TVS vendor have been outstanding for me.

My particular problem may very likely be spark plug related. What I'm experiencing is being called "a blowout" by some others more knowledgeable.

As I have come to understand it, blown Coyotes are recommended to have one step colder plugs and with a narrower gap of .032" or closer, even as close as .026" depending on boost level. Not required for very low boost, but highly recommended and definitely required for high boost.

My car has 53k miles, of which 10k have been blown. Normal plug gap deterioration combined with the increase of 2 more pounds of boost has probably led to my experiencing this consistent blowout situation.

I've ordered some NGK 6510's and will gap them at .032". I'll let you all know how it goes. Thanks for the suggestion, Scott...

 

[Blazer707@TBR]

That could very well be the problem. Contact your tuner and ask what he wants the plugs gapped, some like .32 and some like .28.

 

[mikengail]

Will do, Blazer, after the weekend. Thanks...

 

[Scott8583]

Ok, sounds like it could be plugs... The 85mm to 82mm was probably more like 1/2# of boost, not 2. I would of thought your kit would have came with colder plugs.
Just to clarify, torque management kills power at or just before the shift to save the trans. That's what mine was doing.

I hope you get it figured out...

 

[mikengail]

Yeah, Scott, I'm familiar with A6 torque management. Before, I installed the TVS kit, I had a custom tune from another well known vendor and his first version was trying to take it easy on the trans and keep me straight on the road between shifts. I asked him to take it off and it was no problem plus a lot more fun. That vendor is a good guy too and, like Justin, really provides excellent customer service.

As for the boost increase, I haven't measured it. Sure feels noticeably stronger, especially in the mid-range. Actually feels a little stronger than my wife's Trinity now. Very cool.

After doing some homework that I should have done when the TVS was originally installed, I'm feeling a little foolish about the plugs. I used to know all about the relationship among combustion pressures, combustion temps and spark plug heat ranges when I was a kid building my own engines. I've become old, lazy and forgetful with respect to my resurrected muscle car hobby...

 

[mikengail]

Well, no joy. The plugs haven't solved it. Time to datalog. Easiest to tell during the 3-4 shift, but difficult to always find a safe place and time for 120mph runs...

 

[BlueSmokem5.0]

Data logging is your best friend, familiarize yourself with it and it will make it a lot easier for you tuner to diagnosis and fix the problem. Chris Holmes has been awesome tuner for me helping me to understand what to look at so I can protect my investment!!!

 

[Scott8583]

Look at your data logs for actual throttle angle & reduced timing at the shift... That's the torque management.

 

[mikengail]

Roger that, Scott. Weather hasn't been cooperating. Hopefully, tomorrow or Monday...

 

[mikengail]

Trying to close this out. Looks like, after several tune adjustments, the WOT upshift problem may be solved. Weather is not cooperating all that much lately. Latest tune revision was only tested for a single WOT 3-4 upshift run. No problems at all that one time. Will eventually try all upshift scenarios and datalog to validate. My tuner said it was some shift firmness and "drive by wire" stuff, whatever the latter means.

Interesting side note is that during the next to last revision, I tried with both stock tires and DR's. With DR's the problem didn't appear, but with the stock 235's, it was still a slight problem. Seemed like the car was still trying to override the driver commands with minor tire slippage and all the nannies off. Even at speeds as high as 80+, I guess the tires were still slipping a little when shifting. I would oftentimes hear and/or feel slippage at 2-3 shift, but not at 3-4 where the problem was the worst. Go figure.

Anyway, looking forward to March when the local track opens to see how much difference the 82mm pulley and the DR's make. Low 11's to high 10's perhaps? Thanks for all the feedback from everyone.

 

[Scott8583]

Good to hear your making progress... When my car hooks the shifts are consistent, if it spins on the launch it throws the shifting out of wack (to some degree). That's probably why it was worse on the stock tires.
82mm = low 11's to high 10's for sure! Good luck next season. Winter sucks up here in the north, I'm dying for spring to come & the tracks to re open! Lol!

 

[mikengail]

Thanks, Scott. I'll keep you posted. Took my installer on a test run with the DR's and surprised him. He said it felt like a 10 second car to him. We shall see...