6.0 Running Rough

01PSD

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My brother's 2007 6.0 has been running a little rough for the past week or so, and seems like it's progressively gotten worse. At idle and for the first few miles going down the road it would have a bad miss, but would clear up once the oil got nice and warm. Now.. it doesn't clear up. Injectors? FICM tested good when we tested it yesterday morning, 48.2 or 48.3 volts before and after cranking.

And yes I suck at holding cameras.. my hands are very shakey LOL

http://www.youtube.com/watch?v=wSkV...DvjVQa1PpcFPRpUMdffHMIw2MjM_RlcJwleo8WMTuhtk=
 

golfer

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if it runs rough...annnd the FICM tested good..then it's injector time.

FWIW since we do about 40 FICMs a day, LOL....I'm pretty familiar with these types of issues...

if the vehicle has less than 80k miles on it...then you could get away with replacing the one(s) that show up as having the least affect on cylinder balance...and maybe some Rev-X (yes, I just said that, LOL)

if it has more than 110-120k miles...go ahead and do all 8.

The spool valves in the 6.0L injectors are a pretty crappy design, and have no allowance for wear...so when the spool get's loose in its' bore...it can get cocked in there and hang...especially with cold thick oil.

good luck :D
 

01PSD

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It was just at the dealer last year for injectors 4 and 8. They wouldn't replace them all :/ so now here we are LOL
 

golfer

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^^ no chit...

we just added another mechanic who worked at Ford for 8 years...and he was surprised when 'got' to do all 8 injs in a 6L on his first day here, LOL

not to get too off topic...but think of the spool valve as a piston in a cylinder bore...without piston rings.

the solenoids (when energized by the FICM) pull the spool L or R (open or closed) to allow the HPOil to enter the injector...

when the 'piston' (spool) get's loose(r than it should be)...it can get a little cocked sideways and will drag on its' bore...and since there isn't anything mechanical pulling it (simply a magnetic force)...the drag of the (loose) spool won't allow it to move consistently. So when the spool (occasionally) sticks...that injector doesn't fire..at least not that time.

Back when we were remanufacturing the 6.0L injectors...we often had some pretty PO'd customers...describing the intermittent misfires just like this.

It took us quite a while to figure out WHY we weren't catching these issues on our injector flowbench...but we finally caught on.

While flow testing the injectors (minimum 4000 shots at various pressures and pulse width to simulate idle, part throttle, WOT, etc) we wouldn't EVER let a set of injector leave until they were within 1-2% of each other...

the PROBLEM wasn't that we were dealing with an injector that was 1% high or low when compared to the others...

We were dealing with injectors that would be 100% low 1 or 2 PERCENT OF THE TIME!!!!!

bigggg difference.

you'd NEVER feel a 1-2% difference in injector balance in a truck, IF the questionable injector WAS only 1 or 2% off all the time...but...if the injector is NOT firing at ALL 1 or 2% of the time...then that's what you feel in the truck as an intermittent misfire...

we quit remanning the 6.0L injector about 4 years ago...and since selling & modifying the OEM Ford injectors..have had very very few problems...and lots of very happy customers!

Daily, I get calls from customers who purchased reman injectors from XYZ company...who have the exact same symptoms as their stock injectors had...which is no surprise since the spool valve can't be successfully remanned.

It would be like trying to rebuild an engine without having 10 or 20 over pistons...no matter how good the machine work it...if you can't regain that lost clearance between the spool and the bore...the injector is still going to have the exact same problem...

The injectors available at the Ford (or International) dealer are the only injectors that come with new spool valves...Alliant Power 6.0L remans are just as crappy as the others in our experience...

any injector shop can disassemble the injectors...clean them, replace nozzles, cut pistons, etc, etc...but the spool valve is going to have the same wear & issues when it is shipped out as when it was received by XYZ company...
 

01PSD

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Turned out to be injector #1, and that's all Ford replaced :/ We'll see how far it goes before other injector problems appear! LOL
 

dieseljosh07

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Better check fuel pressure before installing new injectors. Low pressure kill injectors. The updated fuel pressure regulator spring is a good upgrade to do if you don't already have it.
 

Mdub707

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^^ no chit...

we just added another mechanic who worked at Ford for 8 years...and he was surprised when 'got' to do all 8 injs in a 6L on his first day here, LOL

not to get too off topic...but think of the spool valve as a piston in a cylinder bore...without piston rings.

the solenoids (when energized by the FICM) pull the spool L or R (open or closed) to allow the HPOil to enter the injector...

when the 'piston' (spool) get's loose(r than it should be)...it can get a little cocked sideways and will drag on its' bore...and since there isn't anything mechanical pulling it (simply a magnetic force)...the drag of the (loose) spool won't allow it to move consistently. So when the spool (occasionally) sticks...that injector doesn't fire..at least not that time.

Back when we were remanufacturing the 6.0L injectors...we often had some pretty PO'd customers...describing the intermittent misfires just like this.

It took us quite a while to figure out WHY we weren't catching these issues on our injector flowbench...but we finally caught on.

While flow testing the injectors (minimum 4000 shots at various pressures and pulse width to simulate idle, part throttle, WOT, etc) we wouldn't EVER let a set of injector leave until they were within 1-2% of each other...

the PROBLEM wasn't that we were dealing with an injector that was 1% high or low when compared to the others...

We were dealing with injectors that would be 100% low 1 or 2 PERCENT OF THE TIME!!!!!

bigggg difference.

you'd NEVER feel a 1-2% difference in injector balance in a truck, IF the questionable injector WAS only 1 or 2% off all the time...but...if the injector is NOT firing at ALL 1 or 2% of the time...then that's what you feel in the truck as an intermittent misfire...

we quit remanning the 6.0L injector about 4 years ago...and since selling & modifying the OEM Ford injectors..have had very very few problems...and lots of very happy customers!

Daily, I get calls from customers who purchased reman injectors from XYZ company...who have the exact same symptoms as their stock injectors had...which is no surprise since the spool valve can't be successfully remanned.

It would be like trying to rebuild an engine without having 10 or 20 over pistons...no matter how good the machine work it...if you can't regain that lost clearance between the spool and the bore...the injector is still going to have the exact same problem...

The injectors available at the Ford (or International) dealer are the only injectors that come with new spool valves...Alliant Power 6.0L remans are just as crappy as the others in our experience...

any injector shop can disassemble the injectors...clean them, replace nozzles, cut pistons, etc, etc...but the spool valve is going to have the same wear & issues when it is shipped out as when it was received by XYZ company...

Rosewood claims to have new spool valves in their 6.0 rebuilds.
 

01PSD

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As far as checking fuel pressure goes, would it hurt to use an analog fuel pressure gauge (already have 3 other autometer gauges in a pillar pod, could just get a quad pod) or is digital preferred (Edge monitor, etc.)? Blue spring upgrade is probably in the near future as well.
 

dieseljosh07

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A analog gauge would be a great addition. Once you have one you will start waiting longer after the glow plug light is off to start the truck. Most truck Only build to around 30psi by the time the light goes out.
 

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