My neighbor came limping home in his barely running '87 F250 5.0 liter V8 and asked me to check it out. I dsicovered only cylinders 1, 5 and 6 were firing, did the usual ignition and FI timing checks, then did what I should have done to start with. I squirted some quick start fluid directly into the throttle body and all 8 cylinders fired up for a few seconds. When I pulled the injectors, the filters on 1,2,4,6,7 and 8 were all clogged with fuel residue particlate all the way to the top. I cleaned an test all of them and put them back in and now the truck runs fine. But the question of how this happend remains. According to the owner, the dramatic power loss had happened all at once, not as if cylinders had been dropping out one-by-one over time. It makes sense that starting from a a baseline of eight clean filters, they would have collected particulate at the same rate then topped out and quit at the same time. (The filters are thimble-shaped, so they will pass fuel right up to the moment they top out.) By then why were three of them only about half clogged and still passing fuel, keeping the engine running? Possibly those three could have been cleaned or replaced at some time without the other three being touched. That's the best theory I can come up with. Does anybody have another one?

 

The fuel pump passed a chunk of debris and those five just happened to catch the stuff. Nothing complicated about it and really nothing to try and disect, S#*T happens.

 

Anything that comes out of the high pressure pump has to get through the big fat inline flilter before it gets to the rails. That leaves the residue that builds up in the fuel line between the big fat filter and the rails. I suppose that could build up over time to the point that a lot gets released all at once, especially in a truck that sits most of the time, like this one. I'm mostly just trying to figure out the likelihood of its happening again any time soon. Big job pulling those from a V8 with extra heavy duty suspension, so the hood comes up to my chest. I have to stand on a chair, and even then it's a stretch to reach things.

 

I wonder if the big fat inline filter came apart inside and let some trash pass through.... It might be worth the trouble to change it if you haven't already...

 

I think White 97 has it right. A few months ago my Escort was acting up, and when I took the fuel filter out I heard it clanking inside. Upon taking it apart I found the filter end cover had come off. This was only about a year old filter so I suppose it didn't have too much crud in it.

I have had another filter come apart internally a few years ago, but I forget what vehicle other than it was carburated.

Remember a lot of these parts are now made in China and quality control is terrible.

So take apart that old filter and tell us what you see.

 

I replaced the filter about a year ago as part of a different fix, did notice that the old one had something rattling in it. I don't remember if the new one rattled, and I don't know if it rattles now, I'll have a look. Thanks for the tip.

 

It wouldn't have been the old one from a year ago that caused the sudden problem, but the current filter. If it did pop apart internally, then all the dirt in it would be dumped at once into the fuel rail.

On my Escort, the injectors didn't get clogged, but the filter sock in the gas tank did. I suppose the fuel flow was high enough that almost all of it went past the injectors and then through the pressure regulator, thence back into the fuel tank.

My filter was also about a year old when it failed. Interestingly, the filter inside was very soundly glued to the canister, but the metal cap on its end had fallen off. Perhaps it was oily or dusty when glued on at the factory.

 

And if you're buying cheap gas, it would be a plus to start buying better quality branded fuel. Or at least make sure the station you're buying from has filters in their gas pumps to avoid getting trash into your tank.

 

I believe this type of fuel filter failure is due to a manufacturing defect, not bad gasoline.

 

I was saying that if the old filter rattled, it was reason to suspect the new one might be rattling and to inspect it. So I opened the old filter and found that it wasn't attached to the casing at all, it relied on the tight fit to keep it centered. I checked the current filter as best I could without actually removing and draining it, no rattle. It may be that the rattle in the old one was an artifact of its having been removed and drying out, like a gourd--it was made in Mexico

Next step is to remove the current one and look anything suspicious. Or, I can just file this as a cold case, to reopened if and when the truck fails again.

Thanks to everyone for their support.