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rwoody
01-22-2013, 11:07 PM
i ordered 1 for my 94 think they are all blown or close to being blown

my 90 which i just sold was doggy~
i checked the old sensor and it was blown as it didnt change when vacumn was applied.

the interesting thing is the factory sensor on the 90 and my 94 and don bartletts are are 2 bar sensors--our 8v require a 3 bar sensor.

i bought this here is what i used
http://www.ebay.com/itm/160835316620

the 90 40 wb was a hot rod~! ask the new owners~~

THIS CAN ALSO APPLY TO S60 SO CHECK YOUR NUMBERS

to explain here is some information via
http://www.robietherobot.com/Storm/mapsensor.htm
the logic module uses the manifold absolute pressure (MAP) sensor to determine the absolute pressure (not the relative to atmospheric pressure) of the air inside the intake manifold and the atmosphere (barometric pressure).
This information is used to determine the density of the air entering the combustion chamber (in conjunction with the IAT(Intake Air temperature) sensor), which is used when calculating the proper air/fuel mixture for the engine, especially at WOT since the system is not in closed-loop at this time.
It is also used to help adjust the IAC(Idle Air Control) motor during idle.
It uses a silicon wafer that is thinner in the center (0.001") than around the edges (0.045"), which causes it to act as a diaphram.
It is mounted with a perfect vacuum beneath the chip so that the air pressure from the other side flexes the chip.
This flexing causes a change in resistance and the circuitry inside the sensor converts this to a voltage ranging from 0.02V to 4.94V when the output is pulled up towards 5V by the ECM(Electronic control module).

1 Bar MAP sensors are used on NA(naturally asperated) vehicles.
2 Bar MAP Sensors are used on forced induction vehicles(Turbo & Supercharged). They can measure up to 2x the apmospheric pressure(29.4psi), so that means it can measure up to 14.7psi boost(the atmosphere is 14.7psi + 14.7psi from the turbo/supercharger).
3 Bar MAP sensors can measure up to 44.1psi, which translates to 29.7psi boost from a Turbo/supercharger.
http://i34.photobucket.com/albums/d119/Robie01/Projects/MAP/GM20320bar20map20pic203.jpg

moush73
01-23-2013, 10:40 AM
OK Woody, you've got me curious. I want to check mine. Were are they located? Paul

mburmandds
01-23-2013, 11:34 AM
Didn't even know about the MAP sensor on a 8v92. Now I have to know!
What do I do next?
If the sensor is bad, is it an all or nothing thing, or can the engine run progressively poorly until the sensor is replaced?
Thanks
Mike

brhodes
01-23-2013, 01:00 PM
Mary and I purchased Woody's 90' "Northern Lights" and he is correct. This Bird with the 8v92 wanting to run as we were cruising at 70 mph most of the way home right at 2000 RPM and she still wanted to run faster which was something we had to watch with all the troopers we saw.
The idle is very smooth and the response off the line was excellent, even towing Mary's Taurus on a tow dolly.
Fuel consumption was close to 5.5 mpg which we are very happy with.

It was fun watching everyone who passed us, waving and even had some Japanese tourists, hanging out the windows of their car taking pictures. Just proves how wonderful these great machines are. We even had a car from Alaska pass us waving and blowing their horn so we opened up the duel air trumpets to return the hello.

We have her currently in secure storage as we are having a new 10-12" concrete parking area installed next to the garage so we have easy access for service, loading/unloading and ensuring she gets taken good care of.

Mary and I want to again THANK WOODY, for being such a great individual, patriot, and we hope a friend for the rest of our lives as he is welcome in our home always.

rwoody
01-23-2013, 08:28 PM
OK Woody, you've got me curious. I want to check mine. Were are they located? Paul


PAUL
locate a 1/4" line off pass side intake
the map is at the end of this hose:)

rwoody
01-23-2013, 08:29 PM
Didn't even know about the MAP sensor on a 8v92. Now I have to know!
What do I do next?
If the sensor is bad, is it an all or nothing thing, or can the engine run progressively poorly until the sensor is replaced?
Thanks
Mike

i dont know but for sure they give low boost when not working

im a believer in changing them on ford diesels when they get older

the engines in out units are not any different;)

brhodes
01-23-2013, 08:51 PM
Detroit Diesel SENSOR SERIES 60 #23527829 TURBO BOOST PRESSURE map.

