not sure where to put this but ill give it a shot. so i was asked to look over this TT 347 trans am. now when i looked at it somehow someone uploaded a 3 bar tune into it using 2000 vin but car is 01. well i get a copy of the stock NA tune and then write all of the tune into it. well made all the changes i needed to make it SD. well heres the weird parts....car was converted over to return style. it has dual 255s intank. magnafuel regulator....it has 60# injectors.. heres the weird part, when the 00 bin was uploaded it would start but had all kinds or poor throttle response and etc. tune was properly setup as SD. ok so i went to upload the tune and it wouldnt fire...after tracking down the issue, for some reason with the 01 bin it wouldnt fire unless i set the injectors up for stockers.....ok took it for a spin and i wouldnt see over 10 kpa on the map. well for ***** and giggles we dropped the injector table down to 26s and the fuel trims fell right into place, car idle smoothly and had alot better lower rpm throttle response. and highest i seen was 18 kpa on the map

now could the problem lie being it has a 3bar map sensor and the tune is a 1bar map? or does this sound like a fuel issue? the fuel gauge wasnt hooked up at this moment but it has been hooked up and varified of 58psi at idle

any insite would be a bonus

 

Did they switch to an 00 PCM? Is this EFI Live?

 

its HP, no its a 01 pcm thta someone didnt know what they were doing and just did write entire along with enabling 3bar for the OS. it was popping crank relearn and other issues. it now has the proper vin and OS for the car

 

Yes, this is very likely the problem. Figure that a 3 bar map reads roughly up to 285kPa on the same 0-5V signal that a 1 bar map reads up to 105kPa... So, if you're running a stock OS with the 3 bar signal, then the MAP reading is approximately 1/3 of actual. This causes injector pulse widths to be much much lower.
By reducing the injector flow rate, you've in essence told the PCM that it needs to hold the injectors open longer to achieve the same amount of fuel... and stock 26#ers are right near 1/3 of the size of the Mototrons (63.2# at 43.5psi, 72.3# at 58psi).

 

so once enabled as a 3bar tune then it shoudl be fine with the calbration for the 60s?

thanks

 

Yep. I totally missed the 3 bar sensor and 1 bar tune bit -- rough day yesterday

 

Also make sure that you setup the custom PID for a 3bar sensor otherwise it will continue reading incorrectly, as far as the injectors?? I am not sure. If the tune is enabled as a 1bar OS then I would think setting it to the correct 3barOS would straighten out the fueling issue. As mentioned above the PCM is reading the signal as a 1bar so the reading is a very low KPA.

 

I was reading Quik's first post thinking as I was getting to the end, "I wonder if 26 is just the right ratio to make it all work good enough?" LOL Nice, that could of been a horror of a problem for some. Long story short,an analogy would be like putting a WBO2 in your NBO2 spot.