3 Bar MAP sensor wiring faq

[Razor]

Those purchasing new 3 bar map sensors from AC Delco part numbers 213-1562 or GM 12223861 the sensor is wired internally different than the original TTA 3 bar.

The correction involves swapping the power and ground terminals to it. Whereas old sensor wiring is
A= 5v
B=signal
C=ground

New wiring for 12223861 or 213-1562
A=ground
B=signal
C= 5v

Hope this saves someone from buying the GM harness that reverses the wires for 30 bucks

This only applies to 3 bar map sensor users

 

[fubar2.5]

What will happen if you don't change the wires and plug in boost sensing harness. will it cause any damage.TIA

 

[Razor]

The GN is actually wired correctly as is from factory for the new 3 bar. The TTA is wired reverse on the original 3 bar. The new ones are plug-n-play with the GN wiring. TTA owners need to be careful if changing the sensor..

Will it damage the sensor..if you leave it hooked up long enough..probably the sensor or ecm since it supplies the 5 volts to the sensor.

Question is if you have an old 3 bar or new one..that is the real question..I believe the new ones have the AC Delco sticker on them. The old ones didnt.

But what do I know

HTH

 

[1badTTA]

Guess mine is the original "OLD" one since it has the GM crossover resistor harness.

 

[Razor]

That resistor is there to calibrate it to the factory dash boost guage..someone at GM fugg'd up.. take it out and plug in straight..as soon as you turn on the key, the guage reads 1 PSI not at zero.

Resistor drops the voltage to the sensor..down to like 4.7 from 5 volts. That also drops the zero point from 1.66 to like 1.5 hence the guage reading differently.

 

[S10xGN]

Originally posted by 1badTTA
Guess mine is the original "OLD" one since it has the GM crossover resistor harness.

1bad,

What's the "crossover resistor harness" you speak of? My 3-bar seems to give correct boost readings on T-Link, so can I ASSume it's wired properly?

 

[Razor]

Only found on TTA's.

The 3 bar was made for only one car..the 1989 TTA. This extra plug was added by PAS to correct the guage.

HTH

Un-needed in any other application, unless your restoring a TTA.

 

[fubar2.5]

That cleared it up for me GN & new style 3bar plug & play
Thanks

 

[RKturbo6]

Originally posted by Razor


But what do I know

Ummmm when it comes to alky, I thought everything.

 

[TulsaGN]

Ok....please someone verify my understanding of what is being said in this post.

I read it as if you are a GN owner and are going to the 3bar MAP, you don't have anything to worry about. It's just if you own a TTA and are simply replacing the MAP. Is this correct?

I am in the process of changing over to the ME-R MAFless system and I purchased a 3 bar MAP from Caspers that has the same number on it, 12223861, as listed above. Am I ok?

 

[JasonK]

What about the new 3 bar and FAST?

 

[Razor]

Originally posted by TulsaGN
Ok....please someone verify my understanding of what is being said in this post.

I read it as if you are a GN owner and are going to the 3bar MAP, you don't have anything to worry about. It's just if you own a TTA and are simply replacing the MAP. Is this correct?

I am in the process of changing over to the ME-R MAFless system and I purchased a 3 bar MAP from Caspers that has the same number on it, 12223861, as listed above. Am I ok?

You are good to go and OK

 

[Razor]

Originally posted by JasonK
What about the new 3 bar and FAST?

Whats the new 3 bar sensor you are using?????

See this is exactly why I made this post..cuase there are two varieties of the 3 bar MAP sensor.. and they friggin look the same.

HTH

 

[JasonK]

Ordered it today 12223861......

 

[Razor]

New wiring for 12223861 or 213-1562
A=ground
B=signal
C= 5v


Heres the answer then..if you have a GN..its plug-n-play.

Letters are stamped on the sensor.

 

[JasonK]

I guess I'm confussed, if the new sensor has the 5v and ground swapped then how can it be plug and play?

Jason

 

[Razor]

You dont read..i'll edumacate ya..

the wires are swapped if your trying to install a 12223861 on a 1989 turbo trans am.

If you have a grand national.. you can install plug-n-play. Wiring on new 12223861 is same as the 2 bar that comes with the GN..

Are we crystal

 

[JasonK]

I am sure you are correct but I still would like to know how a harness can be plug and play when the 5v and ground have been swapped? I remove my old sensor and install the new one now I have 5 volts going to the ground side of the new sensor, what am I overlooking here?

 

[Razor]

Ok..do you own a TTA or GN???

If you own a TTA be concerned. If you own a GN..its no concern.

In 1989 when they made the very very very first 3 bar map sensors for the TTA..the wiring was reversed to that of the 87 GN 2 bar.

GM in their infinite wisdom decided to supercede the original TTA MAP with a new updated one..well if you own a TTA..then you buy the new sensor and an additional harness that proveides the swap to install the new reversed wiring sensor on your 1989 Turbo Trans AM.

If you own a GN..then you have nothing to worry about since GM wired the new 3 bars to the GN wiring.

I dont know how many more ways I can explain this...

Hence if you buy a sensor made back in 1989..then its not plug-n-play with the GN. If you buy a sensor made in 2003 then it is..

Better..closer???

 

[JasonK]

I got it this time around, thanks for explaining it in detail. I'm Kinda hard headed sometimes.

Thanks,
Jason