CALL911

iTrader: (17)

I started the thread here> https://ls1tech.com/forums/pcm-diagn...help-asap.html

But so far I have had no replies, so I thought by possibly asking the question in the FI section I may get someone with more knowledge on it.

Basically I have a 1 bar map sensor, and want to swap it out for a 2 bar map sensor, but the plugs are different and need help figuring out what pigtail I need to swap it to and if it can be done with a simple splice and re-wiring of it.

I "think" that I just need to get an LS1 style map sensor pigtail for the GM 2 bar map sensor, and that it should work okay. If thats the case I "think" I may be able to just swap the pigtail out for my current LT1 style map sensor pigtail, but it would be really nice to hear from someone who knows.

Pics show everything in the other thread. I would really appreciate any input ASAP. I have an appointment for a full dyno tune in just a couple days and need to get this figured out very quickly.

silver_82

If I remember correctly you have the old style black box map sensor, you can get a 2 bar in the same configuration, and wouldnt need to swap connectors

http://www.summitracing.com/parts/msd-23121

If you really want to use the smaller (newer style)2 bar sensor then make sure its actually a 2 bar, theres a million different versions out there. And yes you can cut off your current plug and put on the new style.

Make sure you get the pinout correct, and I prefer crimping on new pins/seals over soldering wire to wire. I have the proper crimping tools, so let me know if you need me to do it

silver_82

btw. dont expect it to run correctly after you do this, in fact dont try and start it at all. the map scaling will be all wrong

CALL911

iTrader: (17)

Hmmm...

In all my research of looking to go with the different map sensor I never came accross that one. I know that the 3 bar map sensor seems to share the same connector as my 1 bar, but all the 2 bars I have seen didn't resemble that (and they were only good to 14.7 pounds of boost instead of 29).

Unfortunately I found this so last second that I can't wait on shipping. Being memorial day, everything seems to be closed, and I will need something to work tomorrow to have with me Wednesday very early morning. I plan on swapping out connectors on the dyno and will need the current one in so I can start the car and get it onto the dyno, so I can't do the swap until its already on the rollers.

I think my best bet is to try to get the LS1 style connector from a dealership tomorrow, then put it on the car on the dyno.

CALL911

iTrader: (17)

Or, I could make the full drive to Summit tommorow and get the other map sensor that would be a plug and play (but it would be a PITA to drive out there and back).

CALL911

iTrader: (17)

Just to be clear, it should just be the same colored wire for the same colored wire shouldn't it?

Gonoma

iTrader: (15)

See if the parts store like advance can get you one from a 97 Pontiac grand Prix w/ 3.8 supercharger...it is a 2 bar sensor and will fit in place of your old one

CALL911

iTrader: (17)

Good idea!

One question I do have though, are all two bar map sensors as capable as the others?

I know there was a discussion of 3 bar vs a 2 bar, and it seemed that the 2 bar would be better suited to read more down low than the 3 bar (but if you ran high boost over 15 psi that you should still go with a 3 bar).

I just called and Autozone has the 2 bar map sensor for that model grand Prix. I just want to make sure the part will do what I need just the same as the GM Cobalt SS 2 bar map sensor will.

silver_82

Beats me, you have an aftermarket harness, They may or may not of used the OE colored wires. That was my main concern. The layout is the same between the sensors, but you would be surprised how many people still get it wrong

Old style map pinout

A-GRND
B-signal
C-5V ref


newer style map pinout

A-GRND
B-signal
C-5V ref

Gonoma

iTrader: (15)

The two bar will have better resolution (accuracy) than the 3 bar but if you do go over 15psi I would get the 3 bar from an 89 Pontiac trans am with the 3.8 turbo

silver_82

if you never go above 15psi there is no reason to put in a 3bar. The lower bar sensor has a more precise resolution. The factory 2 bar, bonneville/GP sensor is fine


^^^ treed.

Gonoma

iTrader: (15)

And I noticed the msd map from summit says up to 20psi but I believe that info is wrong if that is why you were asking

CALL911

iTrader: (17)

Chris, and Gonoma, thank you so much for your quick help today.

I think for ease of things I will just buy the Map sensor out of that Grand Prix so its a direct plug and play and I don't have to go splicing wires in the dyno.

My car regularly would not see 15 pounds of boost (it normally would see about 13.5#'s). I just installed larger heads which should drop the boost a little, so the 2 bar should be fine.

CALL911

iTrader: (17)

That was exactly what I was asking. Thanks for the clarification.

silver_82

good idea.

Gonoma

iTrader: (15)

Glad we could help!

CALL911

iTrader: (17)

Well, I found out today while at the dyno that the map sensor out of that grand Prix IS NOT a direct plug and play for my MAP. Looking at it, it seems like it would be the exact same. But it did not directly plug in.

The 3 pins in the connector are protected by 3 plastic plugs. These plugs have a slit down one side of them. The slits in the grand Prix map sensor are different and will not plug, until you make new slits. I cut the plug with a razor blade to make the plug fit, but I was expecting just a direct plug and not figure it out.

At any rate, can someone verify this is a true 2 bar map sensor? The dealer couldn't verify it and the part number is showing it could be a two or three bar map sensor.

Gonoma

iTrader: (15)

I forgot they were like that... its done that way to prevent ppl from putting it on a car that isn't tuned for it...regardless is a lot easier and cleaner than trying to make an ls1 map sensor work...at least I think so

LS1 240sx

iTrader: (1)

I went with
http://www.frsport.com/Connector-plu...or_p_9961.html

and

http://www.frsport.com/GM-3-Bar-MAP-Sensor_p_10051.html


Even thou im only on 14 psi it works fine never had any issues with resolution, then again im using HPtuners, im not sure what software you are using.

CALL911

iTrader: (17)

Gonoma, I do agree that it is still easier than wiring an ls1 style connector. Can you (or anyone verify that the 97 Grand Prix 3.8 is a 2 bar?