Misfire
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Misfire
I have a 99 f350 v10 with 175k. Last week we went to drive it and after 1 crank my motor sounded like it wanted to lock up. After the second attempt it started up and idled real rough for a minute everything cleared up and I went to drive, white smoke so bad I couldn't see behind me, after about a half mile it cleared up and everything was fine. Coming back home, same symptoms all over again, exhaust smelled like raw fuel, so leaking injector?
I replaced all 10 injectors with a set of remanufactured Bosch I found on Amazon for $130 compared to the motorcraft from rockauto for $400. Replaced the fuel pressure regulator too (autozone). Everything worked great until I took it down the highway. It's back to running rough and smoking. I checked everything, nothing came unplugged. Did a coolant system pressure check, held at 16psi. Cylinder compression test, all cylinders are 150-165 except cylinder 7 is at 130.
I'm thinking it's the crap injectors but I'm not sure
I replaced all 10 injectors with a set of remanufactured Bosch I found on Amazon for $130 compared to the motorcraft from rockauto for $400. Replaced the fuel pressure regulator too (autozone). Everything worked great until I took it down the highway. It's back to running rough and smoking. I checked everything, nothing came unplugged. Did a coolant system pressure check, held at 16psi. Cylinder compression test, all cylinders are 150-165 except cylinder 7 is at 130.
I'm thinking it's the crap injectors but I'm not sure
Fleet Mechanic
Joined: Jan 2016
Posts: 1,804
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I have a 99 f350 v10 with 175k. Last week we went to drive it and after 1 crank my motor sounded like it wanted to lock up. After the second attempt it started up and idled real rough for a minute everything cleared up and I went to drive, white smoke so bad I couldn't see behind me, after about a half mile it cleared up and everything was fine. Coming back home, same symptoms all over again, exhaust smelled like raw fuel, so leaking injector?
I replaced all 10 injectors with a set of remanufactured Bosch I found on Amazon for $130 compared to the motorcraft from rockauto for $400. Replaced the fuel pressure regulator too (autozone). Everything worked great until I took it down the highway. It's back to running rough and smoking. I checked everything, nothing came unplugged. Did a coolant system pressure check, held at 16psi. Cylinder compression test, all cylinders are 150-165 except cylinder 7 is at 130.
I'm thinking it's the crap injectors but I'm not sure
I replaced all 10 injectors with a set of remanufactured Bosch I found on Amazon for $130 compared to the motorcraft from rockauto for $400. Replaced the fuel pressure regulator too (autozone). Everything worked great until I took it down the highway. It's back to running rough and smoking. I checked everything, nothing came unplugged. Did a coolant system pressure check, held at 16psi. Cylinder compression test, all cylinders are 150-165 except cylinder 7 is at 130.
I'm thinking it's the crap injectors but I'm not sure
Postmaster
Joined: Jul 2015
Posts: 4,392
Likes: 22
From: very South Texas
wait.. did you replace the spark plugs at the time of the injectors... its a Must..
raw fuel on used/old plugs are real hard on coils... and plugs not firing anymore...
compression test is next... or leak down test...
do not guess... or use information from before...
start over on the tests... or you could get Lost in the MIX...
raw fuel on used/old plugs are real hard on coils... and plugs not firing anymore...
compression test is next... or leak down test...
do not guess... or use information from before...
start over on the tests... or you could get Lost in the MIX...
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Fleet Mechanic
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Start it cold and then shut it off before it gets warm. Start pulling plugs until you find the wet one. Again, I would think it is the weak cylinder. Find someone with a coolant pressure tester and put it on your system. Pump it up and watch for pressure loss.
Edit to add: If it is still misfiring then a cylinder contribution test should pinpoint the dead cylinder.
Again, my best guess is still a blown head gasket or a cracked head. If you are still getting white steam out the tailpipe you do have a coolant leak into the engine.
Edit to add: If it is still misfiring then a cylinder contribution test should pinpoint the dead cylinder.
Again, my best guess is still a blown head gasket or a cracked head. If you are still getting white steam out the tailpipe you do have a coolant leak into the engine.
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I did a coolant pressure test and it held at 16 psi for an hr.
Im throwing in the towel. It's going in to the dealer tomorrow. Lucky my gf works in the service department so it wont cost me my left nut (hopefully)
Im throwing in the towel. It's going in to the dealer tomorrow. Lucky my gf works in the service department so it wont cost me my left nut (hopefully)
Fleet Mechanic
Joined: Jan 2016
Posts: 1,804
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