http://i.ebayimg.com/t/Detroit-Diesel-SENSOR-SERIES-60-23527829-TURBO-BOOST-PRESSURE-map-/00/$%28KGrHqQOKjwE3VhyY8L%21BN6dzSgP+w%7E%7E_12.JPG









(http://www.ebay.com/itm/Detroit-Diesel-TURBO-BOOST-SENSOR-DDEC-GM-MAP-12219935-28182633-16070629-/160835316620?pt=Other_Vehicle_Parts&hash=item2572882b8c&vxp=mtr)



Detroit Diesel TURBO BOOST SENSOR 8V92 DDEC ~ GM MAP 12219935 ~ 28182633 - 16070629 (http://www.ebay.com/itm/Detroit-Diesel-TURBO-BOOST-SENSOR-DDEC-GM-MAP-12219935-28182633-16070629-/160835316620?pt=Other_Vehicle_Parts&hash=item2572882b8c&vxp=mtr)

http://thumbs1.ebaystatic.com/d/l225/m/mW3Ov_q9RyYxeOfcAXZku-Q.jpg


Hope this helps

giderich
04-18-2013, 09:31 AM
According to the .pdf below, the vacuum port needs to be pointed downward. Blue Bird mounted the GM Factory style MAP with vacuum port in the horizontal position. Pointing the port down will allow liquid or condensate in the line to drain away from the sensor cell. This may affect longevity?

http://www.powerandsignal.com/docs/Products/12219935.pdf

Note: Prior to our ownership, W.W. Williams of Phoenix, replaced the MAP sensor on our '88 WB 8V92 and I found 4 items that were troubling.

1. 5/16" vacuum hose used instead of 1/4", resulting in leaking connections at the supercharger as well as at the MAP.

2. A 2-BAR MAP was installed instead of a 3-BAR.

3. The electrical connector at the MAP was broken is 3 places and was zip-tied; I have replaced with a new MAP #12223861 and pig tail.

4. MAP was reinstalled with vacuum port horizonal instead of vertical per the Delphi .pdf drawing. Read note #4 in the .pdf below.

http://www.powerandsignal.com/docs/Products/12219935.pdf

giderich
04-21-2013, 09:01 AM
The MAP sensor has a 1/4" diameter ribbed plastic nipple, and this hose connecting to the nipple is subject to swelling or splitting at the MAP sensor. Any loss of vacuum/pressure at the MAP sensor will send erroneous data to the MAP sensor and/or the ECM. Replacing the cheap MAP sensor hose with a piece of 1/4" internally reinforced fuel hose will improve the connection both at the MAP sensor and at the barbed nipple on the roots supercharger.

I suggest installing new Corbin type clamps on each end of the new hose running between the blower (supercharger) and the GM factory style MAP sensor.

Some pics of the GM factory style MAP sensor used on my 1988 DDEC I equipped 8V92 Detroit diesel.

http://www.google.com/search?q=GM+factory+style+MAP+sensor&rlz=1T4RNWE_enUS310US310&tbm=isch&tbo=u&source=univ&sa=X&ei=b-FzUaq5IYXYqgGy84GIDQ&ved=0CH8QsAQ&biw=1280&bih=767

MrBlueSky
05-27-2015, 08:35 AM
Can anyone confirm if #12223861 (or any other model) map sensor works on 8v92 DDEC2? DD calls for #12219935 (rarer/more expensive). Only difference seems to be range of operating pressure. #1229935 is 70-300kpa. #1223861 is 40-304kpa (see attachments).

Ask b/c replaced by 2 bar with what was called 3-bar #12223861 "upgrade" from ebay. Didn't work. Check engine light came on & spit codes 33/34. Only 5 psi boost max. But...discovered if backed off accelerator so boost dropped to 0, engine light went off & full boost returned (17psi or so). And...if coasted so boost hit 0, engine light returned & max boost again limited to 5 psi. Process repeated predictably for recent 3 hour run. Weird. Obviously need to replace my "new" map sensor. But would like to confirm what works before blowing more money. Simply bad part? or need to use only the #12219935.

rwoody
05-27-2015, 08:24 PM
BAD SENSOR..ALL SHOULD WORK

KCSS
05-27-2015, 09:10 PM
X2

Randy Dupree
05-27-2015, 11:03 PM
KC,in our Alaska group we have 3 S-60 birds.
we all decided to replace the MAP sensors,coachs are 2000,1997 and 1995 models.
How long do MAP sensors last?
I have no idea,so we bit the bullet and bought new ones.
The 97 and 95 engines took the same one,my 2000 took a different model number,it even looks different.
the 2000 engine has/had a waste gate turbo,the 97 and 95 do not have a waste gate turbo.
My engine has a new non-waste gate turbo,the non-waste gate is supposed to get better fuel mileage,but i can see no truth in that,yet.

so,we replaced MAP sensors,and we all have Silverleafs,and we all have the same fuel mileage we started with.
I do get 2 more Lbs of boost at WOT,but they may be because of cooler air.

