Join Date: Nov 2009
Location: Norwalk, CT
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Injector Harness/failed FICM w/good voltage- what was your symptoms??
Ive exhausted all my possible thoughts about this scenario.
Truck runs well 99% of the time. When it doesnt, it has the SLIGHTEST misfire. Its very hard to hear/feel it. Ive had three different friends (all of which are gearheads) listen to the truck, from inside the cab while driving, and from outside the cab. None of them hear the miss. Either I am going crazy, or its so slight when it happens, no one but myself can hear it (because I drive it everyday?).
Cold starts are good, but not great. FICM stays above 47.5V, but if its below 20*, and the truck isnt plugged in, it romps for 2-3 seconds.
I mostly get the miss when the truck is warm, 20-30 min of continuous driving. It almost feels like a slight shudder.
It has tons of power, even when I feel the slight miss, if I roll into the throttle, it is either so slight I can no longer feel it, or it goes away.
Only other symptom, when the truck is warm, on the highway, in top gear, on part throttle acceleration, it will surge/buck/miss. Fuel pressure is steady at 62-65psi.
I just ordered a harness, fingers crossed this fixes it ( I HATE throwing parts at something to fix it, much rather troubleshoot and FIND the problem).
I have a strong feeling if a new harness doesnt fix the issue.
My only other thought is the FICM has some other issues going on. I doubt that the only time an FICM fails is when the power supply starts to crap out. Maybe when it gets warm, something is breaking a connection?
FICM never drops below 47.5V (FICM was replaced about 2 yrs ago).
8 new injectors 3 weeks ago.
New frame mounted fuel pump with new injectors.
New engine side fuel filter.
Fresh T5 oil.
New turbo this past spring, when Ford replaced the headgaskets (failed BO).
No EGR systems.
Never pukes coolant.
Never loses coolant.
I run RevX every other oil change, and Power Service Cetane boost every fill up.
I push it into high boost almost everyday, for at least a 2-300yd sprint.
One of the reasons I recently thought why I have a damaged harness; this engine has been torn down to the bare block for head gaskets twice, once in cab, once cab off. And when I did the injectors 3 weeks ago, I obviously had my hands all over the harness. I am thinking the harness could have a chafed/broken wire. I see a lot of wiring harness issues at work with Yamaha outboards. Mostly due to improper routing/securing by previous techs/DIY'ers. Thats why I dont want to rule this out on my behalf.
Somebody, anybody, ideas? Input?
I love this truck, but its drives me nuts sometimes. See sig for my mods.
Irate SS T4
ODP St3 Manifold
Rudy's Intake elbow
PSP Coolant Tank
Mishimoto Rad. & IC pipes
Jugger Pump w/DIY RR
Fuel PSI Gauge
USCG 50GT MMC
Yamaha Outboard Master Tech