SP542 Thread

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Jeff-Ohio

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do you have any sort of tune?

I've come to notice that ANY modification to the PCM ( even to a degree a pedal commander) makes the torque management system pretty quirky. I have a feeling that there are some nannies coded into the module that do not react well to any changes whatsoever in the engine mapping.

I think you are right. I do have a tune. The problem exists without the tune, but it is definitely magnified with the tune.
 

zombiekiller

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I think you are right. I do have a tune. The problem exists without the tune, but it is definitely magnified with the tune.

there is a reason why whipple and livernois shied away from messing with the transmission tuning holistically.

With all of the engine/trans/torque/iwe/etc issues abound, I have to believe that reason is a pretty good one.

then again, that is my $.02.
 

Jeff-Ohio

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there is a reason why whipple and livernois shied away from messing with the transmission tuning holistically.

With all of the engine/trans/torque/iwe/etc issues abound, I have to believe that reason is a pretty good one.

then again, that is my $.02.

Now that I see where you are going, I apologize for leaving this piece of information out. The tune that I am running is with the stock transmission calibration. My tune company offers tunes with transmission calibrations, but the one that I use does not do any transmission alterations.
 
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Jeff-Ohio

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That RPM range is in line with peak cylinder pressures in turbo motors and can be an indication of knock, pinging, detonation. That's what I experienced in years of running a 944 turbo race car

Assuming everything you said is true, that is what I was hoping the installation of a cooler plug (the 542) would help rectify, but it didn't. Should I go to an even cooler plug than the 542, or is it possibly something else? I really like my truck, but getting all of the querks worked out has been somewhat expensive and time consuming.
 

eclou

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Assuming everything you said is true, that is what I was hoping the installation of a cooler plug (the 542) would help rectify, but it didn't. Should I go to an even cooler plug than the 542, or is it possibly something else? I really like my truck, but getting all of the querks worked out has been somewhat expensive and time consuming.

I would try to find out what is wrong with the car by setting it back to stock - tune, plugs, intake or whatever. It may be anything that throws off your AFR / vacuum leak, poor fuel quality (I only try to use Shell 93), or bad spark (coil). Run a diagnostic log to see if there are any error codes pending.
 

Jeff-Ohio

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I would try to find out what is wrong with the car by setting it back to stock - tune, plugs, intake or whatever. It may be anything that throws off your AFR / vacuum leak, poor fuel quality (I only try to use Shell 93), or bad spark (coil). Run a diagnostic log to see if there are any error codes pending.

That is great advice and I fully agree, but I have gone rogue because I had my truck at the dealership more time than I had it at my house during the first six months of ownership seeking their assistance trying to fix this issue and a gas pedal vibration issue. The gas pedal vibration was finally fixed by me after endlessly testing numerous other "solutions". What ultimately worked for me with respect the gas pedal was replacing the resonator with an X-pipe that removed what my dealer called a "harmonic frequency" vibration. The X-pipe seems to balance the the pulses in the exhaust pipes and thereby gets rid of the frequency that caused the gas pedal to vibrate like a cell phone on vibrate mode.

Regarding the "stutter" under acceleration, they seem to be unable to help unless the truck is throwing codes, so I am trying everything, similar to the gas pedal situation, to fix it on my own, hence, several different types plugs, running only Shell gas with 93 octane, purchasing a tune, etc....
 
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