I'm thinking i need to borrow one of the used MAPs and install it on my 2000,just as a test.

Good thread,keep the info coming.

MrBlueSky
05-28-2015, 07:55 AM
Woody, KC, and Randy, thanks all for the information / input.
KC: Thanks for PM. Ebay seller doesn't think MAP is bad but will replace it, so I'll try again. If it don't work, I'll order OEM DD # and let you know. Your similar problem seems to indicate cheap, import MAPs, at least 1222381 'upgrade' won't work. Wonder if its b/c DD specified sensor where range begins at 70kpa, rather than 40kpa. Agree that no matter the model, we might have to tweak / trick DDEC to get more boost. Can't seem to get more than 16-17, and wonder if that's by design & why they originally installed only 2-bar MAP.
--Bill

KCSS
05-28-2015, 07:56 AM
KC,in our Alaska group we have 3 S-60 birds.
we all decided to replace the MAP sensors,coachs are 2000,1997 and 1995 models.
How long do MAP sensors last?
I have no idea,so we bit the bullet and bought new ones.
The 97 and 95 engines took the same one,my 2000 took a different model number,it even looks different.
the 2000 engine has/had a waste gate turbo,the 97 and 95 do not have a waste gate turbo.
My engine has a new non-waste gate turbo,the non-waste gate is supposed to get better fuel mileage,but i can see no truth in that,yet.

so,we replaced MAP sensors,and we all have Silverleafs,and we all have the same fuel mileage we started with.
I do get 2 more Lbs of boost at WOT,but they may be because of cooler air.

I'm thinking i need to borrow one of the used MAPs and install it on my 2000,just as a test.

Good thread,keep the info coming.

I'm in the midst of running MAP tests now. Sent PM to Bill Anthony (Mr Blue Sky) last night with details. Will post findings & results next day or so. ;););)

Dieselbird01
05-28-2015, 11:33 AM
Pretty much everything I know about Detroit Diesel MAP sensors comes from this thread but based on the information in this thread, it looks to me like the 2 Bar sensor would be the correct one for our 8V92 turbocharged engines.

If I’m reading it correctly, the 2 Bar sensor would have an output of 4.94 volts at 29.4 psi and the 3 Bar sensor wouldn’t reach 4.94 volts until 44.1 psi.

If I understand the DDEC operation properly, the DDEC allows more fuel to be added if the MAP sensor senses that there is sufficient air being forced into the cylinders to be able to burn the extra fuel.

From that it looks to me like, a 2 Bar sensor would be calling for full fuel by 29.4 psi and that the 3 Bar sensor wouldn’t be calling for full fuel until 44.1 psi which we never reach.

Randy Dupree
05-28-2015, 11:54 AM
John W,we are talking about turbo boost pressure?
24.9 lbs of boost,as sensed by the MAP?

also,i think the 8V92 map has a rubber hose that connects it to the engine.
the S-60 bolts to the manifold and has an o-ring seal.

Dieselbird01
05-28-2015, 12:11 PM
John W,we are talking about turbo boost pressure?
24.9 lbs of boost,as sensed by the MAP?

also,i think the 8V92 map has a rubber hose that connects it to the engine.
the S-60 bolts to the manifold and has an o-ring seal.

Yes on the boost and yes on the hose.

brhodes
05-28-2015, 12:20 PM
2 Bar MAP Sensors are used on forced induction vehicles(Turbo & Supercharged). They can measure up to 2x the atmospheric pressure(29.4psi), so that means it can measure up to 14.7psi boost (the atmosphere is 14.7 psi + 14.7 psi from the turbo/supercharger).

3 Bar MAP sensors can measure up to 44.1 psi, which translates to 29.7 psi boost from a Turbo/supercharger.


3 digit numbers for identification stamped on rear of sensor:
1 Bar: 039, 460, 883, 876, 153
2 Bar: 886, 012, 539, 609, 701
3 Bar: 749, 861

KCSS
05-28-2015, 01:05 PM
Here is the PM I sent to Mr Blue Sky. I will test run the coach this afternoon.

