MAP sensor

[xiaogary]

I am not running boost (may be using ROTREX C30-74 supercharger or TD04H in the near future running 1-1.5 bar boost since I am already on forged con rods and forged pistons,only need to change to low compression 8.8:1 pistons from wiseco, but afraid stock F16 gear box cannot take the increase in torque).

Seems like the current MAP sensor go haywire (crazy) when under heavy load.

[aveodude]

This is the one I am talking about.

http://cgi.ebay.com/ebaymotors/GM-3-...Q5fAccessories

The reason I am thinking of buying is because, at the last tuning session. When my tuner is trying to keep the AFR or lamda sensor at 13.5 at above 4k rpm. He mention something like my sensors is not very wide band resulting in sometime the ECU kicks in and interupt the mapping when he go above 4k rpm. So he can maintain a good 13.5 befor 4k rpm. But after 4k rpm, he is unable to get the best tuning result due to the "unstable" sensor he said. One step he change above or below, it goes crazy and the dyno lamda sensor shoot up and down instead of mantain a beautiful straight line at 13.5. It is now like a bit zig zag between 13.2-13.7 for rpm above 4k. I think he mentioned engine loading sensor or something like this. Which I duno what he is talking, I guess is either O2 sensor or MAP sensor since my aveo is without a MAF.

Does a car goes above 14.7psi at manifold? I have seen only 14.5 or 14.6 psi at the Scangauge from my OBD II while driving. If I change to 2 bar or 3 bar sensor, is it possible to detect some boost of maybe 1-2 psi?

Either there is a translation error, you are mis understanding your tuner, or he is mis informed. The only reason for you needing a larger MAP is because you are boosting it more than the stock sensor can read. Since you are in VAC all the time, a larger one will do nothing to your situation.
What I would look for is knock above 4K rpms.

The only reason you should see 14.7 psi at the manifold is if you are in a boosted car. Very very few N/A car will ever get out of VAC and those very few that do will only develop 1-2 psi, not 14.7. I think that you are confusing 14.7psi for 14.7afr which is stoich

[mralx152]

How do we take the stock one out and put it in a new intake.? Im stuck

[rrb6699]

I'm getting a P0420 code. it could be the MAP sensor. I'd like to find, test and clean it at least. also, my gas mileage is not good and has dropped.

the check engine light came on while driving so I checked the code. this is the only code so if I'm getting extra air into the intake somewhere. I'd like to know where to look for leaks.