Weird 2 bar MAP sensor readings
Weird 2 bar MAP sensor readings Finally was able to upload my base tune to the stock 5.3 PCM. Its a stock 5.3 with 60lb bosch injectors (actually 72lb at 58psi), LS6 blue springs and a torquestorm supercharger hopefully making 10-12psi.
Running a HPT 2bar OS and using a cheap 2bar MAP sensor off ebay. Decided to test the sensor at different KPA (15" to 0" for now). I wanted to verify the voltages before I get close to starting and already ordered an AC delco replacement 2 bar MAP sensor.
I also tested the stock GM MAP sensor to see what voltages its putting out and got some weird numbers. I figure since the OS has changed its skewing the 1bar stock sensor?
1bar GM 2bar Cheap Aftermarket
0" atmosphere = 4.44v 0" = 4.79v
5" = 4.44v 5" = 3.82v
10" = 4.44v 10" = 2.89v
15" = 4.44v 15" = 1.94v
However when I looked up voltages for 1,2,3 bar MAP sensors I see voltages that should be about 2.25 - 2.5v at 14.5ish psi which should be atmospheric pressure.
When I had HPT VCM scanner with the cheap 2bar sensor in the intake it showed 0.0psi in the scanner... which is right since its at atmospheric pressure.
Am I doing this wrong?
Running a HPT 2bar OS and using a cheap 2bar MAP sensor off ebay. Decided to test the sensor at different KPA (15" to 0" for now). I wanted to verify the voltages before I get close to starting and already ordered an AC delco replacement 2 bar MAP sensor.
I also tested the stock GM MAP sensor to see what voltages its putting out and got some weird numbers. I figure since the OS has changed its skewing the 1bar stock sensor?
1bar GM 2bar Cheap Aftermarket
0" atmosphere = 4.44v 0" = 4.79v
5" = 4.44v 5" = 3.82v
10" = 4.44v 10" = 2.89v
15" = 4.44v 15" = 1.94v
However when I looked up voltages for 1,2,3 bar MAP sensors I see voltages that should be about 2.25 - 2.5v at 14.5ish psi which should be atmospheric pressure.
When I had HPT VCM scanner with the cheap 2bar sensor in the intake it showed 0.0psi in the scanner... which is right since its at atmospheric pressure.
Am I doing this wrong?
Yes, I got the cheap one just to test it and see how they actually compare. I've already ordered a AC Delco GM MAP sensor but it's on back order.
But with a real 2bar MAP sensor I should be seeing the correct 2.25-2.5v at atmospheric pressure right? Like it sitting in/out of the intake and the engine being off?
But with a real 2bar MAP sensor I should be seeing the correct 2.25-2.5v at atmospheric pressure right? Like it sitting in/out of the intake and the engine being off?
Put your stock MAP in with stock map sensor settings in the tune and see what it reads with the key on engine off. With a good 2 bar map sensor and the right scaler and offset it will read the same thing as your stock one.
I believe the tune settings I used are
200 with a 10.33 scaler...
Do you recommend the AC Delco version or the actual GM version? Their is like a $20 difference in price.
Decided to eat the extra $20. In the long run its prob a wise investment and could possibly avoid tuning headaches and hopefully last longer.
GM performance 2 bar sensor ordered! GM 12615136
http://www.summitracing.com/parts/nal-12615136
GM performance 2 bar sensor ordered! GM 12615136
http://www.summitracing.com/parts/nal-12615136
Got my new sensor the other day.
Side note, do not buy GM performance part MAP sensors. I bought the AC Delco version for 47$ but was on back order for 2 weeks minimum, GM performance sensor was in stock for $68 so I said screw it and had them charge the difference. Package arrived and in the box was an AC Delco sensor box lol... Same part number and everything. I called summit and was like WTF... That's ridiculous to sell the same sensor for $20 more and not even change the box lol. The lady said AC Delco makes the sensors for GM so they are the same. I made them refund me the difference so it all worked out but I thought it was bullshit. So save your money and buy AC Delco vs GM brand... Same quality and your just paying for the name.
Now I put it on and got some new voltage readings!
AC Delco
0" = 2.34v
5" = 1.85v
10" = 1.42v
15" = 1.01v
That's a huge difference compared to the cheap eBay sensor!
eBay
0"= 4.75v
5" = 3.82v
10" = 2.89v
15" = 1.94v
Side note, do not buy GM performance part MAP sensors. I bought the AC Delco version for 47$ but was on back order for 2 weeks minimum, GM performance sensor was in stock for $68 so I said screw it and had them charge the difference. Package arrived and in the box was an AC Delco sensor box lol... Same part number and everything. I called summit and was like WTF... That's ridiculous to sell the same sensor for $20 more and not even change the box lol. The lady said AC Delco makes the sensors for GM so they are the same. I made them refund me the difference so it all worked out but I thought it was bullshit. So save your money and buy AC Delco vs GM brand... Same quality and your just paying for the name.
Now I put it on and got some new voltage readings!
AC Delco
0" = 2.34v
5" = 1.85v
10" = 1.42v
15" = 1.01v
That's a huge difference compared to the cheap eBay sensor!
eBay
0"= 4.75v
5" = 3.82v
10" = 2.89v
15" = 1.94v
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Verdad Gallardo No these are in vacuum inHg as that's all I can test for. I'm only using a mitivac to get vacuum resolution voltages at the moment. In order for me to get boosted numbers I'd have to whip out the compressor and dial down the regulator and hook up a hodge podge of hoses and gauges to test it. But at 0" or atmosphere which should be 14.7psi the new AAC Delco gauge is showing that voltage I stated above. So idk if that's correct but it seems about right as it would be a full sweep from 0-5v and 2.5v being in the middle which would be 14.7psi/atmospheric pressure.