I am having somewhat of the same problem - what was called 3-bar #12223861 "upgrade" from ebay. Didn't work. No acceleration. No boost until 1/2 way thru 2nd. gear.
Been researching MAPs heavily and also talking with knowledgeable WOG members.
I am no x-purt by far but my research has given me several ideas. My understanding of how these things work comes mostly from the internet (you tube & bus conversion forums) plus WOG members. It appears the MAP output voltage tells the ECM to increase or decrease fuel delivery. Judging by the voltage tests I have performed I believe the higher voltages result in increased fuel delivery. - - - - and higher fuel delivery also results in more black smoke - - - - (like a mechanical 3208 when starting off). I also understand DD programs the ECU to be a little stingy on fuel in order to control smoke.
Back to my situation.
A few tests revealed the 12223861 "upgrade" sensor static output voltage (terminal B) about 1 volt with key on - motor not running. This indicates to me there is not a sufficient amount of fuel at low RPMs or boost.
Replaced he original unit and it static tested 2-2.1 volts.
So I ordered and installed a new 2 bar MAP. Static reading now at 2.34 volts. I haven't run it yet - other maintenance items are being addressed, but I am expecting good results. Test drive will take place tomorrow.
There is also some talk about building a small circuit board designed to trick the ECU into thinking it needs more fuel in the 0-5# boost range. Above 5# is supposed to be a non issue. Black smoke upon acceleration might be.
Please let me know how the #12219935 MAP sensor works out and I will let you know how my new 2-bar MAP works out. I am not 100% sure of the part # for my new MAP, but I believe it to be the first one of these 3
12247571 16009886 16040609

brhodes
05-28-2015, 01:40 PM
KC,
Look at the back of the sensor for the 3 digit number stamped into the metal.

3 digit numbers for identification stamped on rear of sensor:
1 Bar: 039, 460, 883, 876, 153
2 Bar: 886, 012, 539, 609, 701
3 Bar: 749, 861

MrBlueSky
05-28-2015, 03:20 PM
Barry,
Those numbers only seem to apply to the older, US made models. Newer imported ones, at least ones I've seen, don't have metal backs & many have no numbers stamped in them. Others have numbers, but not those listed. In fact, many don't even come in a labeled box. Guess you have to "trust" its what they are advertising. :)
Bill

KCSS
05-28-2015, 06:15 PM
Well - - - - “It’s a beautiful day in the neighborhood” - - - - at least in my neighborhood anyway. Just returned from my test run and have encouraging news. The new 2-bar MAP sensor is outperforming anything that has been in there since owning the coach. (5 years). If I had to put a value on it I would say 50% better than the original, and 200% better than the supposed 3-bar # 12223861 from ebay. (Disclaimer here - I could have gotten a bad 3-bar unit from ebay) :mad:.
Bottom line - coach accelerates better - boost pressure spools up almost immediately in first gear and does not drop off between shifts. I am a happy camper for the time being. :):):) From the very limited unscientific tests I have preformed I am heavily leaning toward a 2-bar as opposed the 3-bar unit based solely on static voltage readings (new 2-bar being the highest in my tests). This theory seems to be in accordance with John Wyatt’s understanding. (higher voltage = more fuel). As I said, I am a happy camper for the time being. That being said, I would still like to create a small circuit board devise with a variable resistor (trim pot) that would allow me to dial in a small voltage increase. I’m guessing somewhere around .2 volts would make a noticeable difference. Too much of an increase = too much fuel = black smoke. I suspect it will be a balancing act between acceleration, boost, and smoke. :( If I can come up with a working unit, it may need to be switched in and out on a as needed basis (like a propane injection system). This project is now on my TO DO list – in the low priority column. :rolleyes:
Ideas and suggestions welcomed.

rwoody
05-28-2015, 08:20 PM
well i used the 3 bar and read different per instructions but what ever works!@@@@@

awesome mine will make 28psi and 1000 egt on some hills if i dont back out!@Q

Randy Dupree
05-28-2015, 11:15 PM
Great job KC!
very good info.
But,a word of warning,don't forget that theres been many rearend gears broken in the 8v92 coachs.
Increasing the bottom end power may result in broken ring gears.

White Hat Guy
05-29-2015, 07:58 AM
Not sure what a "Map Sensor" is, even after reading these posts.

Somebody 'splain please.

"Fuel Gauge Re-set Tommy" (just so everybody knows how challenged I am.)

mpierce
05-29-2015, 08:17 AM
Not sure what a "Map Sensor" is, even after reading these posts.

