Thread: Petrol in a diesel ford rager

Originally Posted by No.3

Nope, engine stop is achieved by the fuel pressure modulation valve (what us not-Bosch mortals call a suction control valve) going to full open and dumping rail pressure back to the tank... This was the critter that stuffed my Ranger up - it was not opening correctly to release pressure off the common rail so that when you hit the top of a hill and throttle off, the common rail pressure was being told to drop back by the ECU (modulation valve commanded to open) but the valve wasn't opening - meaning the commanded pressure and actual pressure were different enough to trigger a limp mode alarm (fuel pressure out of specification).

The vehicle didn't have the usual symptoms of fuel injection failure (the issue I had was too much common rail pressure), which made us look a lot further into it spending a lot of time with a datalogger. Biggest issue is with the datalogger on, it played ball and behaved. Take the datalogger off, and it would trip an alarm and go into limp mode within minutes the stupid Ford thing...

Yeah I didn't think the rail being pressurised all the time sounded right.