2004 ford e350 super duty 5.4 v8 175,000 miles
trouble is that every once in a while the engine wont pickup and excellerate.
I pump the gas and it picks up and goes on. It has died in the past but restarts and usually runs fine. Also if i just let it idle it will idle most of the time fine. But can't get out of traffic easily.
Have changed the fuel pump & the fuel relay. Fuel filter was changed back last winter miles were around 167,000 the. Not because these were good but no fuel for the relay then later the pump same thing. Fuel filter was changed back last winter miles were around 167,000 then
It does not do this everytime often it goes days and works fine.
I can't find a vacuum leak on the ac air damper as it cuts off air in cab when accelerating in summer. Wonder if this could be a problem? After crusing speed or letting up on throtel air flow in cab returns. I dont see where this damper is...?.?
trouble is that every once in a while the engine wont pickup and excellerat
Monitor fuel pressure. Check TPS. The AC cutting off is strange re: relation to this. What's your LTFT values?
I may have missed the target. I mean the air damper moves to close off air flow on the venting in the cab. The ac is staying engaged. Its the air flow dampers that cut off air flow in the cab. Sorry
Well I found a way to check fuel pressure
Fuel pressure is in range
Now seems I have the trouble narrowed.
I have no fire to ignition. Its staying broke now. I went on and changed the pcm ouch and crank shift pos sensor. Still no fire. Will put on my obdII today see if I get a code.
LTFT values? I'm way out of my league here.
And recommending monitor fuel pressure? Ok do I drive it til this happens? Last week it only gave me trouble 1 time and that was when I tried to start it. Rest of week started fine, ran fine. I did tend to keep it reved up more than my usual driving. Often going over the speed I usually drive at. I'm usually around 45 to 55 on country roads and 60 to 80 on highways. I'm still not exceeding my stated speeds here just keeping closer to the high end than usual.
The 1 time starting it I switched the key off all the way and retried it and it started right up. The ignition switch was a sore spot with me cause it would not lock and consistently had to relock it the past. When I was trouble shooting the fuel pump relay I decided then to fix that confound key problem. So now that is no longer a problem and works fine. I decided that next time it happens I will try the ign key off all the way and see if it clears the trouble.
LTFT= Long Term Fuel Trim. Can be checked with scan tool. Should be within +- 4. Basically insuring you don't have an air leak (possibly one that changes when driving?... not common but possible as it could explain what's happening). Yea, they could have made checking/monitoring fuel pressure a lot easier... a simple sensor on the fuel rail... they have sensors for fart detection (humor to state point of useless stuff/sensors installed) and don't have one for fuel pressure info to ecm and to be monitored. I think this is the most likely cause of it having the power/lack of response, temp loss of fuel pressure. To monitor, you'll need a fuel pressure gage you can attach to the rail and leave there with fuel hose extension so you can place gage where you can see it while driving. I suspect you'll see a drop when the condition occurs and if so, will KNOW where to concentrate... finding the cause of the pressure drop. Hence the need to monitor else it's just a best theory (easy to miss intermittent electrical connections when they check good). I'd get this resolved before attacking ac damper. Did you check tps?
I think you have a vacuum leak
Well I found a way to check fuel pressure Fuel pressure is in range Now seems I have the trouble narrowed. I have no fire to ignition. Its staying broke now. I went on and changed the pcm ouch and crank shift pos sensor. Still no fire. Will put on my obdII today see if I get a code.
Well I found a way to check fuel pressure Fuel pressure is in range Now seems I have the trouble narrowed. I have no fire to ignition. Its staying broke now. I went on and changed the pcm ouch and crank shift pos sensor. Still no fire. Will put on my obdII today see if I get a code.