Somebody 'splain please.

"Fuel Gauge Re-set Tommy" (just so everybody knows how challenged I am.)

I believe " manifold air pressure". It is a sensor that reads the air pressure in the clean air, after the turbo, and sends that reading to the computer, and the computer then knows how much fuel to use, based on how much air is available.

brhodes
05-29-2015, 08:47 AM
The logic module uses the manifold absolute pressure (MAP) sensor to determine the absolute pressure (not the relative to atmospheric pressure) of the air inside the intake manifold and the atmosphere (barometric pressure). This information is used to determine the density of the air entering the combustion chamber (in conjunction with the IAT (Intake Air temperature) sensor), which is used when calculating the proper air/fuel mixture for the engine, especially at WOT since the system is not in closed-loop at this time. It is also used to help adjust the IAC (Idle Air Control) motor during idle.
It uses a silicon wafer that is thinner in the center (0.001") than around the edges (0.045"), which causes it to act as a diaphragm. It is mounted with a perfect vacuum beneath the chip so that the air pressure from the other side flexes the chip. This flexing creates a change in resistance and the circuitry inside the sensor converts this to a voltage ranging from 0.02V to 4.94V when the output is pulled up towards 5V by the ECM (Electronic control module).
1 Bar MAP sensors are used on NA (naturally aspirated) vehicles.
2 Bar MAP Sensors are used on forced induction vehicles (Turbo & Supercharged). They can measure up to 2x the atmospheric pressure (29.4psi), so that means it can measure up to 14.7 psi boost (the atmosphere is 14.7 psi + 14.7psi from the turbo/supercharger).
3 Bar MAP sensors can measure up to 44.1psi, which translates to 29.7psi boost from a Turbo/supercharger.
They all share a common pinout, although the connector keying may be different:

Dieselbird01
05-29-2015, 09:09 AM
Not sure what a "Map Sensor" is, even after reading these posts.

Somebody 'splain please.

"Fuel Gauge Re-set Tommy" (just so everybody knows how challenged I am.)

Hi Tommy,

Another name for the MAP sensor is TBS or Turbo Boost Sensor. It just measures Turbo Boost pressure and sends a signal to the DDEC.

Randy Dupree
05-29-2015, 09:46 AM
The logic module uses the manifold absolute pressure (MAP) sensor to determine the absolute pressure (not the relative to atmospheric pressure) of the air inside the intake manifold and the atmosphere (barometric pressure). This information is used to determine the density of the air entering the combustion chamber (in conjunction with the IAT (Intake Air temperature) sensor), which is used when calculating the proper air/fuel mixture for the engine, especially at WOT since the system is not in closed-loop at this time. It is also used to help adjust the IAC (Idle Air Control) motor during idle.
It uses a silicon wafer that is thinner in the center (0.001") than around the edges (0.045"), which causes it to act as a diaphragm. It is mounted with a perfect vacuum beneath the chip so that the air pressure from the other side flexes the chip. This flexing creates a change in resistance and the circuitry inside the sensor converts this to a voltage ranging from 0.02V to 4.94V when the output is pulled up towards 5V by the ECM (Electronic control module).
1 Bar MAP sensors are used on NA (naturally aspirated) vehicles.
2 Bar MAP Sensors are used on forced induction vehicles (Turbo & Supercharged). They can measure up to 2x the atmospheric pressure (29.4psi), so that means it can measure up to 14.7 psi boost (the atmosphere is 14.7 psi + 14.7psi from the turbo/supercharger).
3 Bar MAP sensors can measure up to 44.1psi, which translates to 29.7psi boost from a Turbo/supercharger.
They all share a common pinout, although the connector keying may be different:

very nice explanation.
Thanks.

Randy Dupree
05-29-2015, 09:54 AM
On a powerstroke pickup i had once the MAP had a rubber line attaching it to the engine,the line was old and cracked,resulting in no reading at the MAP.

THis could happen on the 8V92 as well.

White Hat Guy
05-29-2015, 11:53 AM
OK experts

Thanks for the information and "tutorial". Now that I know (just enough to be dangerous) about the MAP Sensor, another question: How do you test or check them to make sure it is working right?

FYI I have good turbo boost and seemingly very good power and very little to no black smoke.

KCSS
05-29-2015, 12:35 PM
OK experts

Thanks for the information and "tutorial". Now that I know (just enough to be dangerous) about the MAP Sensor, another question: How do you test or check them to make sure it is working right?

