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F550 - grey smoke, multiple misfires.

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This 550 has been a source of concern for some time. I've finally had some time with it to do some research.

 

After the first start of the day, it will run well for a few minutes and then, as if someone threw a switch, start running poorly and only on 3 or 4 cylinders.

 

Posted Image

 

 

The FUEL_PW scale is default at 100mS but I've scaled it down to 1mS. When the truck is running well cold, pulse wodth is about 450 microseconds. As you can see at about the -7ish mark, the pulse width nearly doubles. Now the strange part - It is about this time that the truck starts dropping the first 4 or 5 cylinders in the firing order - eerily similar to the way the pulse width falls rythmically to 0. This will continue for several minutes or until you shut it off and restart. Depending on how much heat/time/whatever "something" experiences, the poor running may or may not return (until the next cold soak).

 

As you can see, LOAD and MF_DES also increase when the symptom occurs. Fuel trims don't change but the screen appears to get "busier", for want of a better description. So far I haven't discovered any other aberrations.

 

I'll offer more as the story unfolds.

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An unexpected development - I had inspected the CKP and CMP sensors... the CKP I replaced as it appeared to be distorted as far as the mounting tab is concerned - there was no rust on the block or sensor. I replaced the sensor because "I had it out and they aren't a lot of money". The customer requested that I replace the CMP at his expense at the same time. He needed the truck back and took it. He called the next morning to tell me the problem didn't recur.

 

As far as I can tell, all I have done is slap the hood of the truck and said "begone, Satan!!".

 

We shall see.

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Got your magic wand back from the repair shop, I see Posted Image

 

How ya been dude?

Hey... I been good - sort of.

 

I have this friend, y'see. He doesn't e-mail me (which I like - I mean I like getting e-mails from him, that is) but now and again he texts me (and texting is foreign to some of us old curmudgeons) making me wish he would e-mail me now and again.

 

Broke m'heart when you mentioned your doggie in that other thread. He was a real cool pup.

 

Still messing around with the Alberta holiday idea?

 

FWIW, and so I don't hijack my own thread - this truck is still running good but throws a P0281, #7 fuel trim is about +18 even with the new fuel system... Manual compression had this cylinder consistently 20 PSI lower than the cylinders near it.

 

Any of you guys ever heard of dusting Bon Ami into the intake?

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Yes I have used cleanser in Gas engines before with success. Works well for washed out rings with no other cylinder problems. Just like a quick dingle ball hone cleanup without all the work. Not sure how you would feed it into Diesel engine.

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Old school heavy equipment mechanics would often mention using this stuff to deglaze cylinder walls. AFAIK, they would simply "dust" it into the intake stream.

 

Still, it would be nice if a guy had a clearer picture of what is going on here but it remains elusive.

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30+ years ago I used it per Chevy tech assistance for L82 Corvette engines that used oil. You got a 1/2 cup and open throttle and dumped 1/4 cup and then held it for a few seconds and then closed throttle, open throttle, etc a few times. Then you repeated it to finish the remainder.

When I got this as a fix on first car I thought it was the craziest thing I'd ever heard and I was damn sure glad it wasn't my car. It did work though. The follow up with that first owner (who didn't know what we did) revealed the oil consumption decreased from qt/500 mi to qt/2000 mi.

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  • 1 month later...

Cut to the chase.... looked inside the secondary filter housing and saw sparkleys... did a debris test on the right fuel rail and saw sparkleys....

 

This truck previously had a P0088 and the TSB performed (I hope I mentioned this at some point) but the tanks were never dropped and I am unsure if all the necessary parts were replaced/serviced properly.

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I am told that, in this instance, we didn't. We get mixed stories from Ford.... In one case, the tech was told that metal in the secondary filter is a sign that the filter is doing it's job (read that as company policy states don't spend money if there's a chance that it can make it past warranty). In this case, the FSE said that not cleaning the tanks can lead to bad things (as in repeat failure).

 

I am also told that the tech that performed the repair has, in the past, avoided replacing fuel rails and FRPs. Posted Image

 

Fuel, and any contaminants, will eventually make its way back to the tank.... I think the tank(s) should be dropped and cleaned but, while I have diagnosed this condition in the past, I have yet to repair it personally.

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