Map sensor plug?

[j13smiley]

thanks for the info guys...

still need to get an alky kit from razor some day...

 

[dvernst]

Green wire on 3 bar is suppossed to show 1.6 volts normally. On the TTA with the added resistor its about 1.5 volts. This is KEY ON engine not running.

So if your green wire measures 1.5-1.6 volts there is no way it will show 17 PSI on your dash unless your factory boost gauge gave up the ghost.

Green=center pin on all harnesses.

Measuring from the green wire to ground I get .07 volts with the plug, or without it???

 

[Razor]

Measuring from the green wire to ground I get .07 volts with the plug, or without it???

Ignition ON, sensor plugged in?

No way

 

[dvernst]

Nope. Ignition was on, but the sensor was unplugged. Now that I think about how the sensor works no wonder there was no voltage on the wire! Duh! I'll check it again tomorrow. Thanks...

 

[Razor]

Nope. Ignition was on, but the sensor was unplugged. Now that I think about how the sensor works no wonder there was no voltage on the wire! Duh! I'll check it again tomorrow. Thanks...

You cannot test devices when they are not plugged in :redface::wink:

 

[dvernst]

O.k. I've got 1.5 volts with the harness, and 3.56 without it. Guess I know why the gauge is stuck on 20. Do you think it's a bad Map sensor?

 

[Razor]

I think your polarity is being reversed without the harness. Watch where the gray and black wires go to the sensor.

Your sensor is ok.

 

[dvernst]

O.k. I'll check it out tomorrow. Thanks...

 

[Sweet6]

I just undid my plug. The MAP volts went up about .8volts after unplugging it. No other effects.

 

[alwayscode390]

I am coming from SYTY land with regard to boost.

I have two 3 bar maps ( one will be in the Syclone to go past 14.7 lbs boost ).

Do these cars need an upgrade or should I sell my extra peice ( I tried searching TONS and I kept getting "blank" is thrown out of this search (bar,map, 3, ect ) ? ---

 

[Razor]

I am coming from SYTY land with regard to boost.

I have two 3 bar maps ( one will be in the Syclone to go past 14.7 lbs boost ).

Do these cars need an upgrade or should I sell my extra peice ( I tried searching TONS and I kept getting "blank" is thrown out of this search (bar,map, 3, ect ) ? ---

You cant ever have enough spares when trying to figure out a problem.

The Syclone will need a completely different chip to work with the 3 bar.

As of today, there are plenty of 3 bar maps available in the market place and they never go bad. or better yet.. rarely.

 

[dvernst]

I think your polarity is being reversed without the harness. Watch where the gray and black wires go to the sensor.

Your sensor is ok.

O.k. finally checked this thing out. Yes the Harness reverses the polarity. The plug from the car has Gray to A, Green to B, and Black to C. Is this something you've seen before?

 

[Razor]

O.k. finally checked this thing out. Yes the Harness reverses the polarity. The plug from the car has Gray to A, Green to B, and Black to C. Is this something you've seen before?

There are two plug extensions. One is the factory one that corrects the gauge(has a built in resistor to drop volatge). The other one is from GM in case you replace the MAP sensor so it corrects the wiring.

All GM MAP sensors are Black A, Green B, and Gray C. Except the 89 TTA 3 bar.

The TTA was wired Black C, Green B, and Gray A.

GM supplies a harness that flips the wires to allow a 3 bar to be used on a TTA. If you buy a 12223861(3 bar sensor) from GM for a TTA, it tells you need the harness to flip the wires.

Making this worse is the lack of markings on the OEM 3 bar to designate it as such. New MAP sensors at least carry the decal on them. Unless they're chinese imports without. More drama :redface:


Straight forward as mud.. I know.

 

[dvernst]

There are two plug extensions. One is the factory one that corrects the gauge(has a built in resistor to drop volatge). The other one is from GM in case you replace the MAP sensor so it corrects the wiring.

All GM MAP sensors are Black A, Green B, and Gray C. Except the 89 TTA 3 bar.

The TTA was wired Black C, Green B, and Gray A.

GM supplies a harness that flips the wires to allow a 3 bar to be used on a TTA. If you buy a 12223861(3 bar sensor) from GM for a TTA, it tells you need the harness to flip the wires.

Making this worse is the lack of markings on the OEM 3 bar to designate it as such. New MAP sensors at least carry the decal on them. Unless they're chinese imports without. More drama :redface:


Straight forward as mud.. I know. [/QUOTE

So according to GM if you get a new 3 bar Map you're supposed to plug in 2 harnesses to reverse the wiring, and have the gauge read correctly?

 

[Razor]

So according to GM if you get a new 3 bar Map you're supposed to plug in 2 harnesses to reverse the wiring, and have the gauge read correctly?

correct. one is for polarity, the other is for calibration.

 

[dvernst]

Finally removed this add on harness. Boost reading has been off on the Powerlogger. Had to switch the black and gray wires on the factory plug after removing it.