FYI I have good turbo boost and seemingly very good power and very little to no black smoke.
All indications are you're MAP is doing its thing and just humming along beautifully ;););)
Testing them would require an accurate VOM. Testing range 0-5 VDC. Also a hand held vacuum pump hooked up to the MAP connector. There is a chart somewhere showing voltage to vacuum relationship. i.e. X amount of vacuum = X amount of voltage. Sorry I don't have that chart, but with a little research you should be able to come up with it ;););)
FYI - the guts within the MAP are very delicate and sensitive. (I dissected the bad one out of curiosity).
Don't fix it if it ain't broke :p:p:p

MrBlueSky
05-29-2015, 12:51 PM
Here are 2-bar charts (http://www.robietherobot.com/storm/mapsensor.htm)

Pressure-to-voltage relationship of stock GM Turbo MAP sensor (2 bar):
Manifold PSI (sea level) Output
14.31psi / 29.01psi --- 4.90V
14.00psi / 28.70psi --- 4.84V
13.00psi / 27.70psi --- 4.67V
12.00psi / 26.70psi --- 4.50V
11.00psi / 25.70psi --- 4.33V
10.00psi / 24.70psi --- 4.16V
9.00psi / 23.70psi --- 3.99V
8.00psi / 22.70psi --- 3.82V
6.00psi / 20.70psi --- 3.47V
4.00psi / 18.70psi --- 3.13V
2.00psi / 16.70psi --- 2.79V
0.00psi / 14.70psi --- 2.45V
5.00inHg / 12.24psi -- 2.03V
10.00inHg / 9.78psi -- 1.61V
15.00inHg / 7.33psi -- 1.19V
20.00inHg / 4.87psi -- 0.77V
25.00inHg / 2.41psi -- 0.35V
29.10inHg / 0.40psi -- 0.02V

MAP sensor output based on altitude (Ignition "ON" and engine stopped)
Altitude-Feet Voltage Range
0000-1000 ------ 3.8-5.5V
1000-2000 ------ 3.6-5.3V
2000-3000 ------ 3.5-5.1V
3000-4000 ------ 3.3-5.0V
4000-5000 ------ 3.2-4.8V
5000-6000 ------ 3.0-4.6V
6000-7000 ------ 2.9-4.5V
7000-8000 ------ 2.8-4.3V
8000-9000 ------ 2.6-4.2V
9000-10000 ----- 2.5-4.0V
Low altitude = High Pressure = High Voltage

KCSS
05-29-2015, 10:21 PM
Here are 2-bar charts (http://www.robietherobot.com/storm/mapsensor.htm)

Pressure-to-voltage relationship of stock GM Turbo MAP sensor (2 bar):
Manifold PSI (sea level) Output
14.31psi / 29.01psi --- 4.90V
14.00psi / 28.70psi --- 4.84V
13.00psi / 27.70psi --- 4.67V
12.00psi / 26.70psi --- 4.50V
11.00psi / 25.70psi --- 4.33V
10.00psi / 24.70psi --- 4.16V
9.00psi / 23.70psi --- 3.99V
8.00psi / 22.70psi --- 3.82V
6.00psi / 20.70psi --- 3.47V
4.00psi / 18.70psi --- 3.13V
2.00psi / 16.70psi --- 2.79V
0.00psi / 14.70psi --- 2.45V
5.00inHg / 12.24psi -- 2.03V
10.00inHg / 9.78psi -- 1.61V
15.00inHg / 7.33psi -- 1.19V
20.00inHg / 4.87psi -- 0.77V
25.00inHg / 2.41psi -- 0.35V
29.10inHg / 0.40psi -- 0.02V

MAP sensor output based on altitude (Ignition "ON" and engine stopped)
Altitude-Feet Voltage Range
0000-1000 ------ 3.8-5.5V
1000-2000 ------ 3.6-5.3V
2000-3000 ------ 3.5-5.1V
3000-4000 ------ 3.3-5.0V
4000-5000 ------ 3.2-4.8V
5000-6000 ------ 3.0-4.6V
6000-7000 ------ 2.9-4.5V
7000-8000 ------ 2.8-4.3V
8000-9000 ------ 2.6-4.2V
9000-10000 ----- 2.5-4.0V
Low altitude = High Pressure = High Voltage

Oh Boy Oh Boy ;) I say I say ;) You made my day :):):)
Can't wait to play mad scientist - just like making a A-Bomb - I'm gonna control the world :D:D:D

I knew I had seen that chart at one time - but could not remember where - - - - THANX :):):)