Map Sensor Issues #55573248 Please help

[Brocal]

Hi Guys,

I bought Hp tuners for my trans am some years back(2000 Ls1). I have since gotten a new project car. I've dropped in a custom built LS3 which has MAP Sensor #55573248 in the intake. I've scoured the web looking for MAP sensor calibration data and all I could find was .5-4.5V and 0-130 Kpa. I would think this should work. I've driven the car a bit and my MAP readings seem to be off. Sitting in the garage, my atmospheric pressure should read around 79Kpa( I live at 6700 ft elevation) and the Map reads 86Kpa. Also, when I back off the throttle the Kpa reads 0 and my ECU cuts fuel completely thinking I've got no air. Since this was a total custom build I'm running Holley terminator software for this particular build. Do i have the wrong calibration data or is there something I should be checking? I've gotten zero help in the Holley forum and I was hoping this forum would provide a bit more technical help.

I really hope someone has dealt with this issue before.

Thanks guys

[Ben Charles]

That’s such a small change in map I wouldn’t worry, tune the VE on the Holley and be happy with it

[Brocal]

It would seem livable but my concern is that the deceleration or high vacuum portion of my readings are way off thus creating havoc to my base fuel map tune. I don't like that the computer is cutting fuel for me without reason. I have a minimum injector pulse width set to 1 msec and it isn't actually providing that. There's also a fuel cut function I could enable or disable. I have it disabled currently. Does anyone else out there have 0 Kpa readings on deceleration? 0-30 Kpa area seems highly suspect to me.

[blindsquirrel]

https://www.rockauto.com/en/partsearch/

Click on any of the blue part numbers and it will show the applications... pick an application that's likely to be found in the repository, say 2010-2015 Camaro. Go to the listings for one of those years and see which engine lists that part number - in the case of your 55573248, that would be a LS3/L99. Then go find a tune file from a car from one of those years with that engine and look up what it uses for linear/offset.

55573248 is 128.13/-0.31.

I would rig up a voltmeter onto the MAP signal wire and see what the actual voltage is when it's displaying 0kPa. That's not really a plausible MAP reading, so I'd be suspecting an intermittent connection issue.

[Brocal]

Dumb question coming. I don't have the Hp tuners software downloaded on my current computer yet. Is the repository only accessed through the software or on this forum?

Is that Kpa reading from 0-5V?

Sorry and thank you for that response. I really appreciate it.

[blindsquirrel]

https://www.hptuners.com/my-account/tunerepository/

GM uses 0-5v, MAPs are linear so should be simple to figure the mV per kPa if you need 0.5-4.5v.

[Brocal]

I can actually change it to 0-5V. Thank you this has been super helpful!

I've been digging around my hp tuners stuff and searching for my application key. Since I bought this a few years back its proving difficult to dig up all of my necessary info. Looks like my account has been forgotten on the website.