Hi to the group.We own a 1990 Rexhall motor home with a Ford EFI 460 engine. It has run like a top for years. Last fall it began to backfire like crazy when you took your foot off the pedal. Fuel mileage went in the toilet, it was pouring fuel through the engine. I suspected water in the fuel since the generator, which feeds from the main gas tank, wouldn't start. A mechanic worked on the vacuum system which was leaking and we added conditioner to the gas. Barely got home and parked it for the winter. This spring I took it in for an ignition tune which did nothing. Changed the fuel filter at the engine. Added Seafoam to the gas. It died 3 times on the way home, finally rolling into the yard and dying again. Lost power in turns and wouldn't rev back up again. Got it started and reved up and would drive to the next turn. I would suspect the famous Ford fuel pump problem but why is it flooding the engine with fuel? Must be a sensor or computer issue. Any ideas where I can start? Local mechanics are helpless if the computer can't tell them what to do. Ford dealer won't look at me because it is a motorhome.
Could the problem lie with the fuel pressure regulator? IIRC, it is vacuum regulated, so if the diaphragm is FUBAR'D the vacuum source will pull the fuel into the engine. Just a thought. Good luck.
So how does that work? Does the check engine light blink in a pattern? Unfortunately the check engine light is not coming on in the motorhome. And yes, these so called "mechanics" are just installers. They don't actually fix anything, just replace whatever the computer tells them to.
So I replaced the fuel pressure regulator and the IAC valve. The engine starts and idles but is very rough. I bought an OBD I Ford code reader. With the engine off ( KOEO test ) I got a code 67 on the self test and codes 33 and 87 on the continuous ( memory ) readout. However when I tried to do the engine running (KOER) test the code reader did nothing, just sat displaying zeros and didn't even try to run a test. I followed the manual for the sequence of the test and warmed up the engine. Tried holding the test key down for 10 seconds, turning the code reader on and off etc. Called Innova and they said the OBD I systems are variable and unreliable. They couldn't tell me why the reader would do one test and not the other, but say they run into this on occasion with older vehicles. So, no joy on this problem yet. Guess I will look for an old mechanic somewhere who knows the engine.
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