I have a '97 F-250 in the shop right now that cranks over but will not start. I scanned it for codes and found two codes for the CMP sensor, which I replaced but still no start. The scanner shows about 150 RPM while cranking so the CMP appears to be generating a signal. When I press the schrader valve in on the fuel filter housing while cranking it pumps out a stream of clear fuel, no air bubbles. The scanner shows IPR pressure at 3,500 psi while cranking, which from what I've read is way too high. I've connected a pressure gauge to both heads and verified the pressure spikes to over 3,000 psi while cranking. I've tried disconnecting the ICP sensor but it still won't start. The injector pulse width is showing about 1.8 ms while cranking (going by memory on this number, it may not be exact.)
One thing I've noticed: if I leave it set for a minute or so, then start cranking it will attempt to start and run for about one second, then stalls and refuses to fire again. I've watched the scanner while it does this and it looks like once the IPR pressure jumps over 500 psi it stops firing.
I'm assuming this means the IPR is stuck? I've tried a different solenoid on it too but I haven't pulled the valve out yet. Am I heading the right direction by replacing the IPR?
One thing I've noticed: if I leave it set for a minute or so, then start cranking it will attempt to start and run for about one second, then stalls and refuses to fire again. I've watched the scanner while it does this and it looks like once the IPR pressure jumps over 500 psi it stops firing.
I'm assuming this means the IPR is stuck? I've tried a different solenoid on it too but I haven't pulled the valve out yet. Am I heading the right direction by replacing the IPR?