Hello,
I was wondering if any one knew of a after market boost pressure sensor for a 87 TII.Mine is bad and i know stock will be big $$$$$$$.I would be better of getting something better for my money.Can anyone help me out.

Thanks
John Turner

 

i hear you man, i went to the old mazda dealership and they wanted like $344
i think your best bet would be to find a used one.
p.s. are you shure it needs to be replaced? have you measured its outputs and crossreferenced them? mine sets the engine light off still but they sensor outputs look nice so i need to track down some wires to the ecu or ground or somethin

 

I checked it all out with 3.9 in. hg applied to the vac its volt output is 2.0 is is supposed to be at least 3.5-4.5

 

Hey cozmic,

Mine checked out about the same. Don't pitch it just yet, though. If HAILERS gets on, he can tell you the voltage readings he got on his. Maybe the manual specs aren't all that hard and fast for the boost/pressure sensor.

good luck, dude

Gregg

 

Factory service manual quotes 2.0 to 2.5 for 3.9 inches HG for a Turbo, it is 2.5-3.5 for an NA, my sensor is at around 2.0 volts for that reading, and my TII runs normally.

Irv, Keith's dad

 

Hey COSMIC.....can you read the numbers on the top of the sensor. Something like N227 I believe goes on a N/A. At work and can't check, but I was looking at my N/A Sunday and I believe that was what was on it. Give us the number you have and we can determine if you have the wrong sensor for your car. Maybe you can sell it if its the wrong one.

 

The part # on it is N318.

Thank Hailer

 

Well COSMIC, I had good intentions, but......when I got home I saw this post and ran to the turbo, and things went to hell in a hand basket. Part of one number is left and it MIGHT have been a 8. The I've got another number E1T10771 and another 6604. So, its inconclusive. Might call a dealer and ask for the number, or I saw a fella last nite on this forum that offered a download of the fisch for RX7'S. OR, even better someone on this forum with a turbo can gingerly waltz out to his car and note the number on his.
In case it was not too clear, on that sensor on my turbo, there were three numbers. On the N/A there was just the N327.

 

Hey cosmikbluTII. Your boost guage number, N318, is the correct one for a TII. Your output for 3.9 inches/Hg is 2.0 volts, which is within specifications. Now, why is it exactly that you want to replace the sensor??? I don't understand.

Irv, Keith's dad

 

Oooops. Your right Irv. Nothing wrong with the sensor.

 

I want to replace it b/c my car barely boosts

 

And my manual says 3.5-4.5 volts.WHat manual are you looking in?Iam no saying your wrong but just want to see if you got a better service manual.

 

OK, John, when you say your car "barely boosts", do you mean your car actually for true really barely boosts, or do you mean your car boosts like a ****' but your guage indicates it barely boosts? Please clarify this, it is very important, since on your car's boost is not in any way, shape, or form electronically controlled. However, if boost is not correctly sensed, your engine may go kablooey!

Irv, Keith's dad

 

Why don't you replace it with a new mechanical boost gauge isntead? Only like $25-$45 for one.

 

I am getting my information from page 78 of the 88 Mazda Factory Service Manual, section 4B. If you wish, you may check the article "Do it yourself fuel cut defensor" on the website teamfc3s.org. It contains a graph of boost vs voltage, and 3.5 to 4.5 volts is above fuel cut (in excess of 8PSI boost)! Take my word for it, John, your boost sensor is NOT reading incorrectly! Perhaps you are confusing that with the atmospheric pressure sensor. It just so happens that the spec. for this sensor IS 3.5 - 4.5 volts, however, this sensor is located under the passenger floor carpet/plate near the ECU, and is only used to reference current atmospheric pressure as a baseline for the ECU (it has no vacuum hose attached). At any rate, please answer my above post so we can get to the task of fixing your boost problem. Have a good day!

Irv, Keith's dad

 

Thats odd what Irv said about the atmospheric sensor being on the floor under the carpet etc. Mine is under the dash, passengers side, far right. Picky, picky, picky. I know.

 

Cozmik....I doubt your sensor is bad but I have one that is known to be good if you need it.

You can email me at toddkageals@***.net

Todd

 

her Irv or Hailer, can you tell me what you think of these
mmHg -Voltage
0-3.83
100-3.30
200-2.70
300-2.20
400-1.72
500-1.17
600-0.77
its for an 89NA, i think the outputs look good, but it keeps setting my engine code off. usually only when its cold out, and under throttle
sorry, i know ive bothered you about this before, but i guess i'll have to find a bad wire or something

edit:
also the brown/white is pos. and has 5.01v
and the Brown/black ground has 12.15v
the output wire to the ecu is green/yellow

 

a nine my boost pressure senor wasnt bad om my TII i started this post with.It was a bad grond to my motor.I bolted the ground back up and presto i got boost .boost is a beautiful

Thanks everone for the help the help
CozmikbluTII

 

Really and truly ought to leave this one alone, but: Reading from the 1987 factory service manual, the pressure sensor for a TurboII, should have a voltage reading of 2.0~2.4V at 100 mmHg (3.9 in Hg). Very similar to what my 1987 TurboII reads. Car be runnin plenty good fine, boostin 10piss I.