Prodigy Performance Turbo Driveability Issues

[2k13jk]

I have the same problem with my ripp on my 2013 2 door manual. It doesnt want to accelerate smoothly when the engine is cold or below 160 degrees on my Scan gauge. Also the highway problem your referring to when you press the pedal a hair to speed up and it dies for a second then picks up. My jk has the same issue and when it happens my air fuel gauge will go to 15.7 or more on the lean scale then quickly richen up. I believe it's the ecu trying to stay in "Eco" mode or the aftermarket map sensor is delayed trying to read positive manifold pressure beyond the factory calibrations

[UselessPickles]

My throttle mapping issue is not time-dependent, so it's not any kind of "delay". It's not "dying for a second then picking up". That sounds like a hesitation. There's no delay/confusion caused by positive boost readings. The ECU is recalibrated to account for MAP readings into the positive boost range.

Also, "eco mode" is not a mode that the ECU tries to operate in. "eco mode" is simply an indicator of whether you are currently operating the vehicle in a way that makes for good fuel economy.

My problem is that there is a wide range of throttle positions (25%-95% pedal position) in this particular situation (freeways speeds in the 2700-3300 rpm range) where pressing the throttle more will never cause the Jeep to accelerate more. The above 95% pedal position, I SUDDENLY get full throttle boost and acceleration.

[UselessPickles]

Here's another slightly different chart to visualize the problem (also with new higher resolution data). It shows the relationship of pedal position (x-axis) to ECU-controlled throttle position (y-axis). Sorry for the lack of labelling. I didn't have time to figure out how to add titles and axis labels in the particular version of Excel on the computer I'm at right now.

click for full size


It should be a smooth line/curve such that pressing the pedal more always causes the throttle to open more.

This helps explain the feeling I get in the lower rpm range where pressing the pedal accelerates nicely to a point, then it feels like the engine "bogs down" as I push the pedal more - that's when I get above 25% pedal position and the throttle actually starts CLOSING some as I push the pedal more.

[gbaumann]

Let's hope the Feds respond to car computer security issues by forcing the code to be open source. Their goal will be to have coders and security experts find flaws that could compromise safety. The rest of us will finally get out from under the iron fists if Siemens AG and DiabloSport.

There's a solution to these tuning issues.

[UselessPickles]

BTW, if you are wondering why the manifold throttle position only goes up to just under 80%...

Oops. I explained some of the details a bit wrong. It's just under 80 degrees angle that is effectively full throttle (not just under 80% open). The throttle position is a percentage of 90 degrees. 80 degrees is about 88% of 90 degrees. The throttle position will get up to around 88% at full throttle, but only at higher engine speeds. The ECU reduces the operating range of the throttle blade at lower RPM because air flow rate is much lower, and there's no need open the throttle blade all the way to 88% (80 degrees) to achieve maximum unrestricted airflow at lower engine speeds. By scaling down the operating range of the throttle blade at lower engine speeds, it removes a "dead zone" at the end of the pedal travel near full throttle and makes throttle control less sensitive (easier/smoother) without reducing full throttle power.

[Turbo306]

Were you ever able to rectify this issue?

[UselessPickles]

The jerky part throttle acceleration issues are nearly all cleared up with the latest tune. Current tune is very smooth.

I do still have some small issues during initial engine warm-up that seems to indicate that there may be a problem with some warm-up fueling tables/modifiers somewhere in the tune. Within a couple minutes of a cold start, it's perfectly smooth.

The strange relationship between pedal position and throttle position still exists. I suspect this may be partially caused by the boost source location that Prodigy used while developing the tune. They plan on doing some testing/tuning soon with their boost source relocated like mine (more info here: http://jeeplab.com/showthread.php?13...ull=1#post3590).

Through my new employer, I conveniently have access to a very high quality data logger that can get lots of helpful data at high rates. I continue to provide data to Prodigy, and they will continue to investigate, test, and tune, now on their own dyno

[Turbo306]

Thanks for the updates... Keep us posted

[979garrettmatthew]

Following , pickles what's the name of the tune your running now

[UselessPickles]

Following , pickles what's the name of the tune your running now

I'm now testing a tune named "4.0", and I'm very excited to report that it is VERY smooth now!

The cold start driveability issues seem to be completely gone.

Low/mid RPM throttle response is also much better now. I can cruise around and adjust my speed on the road more effortlessly at lower RPM, downshifting less often.