So it seems like most everything naturally aspirated in the 80s to 2005 ran the 1 BAR 12219927 MAP sensor. That sensor commonly was connected to the 3 tower green connector.

The 4.9 uses a different MAP sensor. It uses a 12219931 1 BAR MAP sensor. It mates with a red connector with different keying than the green one.

Why, and what is the difference between the two sensors?

I am doing a 4.9 harness for someone. I had one in the works but I held on sending it till I got their hack job donor 4.9 conversion harness. I see that they had a green MAP connector and thus must have used the wrong sensor on the engine (I assume).

Not all 4.9's have the red connector. I've seen red, black, green, and grey. I never noticed any difference in the MAP sensors themselves. Phiscally then are all identical with the exception of cast in numbers. I have several off of different year 4.9's at the yard and at least one V6 fiero MAP. All seem to work fine without any changes to the wiring. Scanner results always seem to stay the same. Other then that I don't know much else about them.

I'm interested in seeing if you find anything out.

[This message has been edited by Fieroseverywhere (edited 10-15-2011).]

But you do see that the red or gray ones are keyed different than the Green right?

And the 2 bar Orange or White ones are keyed different than both also

If you hold the connector with the tab up, and look at the 3 barrels here are the cuts - by time, ie 3:00

Green - 3:00 - none - 3:00

Orange or White - 9:00 - 6:00 - none

Red or Gray - none - none - 12:00

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btw - Brown TPS connectors look the same but are clocked

Brown - 12:00 - none - 12:00



A 2 Bar connector (orange) but shown without the key cuts

[This message has been edited by phonedawgz (edited 10-15-2011).]

I did not notice that. Apparently I have had good luck because all of mine fit the connectors I have.

My car currently has a red connector. I replaced the original black one at one point because it was broken. Both were clocked the same as I would have noticed immediately if the connector didn't fit. I have also swapped to a few different MAP's over the years but never had an issue.

The current 4.9 swap we are working on also has a grey connector with the same 12'o clock key. I double checked and both maps on these two engines and the two extras I have are all clocked the same. Both engines are from Devilles, 92 and 93 respectively.

How is the one you have different? Do you know which model caddy the engine came out of? I'm wondering if the 91-93 Deville/Fleetwood vs 91-93 Eldorado/Seville (and 94-95 deville) wiring changes have something to do with it. These changes include the dual VS single O2 sensors. The latter being dual. This is my only theory at this point. I'll check wiring schmatics for these different models and let you know if I find anything. I currently have 91 deville, 92-93 deville, and 92 Seville diagrams handy.

quote Originally posted by phonedawgz: I see that they had a green MAP connector and thus must have used the wrong sensor on the engine (I assume).

It might be wrong, given that it is not the OE part number specified for that engine, but is it the wrong sensor? It would seem to be a simple test to see if any 4.9 would run normally with a 9927 MAP. It would be pretty easy to make a jumper between the 9927 sensor and the harness for a 4.9 that uses the 9931 and then run the car/engine and see if it operates properly - by monitoring the parameters with a scan tool or laptop. Doing such a test on a car with a 4.9 might shed some light on the difference.

Sorry for the delay. I confirmed with the wiring diagrams. All PCM MAP pins remain the same for both Deville and Seville installs. This does not confirm or deny the use of different MAP's but it does show no pin changes for the wiring.

Rockauto lists the same number for MAP on both models. The airtex/wells replacement MAP however does state pigtale 1P1064 may be needed. If the picture is correct this new pigtail have "A" and "C" pins clocked at 12.
http://www.rockauto.com/cat...reinfo.php?pk=935954
Hope this helps and doesn't just confuse the issue more by adding yet another different choice for key clocking. Black = 12:00 - none - 12:00

[This message has been edited by Fieroseverywhere (edited 10-16-2011).]