It started out as a code 33. I repaired a broken connector now i'm getting 34 and no 33. I know it's Manifold Absolute Pressure (MAP) sensor circuit (signal voltage low, high vacuum). I tested the wires and it's getting 5 volts.

I have datamaster, so i can get some more figures if needed. What should i be checking?

 

5V would be the reading between the gray wire (5V reference from the PCM) and the black wire (ground from the PCM). That just proves the PCM is supplying the correct reference voltage. You need to measure the voltage between the light green wire (signal out of MAP sensor) and the black wire. At idle, that reading should be about 1.5V. The code sets when MAP reading drops below 14kPA, or about 0.4V.

In Datamaster, look at the MAP reading. At idle, it should be about 10" HG or 33kPa (info that is in my online scanner guide).

 

I just checked out your site and there is a lot of good stuff, thanks for the time you put in it. I have a cc306 so is there a ratio i should be looking for besides

Bar / 3 = map ?

 

And when i check the green and black am i checking it while it is connected to the map? If yes then do i just peel back some of the wire to get the reading?

My bar is 98.2 and my map is reading between 62 and 64 kpa, but i have a cc306

 

I like to stick a straight pin through the insulation, or down into the connector so it contacts the pins, rather than peel back the insulation. Yes -engine running, MAP plugged in. You need to measure the signal voltage.

With the 306 you will probably see 60kPa at idle. That would be about 2.7V

 

Code went away after i repaired my knock sensor malf 43. For the 1st time in 2 years i don't have a check engine light. My car is running a lot better, but now there is a miss in it that gets pretty bad at wot. I started out with 8 codes and i'm down to a 68 a/c relay shorted. I'm pretty sure that only affects the ac.

Any thoughts on where i should go from here? check the coil, wires, plugs? OR is there something i can find out by looking at the datamaster?

 

Update, I know it's not the ignition. It was detonating and popping like crazy, so pulled over and unplugged my o2 and the car ran fine. Therefore i think it has something to do with a sensor?

 

Or stick a small sharp pin directly through the wire

 

anyone?

 

Got to be ralated to closed loop. O2 sensor(s) would seem logical. A scan would tell you what's happening to the long term fuel corrections in closed loop. Run a log under the conditions that produce the misfires, and either post it on an FTP site, or send it to someone who is willing to look at it. If you post the files as both .uni (DataMaster) and .csv (export as) anyone can look at the files, whether they have DataMaster or not.

I'd offer, but I am so backed up with files to look at for people that I can't get to them for about 2 weeks.

 

swap out the o2.. sounds like its bad and dumping fuel