Nige
Senior Member
I've seen cases before where sensors designed to read quite high pressures, like the IAP which IIRC is designed for pressures up to 10k psi, can be wildly inaccurate at the low end of the scale because it's outside their designed "comfort zone". A particular P/N of pressure sensor on mining equipment autolube system springs to mind but there were others as well. Could never get them to read zero or anywhere close to it when there was no pressure in the line.I can’t explain it but I’ll report it. I went back today and worked on the engine. I checked My wiring to the sensor and it all checked out. I remover the sensor and put a test fitting in to check what my actual iap pressure was. With the sensor out and unplugged the iap pressure was well over 3000. Hmm. I plugged in the sensor and and tried again. This time it read around 900. thought it was weird so I did it again to make sure I hadn’t finally lost my mind and it did the same. so I reinstalled the sensor and put the pressure fitting in the other head. I hit the key and I’ll be damned it started and ran. ET still read that I had 250 psi with the engine off but it did read pressure while it was running. All I can think is that i may have a broken wire somewhere and with all my screwing around I made a contact somehow. We’ll see What happens. The tub needs a pile of work and the customer just wanted to see if I could get it running.
Apologies for steering you wrong regarding the pump drive but when you said the engine just quit it was the first thought that sprung into my head.