HOV

Long story short: I installed a DTT Shift Enhanser. But in the process, the ground wire for my Quadzilla XZT gauge set got disconnected and the truck was powered up with an open ground.

Threw a bunch of codes: water in fuel, fuel pressure sensor voltage, boost sensor voltage. Finally figured out what the problem was, but when the truck got running again I had only 50% power (I was flashed to Smarty Jr. Econ at the time).

When I flashed to Smarty Jr. Performance setting, the truck was drivable and fairly peppy. Felt about what it normally feels like on the performance setting.

When I flashed back to stock, the truck was undrivable - maybe 10% power. Couldn't hear the turbo spool (and my gauges were fried so I couldn't see the boost level either).

So my question is this: what is unique about the Smarty Jr. Performance setting that allows my truck to be not only drivable but more powerful than stock, but every other setting is at 50% or less power?

My theory is that I fried the MAP sensor, and that Smarty Jr. Performance has enough boost fooling built in that things feel fairly normal.

XLR8R

Plausible... and what about the difference in rail pressure between stock & JR. Performance?

HOV

I don't have a rail pressure gauge.

Dodgezilla

I can't help you with the Smarty question but if one of your codes was for "Low Boost" then your truck is probably in limp mode. Either that or maybe one of the other codes put you in limp mode. Do you have a code clearer? If not, I can bring mine over and see if that helps.

rip 112

Try to clear your codes and leave your batteries disconnected for a few hrs. Its a small step but it may help.

.boB

The Smarty Jr should be able to read and clear codes. Mine does, anyway.

HOV

I've cleared all codes. With the gauge set removed, no more are being set. So right now I have a truck with 20% power on stock settings with no codes.

Dodgezilla

The next step I would take is to remove the Quadzilla box from the truck completely and see if that helps. You may have messed it up somehow...

BigJohnston

I am just throwing out an idea. Did you set it to level 0 (50% power) on the Smarty or did you select return to stock?

HOV

I don't have a quad box, just the XZT gauges. I removed those once I started getting a recurring P0071 DTC. Once they were removed, the DTC stopped popping up but the 20% power issue is still there.

I definitely did not set it to 50% power, as the Smarty Jr. doesn't have that setting.

Does anyone know how the MAP sensor actually works? I'm wondering if the voltage spikes somehow miscalibrated the sensor.

BigJohnston

I had a bad MAP sensor but with the boost fooler built into the Quad box truck was able to run ok as long as the Quad box was hooked up, it didn't even need to be set to a power level.

The MAP sensor works on a 5 volt system 0 volts being no boost and 5 being max boost. Quad actually was showing people how to make a smoke switch by shorting the entire 5 volts past the MAP sensor which made the truck fully fuel because it thinks it has max boost. You could put a small resistor inline and this should make your truck think it has decent boost and give you a good amount of fuel. It would be a little smokey on the bottom but should give you most of your power back if the MAP sensor is the problem. Good Luck, Tom J.

HOV

I'm fairly convinced the MAP sensor is the problem now. My gauges may not be fried - they work just fine for EGT's and trans temp, but boost shows zero. Considering it's reading boost from the MAP sensor signal, I think that's a pretty good indicator the sensor is not working.

HOV

BTW, thanks for the info. It was helpful.

BigJohnston

That is what this forum is for, helping people. I know that there are lot more knowledgable people than me but if I think I can pass some info I am happy to do so. Good Luck, Tom J.

HOV

End of story: I replaced the MAP sensor and all is well again.

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