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Spartan Tuned & jerking real bad

5K views 29 replies 12 participants last post by  harleysdontbitc 
#1 ·
I have been Spartan tuned now for 35k miles. For the last year now when ever I am pulling a load and accelerating between 50 - 65 mph the truck jerks real bad as if I am pumping the throttle. Once I get above 60 - 65 mph it smooths out. When ever it does it I have to get out of the throttle and ease back into real easy until I get 60 - 65 mph. It does it when I manually throttle it or even in cruise control. It does it on all tunes. Anyone else experiencing this?
 
#4 ·
My truck does the same thing towing 250 and up tunes. What makes no sense is it seems to get worse the longer you leave the tune on the truck.
 
#7 ·
I've experienced the same thing running the 250, especially when I'm running in Tow/Haul mode. The TC locks up in a lower gear (5?) around 40-45mph and if your foot bounces from hitting a bump or something, with such a sensitive pedal, the truck jerks, causing your foot to bouce again, causing the truck to jerk, causing your foot to bounce, etc.... The rhythm is just right to make the truck do silly things. Its not hard to do on purpose either. Best thing to do when it happens, is just take your foot totally off the long skinny pedal on the right.

Not sure if this is the problem the OP is talking about, but it sounds like it to me.

For me, it happens without a trailer too. As I said, especially when in tow/haul mode. TC locked in the gear before OD.
 
#8 ·
It does it with the cruise control accelerating as well. I can be accelerating very smoothly with cruise control or manually and once I get between the speeds ranging from 55 - 65 mph it starts jerking very badly. Once you get above 60 - 65 it stops. Usually I have to get off the throttle or kick out the cruise and it usually takes me 2 -3 tries to get above 65 mph without it jerking real bad.
 
#11 ·
Stuff like this....I just don't understand. I have never broken anything in a transmission, stock or SunCoast. I drag race my truck and use my truck for tune testing. Spartan tuned for 70,000 miles....
 
#15 ·
I have had this happen to me as well, Mostly when I was towing using the regular 210 tune.
And mostly when the cruze was on, I know it was not filters cause the first time it happened I had only about 500 miles on new filters. I work around it and make sure to kick out the cruze as soon as I feel it coming on. That said what you think needs to be done to cure the problem?
Low Pressure fuel? Need a FASS/Airdog?:dunno:
Throttle tip-in? I am not smart enough to even guess what that is:doh:
Sometimes it is the tune? I am a Spartan fan and flag waver, So feel free to Email me tunes if that’s what it takes:woot::nod:
 
#17 ·
Hopefully the upcomming update will have the problem fixed.

i wonder also if a fass/airdog will help the problem if its the low pressure fuel system? :dunno:
I only see the bucking on the 310 tune on the highway. I don't experience it with the lower tunes (210-300). I have an Air Dog II on my truck, but I am not saying that is the fix for it.
 
#16 ·
i wonder also if a fass/airdog will help the problem if its the low pressure fuel system? :dunno:
 
#21 ·
My 05 6.0 did something similar to this last weekend. I was pulling a 21' camper with SCT IDP xtreme street tune. I usually pull with a tow tune , but didn't feel like swapping over to pull only a few miles.

Anyway, as I was pulling up a long grade in OD and the boost starts rising like normal to power up the hill and keep from downshifting and as it started picking up power the truck bucked several times so i put it in Tow/haul, it downshifted and everything was cool.

Now I assume this was the transmission slipping in OD, as the truck has orig. trans with 167k and has it will shift a little funny every now and then, and occasionally slips on a hard acceleration.

Not sure if this helps, but I figured I'd share.
 
#25 ·
Im curious to what you find, Im H&S tuned for only 1000 miles so far. It feels very tappy with anything below 30mph, but I think its more the higher HP tune, getting a steady foot, and the truck basically asking me to stomp on it and go faster like it wants.:thumb:
 
#29 ·
Well I won't argue with you jeff or bad mouth Spartan because in general I'm happy with the product and understand things take time. Was just pointing out that the entire update debacle and customer expectation management is something that bugs me, end of
story.
 
#30 ·
The thing that makes me nervous is updating the DD and then reinstalling things.
I have 100% confidence in Matt’s tunes and I am looking forward to being able to get the update
(What tunes are being updated??) I know when I do the update I am going to put the truck back to stock, before I do anything with the DD. I have read too many posts of guys that have messed up the update somehow and then the truck is DOA in the driveway. I think I might just make sure that it is regular office hrs at Spartan as well, Just in case I need to call someone.
 
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