Quadzilla stumbles @ max TPS WT %

[tony.canto]

I just installed a quadzilla and an isspro boost guage last week and I'm seeing the same discrepancies as rogerash0. Isspro shows 10 and the quadzilla is showing 2-4. I am still running stock injectors and turbo though. 

Edited July 29, 2020 by tony.canto

[Mopar1973Man]

22 hours ago, Me78569 said:

@mopar1973man what would be the cause of a lazy map sensor in terms of voltage?  I can't remember if it is a pull down or pull up sensor? 

 

No idea...

 

All I know I've never seen one Quadzilla yet with accurate boost numbers. I love looking at my logs and seeing Quadzilla reporting some crazy super high boost number. Right now I'm pretty sure my wastegate is blowing open easy. I top out at 35 PSI of boost (ISSPro EV2) and sure enough the Quadzilla will report like 45 to 50 PSI. Previously I was getting 47 to 49 and it would report 67 to 69 PSI of boost in the logs. The only time mine is close to right is below 25 PSI.

Edited July 30, 2020 by Mopar1973Man

[Me78569]

The main thing is below 16 psi. 

 

When boost is below 16psi the quadzilla is reading the canbus message and sniff out the reported boost number from the ecm.  It is NOT reading the sensor directly.

 

In situations below 16 psi where boost on the quad is not matching a mech gauge we know for a fact that the ecm is not getting an accurate read from the sensor or the ecm is not reporting an accurate read on the canbus.

 

This is not a quad issue rather an issue somewhere else in the system. 

 

Boost numbers over 30 psi not being accurate are not really a big issue. 

[Mopar1973Man]

It is when people don't have gauges and trying to use strictly the Quadzilla for gauges. I al ways highly suggest gauges vs. Rely on digital tuner. Even Edge has this same problem. 

 

I more or less just use Quadzilla boost reading for diagnostic more so. Use boost gauge is more accurate and Quadzilla will at least tell you if the sensor is working. Thats it. Accuracy just isn't there.

[Me78569]

However there is an issue if the ecm is not seeing good boost reads.     My truck was perfectly accurate until ~25 psi.  

 

question is would low 5v source to a 5v reference sensor cause a lazy map read?  Maybe a damaged voltage regulator on the 5v bus?

[rogerash0]

Would it be reasonable to backprobe a 5v circuit with a fluke while the truck is running to see the delta from 5v? I know atleast on computers you never have a perfect 5v on the 5v rail, its always +/- say 0.25v depending on the PSU.

[Me78569]

I believe it should be voltages between 4.5 and .5 voltage.  I dont remember if the sensor is a pull down or pull up sensor.  So at 0 psi I would expect to see either .5 or 4.5v, then as boost comes up I would want to see voltage change.  

 

I've never been able ot have hands on a truck that does what yours is doing so I am only guessing, but maybe the 5v bus is off causing that 0 psi  reading to hold on longer?  I dunno.