MAP Sensor reading low

[500hpduramally]

I’m having a problem with my map sensor reading low. It’s reading about 11.7psi. Baro is around 14.2 psi. The truck seems low on power and the turbo vanes are closed up to 90% most of the time. The problem started after I installed a bunch of parts. Danville turbo and tunes, wcfab piping, and injectors. I’ve installed a new gm map sensor and still reading the same. Truck throws no codes. I’ve wiggled the wiring harnesses and watch map reading and it doesn’t bounce around at all. I’m thinking it’s wiring somewhere but does anybody have any ideas what else it could be? Does anybody know what kind of volts I should be seeing ay the map? Thanks in advance

Truck is a 2007 lbz

 

[DAVe3283]

Can you flash the stock tune back in and check the reading? You don't need to start the truck, just key on and see what it reads.


That will tell you if the tune is the problem or not.

 

[500hpduramally]

I don’t have the stock tune as it already had tunes from
Another tuner on it when I bought it

 

[DAVe3283]

From your description, I thought you added tunes at the same time as the parts. If the tune didn't change, it kind of eliminates that as the problem.


You may want to pull the connector off the MAP sensor and verify the supply voltage matches the other sensors. I think the LLY is like the LB7, and wants 5.00 volts to the sensors. Though I usually see closer to 5.1 volts on the sensors, as long as they all match, that is fine. So measure the MAP and Baro and see if they are the same.

 

[500hpduramally]

Yes I did change tunes to Danville at the same time. But I didn’t save a readout because it already had tunes from another company on it and was told not to read the ecm before flashing. I’ve talked to mark and he said it’s not the tune. I’ll check voltages

 

[500hpduramally]

So I’ve checked voltage with truck off key on with the sensor unplugged. The orange/black wire it’s was 4.86volts. The light green was 4.96 volts. I don’t know if that means anything? I also got a stock tune file and flashed it and the reading stayed the same. So tune is not the problem it looks like