PFS PMS ecu, keypad readings....
 

How accurate is the reading from the PFS PMS using keypad?

The reason i'm asking this question is When i look at the MP (boost) it shows at idle like -18,-19. But my autometer gauges show 15 and 16. Which is more correct. I know ECU get's reading from map sensor, and i tapped the gauges in to the UIM on that nipple next to bov hose.

Thanks a lot.

Amel

The Autometer guages are within +\- 1 %. I have a PMS too and it reads the same thing. I was also thinking that my guage was bad and took one out of my other car and it was the same ( had both plumed in together ). I would belive that the computer is wrong.

I got an Autometer that was 2psi off at zero while still in the wrapper. 2psi/60 "units" range (not entirely correct since vacuum is a different unit) = 1/30 = 0.03 = 3%. I still have an HKS that is at least 2psi off.

I have numerious other vac/pressure diagnostic gauges and mechanical stuff all reads a little different for the same input. Maybe Autometer quotes +/- 1% in their specs, but I would tend to believe a solid-state sensors that doesn't get worn out over time. Unless that gauge is calibrated to a proper known good, it's just a rough indicator. Also keep in mind that if you don't have exactly the same boost source there is a possibility that the intake charge has changed temperature and will indicate higher/lower.

I'd go with the map sensor since that's what you are using to control the fuel delivery. :)

I also have a PMS and your right that when its in vacum at idle it records -19/-20 but note my boost setting are pri 15, sec 15. When I`m in boost both instruments (gauge/PMS) read 15 lbs on WOT...I`ll trust the MAP sensor.

Andre