Hesitation in boost and high rpm

polskifacet

New member
Same issue as the cold weather KR. Seems like as soon as the temperature gets around 30 and winter blend kicks in, this comes up. Tuned back down to 87 until gas gets better and temp goes up so I don't blow another motor....
 
Knock sensor wires?  That was one of the causes of the false KR, so securing them might help here.
 
Have any data logs?

I dont think winter blend is as much of a problem as people think...maybe if you are on the ragged edge but I doubt your lms tune is
 
not setup for any decent logging. I just put the 87 tune i have from lms and it doesn't happen any more. Also see my ltf trims are a good amount higher +13 to +15.
 
AJP turbo said:
Have any data logs?

I dont think winter blend is as much of a problem as people think...maybe if you are on the ragged edge but I doubt your lms tune is

I agree.

Listen -- I've had on and off problems with my LMS tune since I bought it two and a half years ago. I think the tunes are excellent -- when it's warm and you have good traction. I honestly think the problem is one of these things:

#1 bent rims, cold tires, low air, or unbalanced tires setting off the traction control. What does your tire pressure look like? When was the last time you had your tires balanced? How bad was the wobble? Mine was pretty bad.

#2 Steering angle sensor issues - Since I had the car, my car would bust out a C1B00 DTC every once in a while. While I highly DOUBT that this is the case, its still different than a "healthy car". Perhaps its messing with the torque vectoring exposing a bug in the ECU under higher boost / RPM?

#3 The tune. I've had popping / hesitation on summer gas, winter gas, small blend of E85 gas, with octane booster, and with 89 / 91 / 93 octane gas. I had problems with the 91 2bar / 91 3 bar / 93 2 bar and 93 3 bar tunes with this hesitation. Version 8 - whatever it is now.  It's fine while stock, just the tune is amplifying something.

When you think of what's changed -- you have to ask ATPturbo and LMS to be certain, but I think its only torque based and transmission line pressure (shift points too). Something just isn't happy with the car.

I am not bashing LMS. I think they provide excellent customer service. I also think my video blog pissed a few people off and they somewhat gave up on finding the root cause of my vehicle. That's neither here nor there, after I changed my front tires to the back, I've had very little problems with the car; so I'm just blaming it on that..

#4 I know there are a few tuning companies out there that have good results. Sabtaj has the unleashed tune, and he's had none of the problems I've had. Granted he runs different tires, rims, and is doing the whole E85 / meth / crazy tune route. He just showed me a video of him going head to head with a hellcat -- close race too :)

Good luck -- I hope I've helped you.

 
Has be gas/tune related. I've done a lot of troubleshooting on the last engine and the only thing that fixed it in the winter was buying race gas.
 
Hmm. Maybe MMO or TC-W3 or another Upper Cylinder Lubricant might work as well, working it from the fueling side.
 
polskifacet said:
Has be gas/tune related. I've done a lot of troubleshooting on the last engine and the only thing that fixed it in the winter was buying race gas.

Really dont want to be blending E ....and if you weren't then its simply the tune, winter blend fuel isnt a problem maybe a problem in the tune is exaggerated in the cold....people want to blame KR on the winter fuel but i can tell you the iat compensations for cold temps are aggressive and maybe add too much spark which will have to be pulled back out as KR
 
Only use Shell 93 so my opinion is also that its a tune issue. Probably not worth it for LMS to fix it for the couple of us having these issues.
 
Would be interesting to see if people that have implemented the AJP tune/mod are experiencing this also.  I know people running Unleashed tunes do so it's definitely not an LME vs Unleashed type thing.
 
I haven't done major driving/dogging on my car in the cold, but can say I have noticed no hesitations/stutters/issues with my AJP tune. I noticed no issue on the pump gas tune a while back, and still have no issue running an E20 tune with the mods in my sig.

In fact, the last 5 revisions or so worth of logs I have sent to Brad were with ambient between 30 and 45 degrees F. I see, at most, 2.5 degrees of KR after just refilling the car -if the mix is a bit off- OR after loading a new revisions when the learning is occuring. Once the trims are all set, max KR is 1.5 degrees or so.

 
polskifacet said:
Has be gas/tune related. I've done a lot of troubleshooting on the last engine and the only thing that fixed it in the winter was buying race gas.

Have you checked your tire pressure lately? Cold weather will lower your tire pressure. I know you know this, but it doesn't HAVE to be the TUNE. I ran my head against the same wall -- ask anyone here -- I'm just trying to save you a headache.

My popping & hesitation, went away with my LMS tune when I moved my bent front rim to the rear. In fact, I didn't even know it was bent or had issues. I didn't feel it in the steering, nor on the car while driving. But put it on the wheel balance and holy hell it shakes.

I'm assuming you have a non-PP -- which I'm finding my non-PP is WAAAAAY more sensitive to wheel slip.  Even when you turn traction control off, it still goes retarded in certain conditions. That feeling of when your wheels are slipping with ETC on and traction control activates, is the same hesitation you're feeling at high RPM.

I've driven my SHO for about 65k on the LMS tune. All I can tell you is from my extensive and exhaustive posts on this issue-- and fighting with LMS... and fighting with other forum members.
 
I am familiar with it acting weird with traction issues but I know that is not the issue here. Happens on both sets of wheels which I just swapped for my winter set. Happens at 30 mph but more noticeable at higher speeds as the gear holds longer around the top of the rpm range, it feels like it just looses power in a series of spots. It is usually intermittent and will happen once then not repeat itself until I am not trying to reproduce it. I also have high KR (6) right now but not when in boost usually between 0 and 5 points of vacuum. It ran fine until I noticed LOR started dropping, at (-5) now and as I have said, close to freezing temperatures. Non such issues occur on the 87 3bar tune I have from LMS. I also haven't gained the courage to run the 93 octane tune so this was happening on the 91 octane tune while running Shell Nitro+ 93.
 
Shouldn't happen on the 91 tune for sure with Nitro.  Any possibility this is bad fuel, or has this happened over multiple tanks?
 
ive wrote a post about this as well feels like my car is miss only at WOT. Ive spent quite a bit on replacing things thinking it was mechanical because that is what LMS said. A lot happen in a week I tried some VP racing fuel, weather got cold and had a custom exhaust done. car ran decent when it was warm. iit Had middle section of exhaust done just not the axle back.
 
14SHOCAR said:
I think you clearly made your point on your above mentioned post and quite frankly don't see the need to bring up these past discussions unless you truly enjoy stirring the pot. Z
 
I think you clearly made your point on your above mentioned post and quite frankly don't see the need to bring up these past discussions unless you truly enjoy stirring the pot. Z

No pot stirring, I just wish I had this info to read a year ago when I first noticed. I understand that a box tune is never perfect but I also would like to know that this is happening to more than 1 car so I can just run an 87 tune until spring without loosing my mind that my car is F'ed up lol.
 
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