06-26-2020, 07:43 AM
big problem, please help if you can. Last night I backed up on gravel road for 300 feet, at high speed, pulled in and parked. This morning this happened:
Good start, all sounded well and normal as it has been for a year: in less than 2 minutes, extremely rough, only run (barely) at certain throttle openings, eventually dies completely, heavy fuel usage. No restart. Let sit for 20 minutes, good start, in 45 seconds goes to extremely rough, then no run. Will run at high RPM, with some occasional misfire.
Here is what has been done:
removed cat from exhaust system. Same.
Fuel volume from rail= very good. Fuel pressure in rail just under 40 psi. Return fuel line OK. Tank pressure relieved.
Rail leak-down test=OK, holds 35 lbs for 10 minutes, (very slight drip at my fittings).
Air cleaner removed.
here's the killer: Vacuum test about 10-12 inches hg. Plugs very sooty. It's lke fuel is justbeing dumped, but injectors don't leak, even if one did, all plugs are sooty. 4 injectors did not fail at one moment.
I saw the FSM on exhaust blockage, removed exhaust manifold completely . Problem/symptoms remain.
Could this be valve timing as in slipped belt?
MAF is fine. EGR is OK. It started when I backed up, WOT...coincidence?
I am stumped. It runs really well just like always....then 1-2 minutes just deteriorates to will not run. What can it be?
Good start, all sounded well and normal as it has been for a year: in less than 2 minutes, extremely rough, only run (barely) at certain throttle openings, eventually dies completely, heavy fuel usage. No restart. Let sit for 20 minutes, good start, in 45 seconds goes to extremely rough, then no run. Will run at high RPM, with some occasional misfire.
Here is what has been done:
removed cat from exhaust system. Same.
Fuel volume from rail= very good. Fuel pressure in rail just under 40 psi. Return fuel line OK. Tank pressure relieved.
Rail leak-down test=OK, holds 35 lbs for 10 minutes, (very slight drip at my fittings).
Air cleaner removed.
here's the killer: Vacuum test about 10-12 inches hg. Plugs very sooty. It's lke fuel is justbeing dumped, but injectors don't leak, even if one did, all plugs are sooty. 4 injectors did not fail at one moment.
I saw the FSM on exhaust blockage, removed exhaust manifold completely . Problem/symptoms remain.
Could this be valve timing as in slipped belt?
MAF is fine. EGR is OK. It started when I backed up, WOT...coincidence?
I am stumped. It runs really well just like always....then 1-2 minutes just deteriorates to will not run. What can it be?