Fast 5 bar map sensor

novi2000 · #1 (**permalink**) 03-07-2010, 11:52 PM

I have the Fast 5 bar map sensor and I notice that when I start the car and it is at idle my KPA reads 28. Is this an indication that the calibration is off?

Thx

SoCal · #2 (**permalink**) 03-08-2010, 10:50 AM

Not necessarily. Have you ever noticed what your idle vacuum was with a gauge or a different sensor? Maybe that is where your engine idles. Check out your MAP reading with key-on, engine off. That should be right around 100 kPa. That is a quick and easy way to make sure you aren't using a calibration from a different range sensor.

Also, you could check out section "6.5.2 MAP Calibration" in the helpfile (from inside CCom select Help/Index). It discusses MAP sensor calibrations.

TurboNova · #3 (**permalink**) 03-08-2010, 01:10 PM

Are you really going to run more than 30 pounds of boost?

novi2000 · #4 (**permalink**) 03-08-2010, 01:15 PM

Already doing it I have a 2003 cobra compound boost setup.

TurboNova · #5 (**permalink**) 03-08-2010, 03:14 PM

cool, what kind of power does it make? Is this the Hellion Kit?

novi2000 · #6 (**permalink**) 03-08-2010, 08:54 PM

It is the Hellion kit I judt dynoed it at 932 rwhp on E85. I am trying to get the flex fuel config to work and that is not going so well. the E85 tune is perfect but when I put 93 octane the cars runs really bad.

TurboNova · #7 (**permalink**) 03-08-2010, 09:43 PM

Keep me posted on the E85 sensor, I am about to do the same thing on my Nova wagon.

novi2000 · #8 (**permalink**) 03-08-2010, 11:30 PM

Will do, I was expecting that when I changed form E85 to 93 octane the a/f ratio would stay somewhat constant and that is not what is going on the a/f is off by almost 2 full points from the target a/f at idle on 93 octane.

TurboNova · #9 (**permalink**) 03-08-2010, 11:46 PM

Originally Posted by novi2000

Will do, I was expecting that when I changed form E85 to 93 octane the a/f ratio would stay somewhat constant and that is not what is going on the a/f is off by almost 2 full points from the target a/f at idle on 93 octane.

Are you running it in closed loop? and how much are you letting it correct?

The E85 is quite different than pump or race fuel. I am not suprised that it has changed that much.

novi2000 · #10 (**permalink**) 03-09-2010, 12:17 AM

I am running closed loop at idle i only have 5% correction set based on my E85 tune it only corrected to 3 %. With the switch to 93 I bumped the - 02 correction to 10% and it is still off so ext would be -25%. I would expect that once you get a base line tune that and get your 02 correction set properly and the a/f ratio once you switch fuels the GM sensor should notify the ECU of the new Fuel Energy fuel constant and the appropriate changes to the tune would be made to maintain the tune. My thoughts if you have to rely on the O2 correction to pull the tune in range I don't see the purpose of the GM flex fuel sensor other than changing the Fuel Energy Constant? For that it seems to make more sense to get the thumb wheel make 2 tunes E85 and 93 octane, set the o2 correction to 15-25% to account for E70 - E85 blend changes.