2003 Chevy Avalanche 5 3 Misfire, Restricted Exhaust (Part 2)

www.scannerdanner.com/scannerdanner-prem...-exhaust-part-2.html

I'm still finding interpreting the MAP pid a bit confusing. When it's up on the screen, the scale is inHg, which looks like a vacuum reading on my handheld vacuum gauge. However, it seems like you have to do some math to get the actual reading, like everything is inverted or something.

Anyone have a good explanation of how to read this?

Your MAP pid is in inHg? What scantool do you use. Maybe you can change that. I agree on the gauge. I also have gauges with this unit and sometimes I have to use a converter. Hell we don't even use psi here. It's all metric

I've never worked on a car with a MAP, I'm just going off of what I saw on the SD video referenced above.

If I remember correctly, you subtract the MAP reading from the BARO reading to get the manifold vacuum reading. I've got data from an '03 Blazer for comparison.

www.scanshare.io/share/heEVuXVVWkiYjDa8EEhdSQ



At WOT, the BARO is 28.6 inHg, and the MAP is around 27 inHg. That'd translate to around 1 inHg vacuum, pretty normal for a WOT run. Earlier in the capture, the engine is idling with a BARO of 29.2 and a MAP of 13.2. That works out to 16 inHg, which isn't surprising considering this Blazer had a dead misfire. :lol:

Thanks! You find that scanshare site useful?

SailorBob wrote: Thanks! You find that scanshare site useful?

No problem. ScanShare is fantastic for stuff like this, networking and such. It also makes it possible to view scan data captures on my phone and at work.

Case in point, diagnosing a tough one last week. I've got some known good captures at home, but work doesn't have the Snap-On software (ShopStream Connect) installed anywhere. Upload to ScanShare and boom, easy viewing at work.