Manifold Absolute Pressure sensor measures the intake manifold pressure and sends a frequency signal to the EEC-IV module
MANIFOLD ABSOLUTE PRESSURE SENSORS (MAP)
WHAT THEY DO
A Manifold Absolute Pressure Sensor (MAP) Sensor monitors the changes in the intake manifold or vacuum pressure during various engine operating loads and sends a corresponding signal to the automobile’s computer.
Since the S and Si hae different engine displacment I'll asume the MAP sensor for the Si is designed to read/accept higher levels of intake pressure for the increased size/HP
i checked the volts and I'm getting 12v, 12v, and a ground.
What the hell happened?
PS. I am in "limp mode" and throwing the CEL any ideas how to fix?
I'm not sure how your checking your MAP sensor but you should be reading no more than 5 volts.
Do this, run a cel code check, if your getting a code 3 or a code 5, either of those mean it's your Map sensor, 3 is for electrical problem 5 is for mechanical problem.
Then come back and tell me what happens
you should be testing the red/white terminal on the connection right beside the MAP sensor mounted on your firewall, use the car body as a ground.
yeh, you should be getting five volts at two of the pins and a good groung at the third. i've got a similar problem, except i have no 5v on my middle (blue/white) pin.
I'm not home right now. Sounds like you got an electrical problem. I need you to run another voltage test on the red/white and then the blue/white connectors with a good ground. tell me wat voltage your reading on each set of colored connectors and I'll give you a next steps solution as soon as I get home
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Last edited by Machine Head; 06-26-2002 at 04:31 PM.
Well he hooked it up to a scantool and we got 12v 5v ground the 12v one stayed at 47-49hg with the car on and the car off The only code it is throwing now is 3. The car was originally a f22 96' and I put in a 94 H23. I bought the skunk 2 conversion harness with a ODB I P14. I am however using the original engine harness from the 96 f22. I got the scimatics and all the wires are they are supposed to be. I was going to run the map sensor wires directly to the ECU and see if that works, what do you think? I am getting really tired of this thing and have tried everything I know even had another si to look at and check and the wires are they are supposed to be.
Originally posted by sik96prelude Well he hooked it up to a scantool and we got 12v 5v ground the 12v one stayed at 47-49hg with the car on and the car off The only code it is throwing now is 3. The car was originally a f22 96' and I put in a 94 H23. I bought the skunk 2 conversion harness with a ODB I P14. I am however using the original engine harness from the 96 f22. I got the scimatics and all the wires are they are supposed to be. I was going to run the map sensor wires directly to the ECU and see if that works, what do you think? I am getting really tired of this thing and have tried everything I know even had another si to look at and check and the wires are they are supposed to be.
actually you are on the right track, if your not getting a 5volt reading from the red and white, then you need to run a voltage test on the f22 harness, however I'm not really sure which PINS you should be testing. My helms is for h22/h23 only. helms tells me you should be measuring the voltage between D19 and D21 but it might be diff for your F22. if the harness is still giving you a reading of 12 volts then you know it could be that and you need to wire the sensor directly to the ECU as a next step
hey, machine head, i was wondering if you might be able to give me some insight. looks like you know something about this problem. my blue/white wire has no voltage on it. (93 S w/ 94 VTEC engine). when i pulled off the cap for the bus terminal, i read the wire that feeds the blue/white when the cap is on (orange plug looking thing in driver's right side of foot well. the cap takes power from some of the wires, and distributes it to more wires). the problem is, when i put the cap back on, i read the same wire, and the voltage disappears. i think i have a short downstream somewhere, but i don't know where. if this confused you, i can refer you to some of the Helm manual (i also have another book with schematics, so i may not be able to get you all the info. if you can (want to) let me know, if not, that's cool.
Originally posted by sik96prelude One more question will my car run right without the silienoid (sp) to the second set of butterfly's on the manifold?
def not, without that soliniod your secondary runners will either always be open ( total loss of low end power) or always closed (total lack of high end power)
hmm... i threw a MAP code..but mine was cuz my Vafc connection came apart, and my motor ran like ass till i fixed it..do u by chance have a SAFC? just curious...if not cut the wire your getting 12v too, connect a wire to it, and run it directly to the ecu...that will tell you where your problem lies...
ZIG you lost me when you went from the blue/white wire to the orange bus.
Are you testing the voltage from under the hood when you say blue white or have you done all that and started testing voltage from the harness or ECU?
Helms refernces would be nice. I'm no genius but I'll try and help
i'm shooting the harness, now. i shot from the connector to the inside of the car. i didn't see any diagrams in the service manual, but i have an electrical manual also. if you have that, it would be a lot easier to point out. it shows the whole wire including all the connections involved. it also shows pictures of the location of each connector. if you had that book it would help a lot
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