Yet another MAP question

[DGA]

I have made progress with the high MAP readings on this aircraft, LS1, E40, turbonormalised (no boost), by lowering the Engine diag, Airflow, MAP sensor Linear, Offset and Linear B settings. They were originally set the same as the '05 GTO in samples that came with HPT. These were 94.43 Kpa, 10.33 and 31.48 for the three settings. I lowered them all to 70% of that, but made sure the Linear B one was 1/3rd of the Linear value. It is close now, the MAP still goes over 105 but stays in the vacuum range under that most of the time, and the motor runs much better, much more responsive etc.

So, I really don't know if I did the right thing, have I screwed up the slope, the offset or what should I have done to get the MAP to not read 335 Kpa when the engine isn't running, and around 240 with it running? Can someone explain how these settings work and why I might need to lower them?

[DSteck]

Go look at the physical MAP sensor. Take a picture of it and post it.

[DGA]

Will do that tomorrow night. It is the correct one, was the original new one on this LS1 crate engine, and I replaced it with another that did the same thing. I also moved it's location to the back of the manifold to see if there was a flow problem or something. No difference.

[DSteck]

Sounds like there's a problem in your wiring harness somewhere. If its showing 300kPa from a 1bar sensor, that's ~15V out from the sensor.

[DGA]

I thought that too, but it reads 5.00 volts with key on, not running. Hmm, thinking about it now, wonder if the pins are in the correct places on the plug, if that could be backwards or something... will check that today if I can figure out which should be where in the plug.

[DGA]

The sensor that was on the new crate LS1 engine is 16212460, Elmer at LS2.com confirmed that that was correct for LS1/ LS6. The replacement one I have on there now is for an 05 LS2, GTO. That did not fix the problem. MAP reading with key on, motor not running has been 335Kpa typically. I thought I might have been making boost and forced the wastegates open and that did nothing. Without the engine running it should show the local density, about 102Kpa or so.

[DSteck]

I'd say you have a wiring problem.

[DGA]

I checked the wiring at the MAP sensor. The sensor has 5V, Sig Gnd, and Ground on the label on it, and those are what the connector has to it, so I can't say that I have any wiring problem. The Sig gnd and the ground are correct, as is the 5V reference supply. The only thing I have not checked is that it has 5V while running, but as I have said, the sensor shows 335 Kpa with engine off, so it's not a high voltage problem. I disabled the high and low MAP voltage tests earlier, with no change either. Unless someone on here can come up with something, I am to the point of forcing a fix by screwing with the three MAP linear, offset and linear B settings which I still am not sure what is what, but that it is getting the MAP readings down to where they need to be.

[wyochimneysweep]

Scanner setup wrong?

[DGA]

So with the map sensor in the intake you got the black wire first front of the motor then green, brown with yellow strip. even with a sd os with a stock map sensor i can`t get that high of reading of the kpa about 190. Black is low reference ,green is map sensor signal,br is 5-volt reference.

The harness is from fuelinjectionconnection.com so I can't trust the colours, but has the measured voltage and ground, so that part is right.

The scanner is set as it was from HPT. I added another to read in boost PSI, and it showed the same stupid high reading so I deleted it per HPT's instructions. The motor runs like crap typically until it goes under 105 Kpa, then all goes smooth like glass.

[DGA]

Attached a pic of the MAP sensor. It shows in the label 5V, Vout and GND. Those correspond correctly to the plug, looking at the PLUG end of the wire, the left pin has Ground, this is a direct, no resistance connection to the engine, multimeter to the head and it has no resistance. The middle one does not connect to ground with the key off but has some resistance when it is on. The left one has 4.99 Vdc with key on.

[wyochimneysweep]

Add the map volts pid to the scanner and see what volts the ECM sees

[DGA]

Only two volts in the scanner I see are Mass air flow volts and Throttle volts. Either one of those work for ECU voltage?
Edit, Ok, I got it I think, will go try that now.

[DGA]

So looking at wireing harness plug stock. A is the low reference. B is map sensor signal. C is 5-volt reference. I need more info on what wire harness thay sold you. I looked could not find anything on it. I was when i made this so gran of salt.

Fuelinjectionconnection is in Colorado. The owner (?) Robert Wooldrik is quite knowlegable, but once you give him your money, he dissapears. 6 weeks later you might hear from him, he wont answer his phone, email or texts. I finally got the harness and ECU with base program and only got hold of him one more time, he drops off the face of the earth after that. He said he would help get this thing going with the programming but that didn't happen. The harness was made for this plane, for LS1 but with E40 ECU and the 90mm throttle body. I changed the intake manifold to the 4 bolt LS2 throttle body type and put the MAP sensor by the TB instead of the back of the manifold where the LS1 had it.

[DGA]

The voltage PID didn't work for some reason so I don't have any data on that. I might try putting the MAP linear and Linear B back to original tomorrow and see if the offset does just that; offsets the MAP signal, like calibrating it I guess.

[IDRIVEAG8GT]

Determine if it's wired for either a Bosch or Delphi sensor.

[DGA]

No codes on the throttle setup. Throttle body is the LS2/LS7 type, and is new. ECU is an E40 from a Trailblazer, and the base program is from a Saab 9/7 something. Throttle 'pedal' is not that, but a BEI sensor on my own throttle lever, aircraft setup remember.
Problem is really still that on key on, engine off I get 335Kpa MAP readings. Only way I have changed that is by offsetting the MAP offset etc values. I don't know what sensor it is set up for, but the wiring and voltages etc match what the sensor requests on the little sticker on it, as in the pic in a few posts above.

[wyochimneysweep]

post the tune?

[DGA]

Sure, attached here.

[wyochimneysweep]

lincense is for a two bar and sounds like you have a 1 bar sensor installed.