Hi, I recently purchased a 1993 F250 and it was idling rough when I bought it, and smokes heavily when you accelerate. I have checked the fuel lines, made sure they are clear, did away with a Thermoking electric fuel pump someone had installed, after it left me stranded because it quit pumping fuel when it got hot (yet the clear plastic sediment bowl on the pump was full!) I ran the lines to a new stock mechanical lift pump, put an clear inline fuel filter in it, between the output side of the pump and the filter housing, put a new spin on fuel filter on it, fired it up, it ran smooth for about two minutes....I WAS HAPPY !!......for two minutes.......then t went back to the random misfires while idling, and when it does misfire, it throws a puff ob black smoke out the tail pipe, so, I drove it to see if anything had changed there...NOPE !! Same as before, under light acceleration, you can hear the injectors rattling, anything past that, and the injectors quiet down, and black smoke starts rolling out of the exhaust, push it even further, and there is NO injector noise, and real heavy black smoke! It will idle smoothly in between the random misfires, and the longest it will usually idle smoothly between the misfires, is about 10 seconds max. Also I noticed the temperature runs past the middle towards the hot side of the gauge, )just thinking about
timing?) This is driving me crazy, the injection pump doesn't look that old, I put new glow plugs in it also, because EVERY single one was not functioning when I bench tested them, they were Bosch plugs made in Japan? Well..........that's it, any help will be greatly appreciated. Thanks in advance !!

 

timing too advanced maybe? especially with the clatter you describe, that would be my best guess

 

WAG - maybe the cold advance is remaining engaged, not kicking off when it warms up.

 

I cracked all the injectors while it was idling today (one at a time) and it dropped the cylinder each time an injector was cracked, Then I pushed the schraeder valve in while it was running to see if there was a lack of fuel when it would misfire, nope, steady stream the whole time, I put the fuel pressure gauge on the valve (again) and I got 6-7 lbs at the filter housing, I unplugged the cold start solenoid, no difference, I looked at the pump alignment marks, they are almost exactly in line, but the pump is favoring the passenger (advance) side, but the marks are still touching by more than half, you have to look twice to see that it is not perfectly in line. This thing is driving me crazy, the sad thing is, it's a beautiful truck! And it's a 5 speed like I wanted, I always seem to get the ones that are doing something never heard of before! Lol P.S. When I first start the truck for the first time of the day, it idles perfectly for almost a minute, then it goes into it's random misfiring, it will idle smooth for 5 to 10 second intervals between it's misfiring , and it still smokes like hell (black) if I take it down the road when I accelerate.

 

Mess with the timing. You've got nothing to lose.
If that doesn't fix it, you can replace the IP and injectors and it will /certainly/ fix it, but that's kinda the nuclear option.

 

those timing marks mean nothing. you need a meter of sorts to accurately time according to the fsm. mine was also on the marks but retarded somewhat. ran like crap cold, misfire, blue smoke, no power etc.

 

True, but this truck was running perfect, then he parked it at a friend's house, let his friend show it to someone, his friend said it wouldn't start, actually killed the battery, and fried the starter trying to start it, it sat for two months, then someone told him it had water in the tanks, and supposedly, they drained the tanks, then put a Thermoking electric fuel pump on it, it ran good for a while, but one day he started it, and it started running like this, so I don't think the timing would have moved. I do know it is driving me crazy! Lol! The Thermoking pump would not pump when it got hot, so I did away with it, I put a new mechanical pump back on it, and a clear inline filter.

 

Injection pump is sticky and probably cruddy inside. Which is probably throwing the timing off too.
You can try the ATF trick -- fill the water/fuel seperator with ATF, run the engine for 30 seconds to get the ATF into the pump. Let it sit overnight. Start it and run it hard. It might just solve the problem.

Otherwise... You need a new IP.

 

I assume you are talking about the fuel filter since it has the water drain on the bottom, correct?

x2 on this idea. Use ATF or others have used Diesel Kleen. Not sure which works the best. I have done both depending on what I have on hand when I change my fuel filter.

If you haven't already, I would get rid of any old fuel in the tanks and refill them with fresh diesel and the additive of your choice....probably a double or triple dose for the first couple of tanks.

And the timing marks don't mean a whole lot as far as setting the timing. They are mostly just to get it close enough to start and allow you to set the timing correctly.

 

that was a major upgrade.approx how long did the truck run for,until the fuel pump quit working?
it almost sounds like instead of running the relay trigger line from the FSS,they mistakenly ran it from the timing advance solenoid.that would make the truck run fine when cold,but after a few mins of running when the solenoid was shut off,so would your electric fuel pump.
those are super long lasting fuel pumps.it's what they use of the reefer trucks.

insure the FSS wire is plugged into it's correct location on the ip.look to see if it has full,clean power and see if that's where they tapped into to trigger the relay.if something like a bad FSS wire is the trouble,then this would explain why the truck wants to keep missing and the fuel pump wont stay running.insure they used the main power draw directly off the battery.look to see what pin they used from the FSS line was on the relay.if you see no relay then there's your problem.they ran the pump directly off the FSS and it overloaded this circuit.
the ip and injectors are good for approx 100k miles (in peak performance) and you should be running motorcraft glow plugs.

how many miles are on the truck and is it the original engine?

 

hi, the thermal King electric pump kept running, it just did not anything when it got hot. So that is why I put a new mechanical pump back in it, I have plenty of fuel to the pump, yesterday I took the feed line off that goes into the filter housing, blew into it several times to empty some of the fuel out of the filter. I did not have any trans fluid here, my first choice, but I did Spray about a quarter of a can of sea foam deep creep penetrating oil into the filter housing, then I cranked it, but it on for about 30 seconds, then let it sit for about an hour or so, cranked it up, it ran smooth for about 40 seconds, then went back to its usual crap! today, I plan to get some synthetic transmission fluid and do the same thing, but let it sit overnight this time.

 

OK, went and got a quart of V Max synthetic transmission fluid, took the fuel filter off, emptied the diesel out of it, then filled it with transmission fluid, put it back on, and fired up the truck, it was running perfectly, as it always does the first 40 seconds or so, I let it run about 30 seconds, then shut it down, I will fire it up tomorrow afternoon and see what happens. I thought about it later, but, I wish I had added some Marvel Mystery Oil with it! Well, I guess we'll find out tomorrow what happens! Wish me luck.........I NEED IT ! Lol