Black smoke

[Idi93]

I have a 92' CC 7.3 NA 4x4 5spd w/4.10s. I have put a new return line setup(had leaks), known good injectors w/30K on them(massive white smoke on startup and what sounded like an injector knock), tested glow plugs(all .4-.5 Ohms), good GPC. All of that is good, except it still has a slight tapping sound when revving up, and it starts blowing black smoke when accelerating with more than a quarter throttle. BTW, truck has 180,000 miles, the IP has been replaced in the past, dont know mileage on it though. Also, previous owner removed the timing sensor on injector #1. I replaced that injector line and sensor with a good spare off my other truck. Sorry for the novel, but i figured i couldnt have too much info for yall.

 

[kc0stp]

To fix the smoke just turn the fuel down, whoever did the IP either put a higher flow rate/turbo calibrated pump on or turned it way up. (somewhere on here is a tech articale for turning the fuel down/up)

 

[gatorman21218]

have you timed the pump? A natural engine will smoke dont get me wrong. Timing makes a big difference in the smoke. check your air filter too make sure thats not clogged up

 

[Idi93]

If I am correct, to tun the fuel down, you turn the fuel screw counter-clockwise(allen wrench towards the firewall). If so, I have already turned it down two flats.

 

[Idi93]

have you timed the pump? A natural engine will smoke dont get me wrong. Timing makes a big difference in the smoke. check your air filter too make sure thats not clogged up

I dont have the equipment to time it. I'll have to check at work to see if we have a timing meter for it. The air filter has less than 2000 miles on it(borrowed it from my other truck because I thought the same thing).

 

[icanfixall]

How is the air getting to the filter housing. Sometimes animals make homes in the ductwork and cuts off the air flow. You are correct about the direction to turn the fuel screw to make less fuel but... Are you opening up the injection pump side cover on the passenger side of the pump to turn down the fuel.. If not then you have turned the wrong screw. Hope this helps.

 

[hesutton]

The knocking/ticking noise is concerning for a bad injector or two. That can cause the smoke issues as well. You said 30K on those injectors, but did they set for a while on the shelf or were unused for a period of time? Were they pop tested for opening pressures, pattern, or leaking?

Heath

 

[Idi93]

How is the air getting to the filter housing. Sometimes animals make homes in the ductwork and cuts off the air flow. You are correct about the direction to turn the fuel screw to make less fuel but... Are you opening up the injection pump side cover on the passenger side of the pump to turn down the fuel.. If not then you have turned the wrong screw. Hope this helps.

The air filter housing is just that, and its clean. The one that came on the truck was bent up, so I grabbed the one off my f250 and stuck on it. Yes, I took the side cover plate off. 2=1/4" head bolts, then a 5/32" allen wrench for the screw.

 

[Idi93]

The knocking/ticking noise is concerning for a bad injector or two. That can
cause the smoke issues as well. You said 30K on those injectors, but did they set for a while on the shelf or were unused for a period of time? Were they pop tested for opening pressures, pattern, or leaking?

Heath

The injectors weren't tested. I dont know how long they sat for, but if it helps, I've put the 30K on them during the 2 years I've owned the f250. Unless you mean sat since they were last used? If so, I've put about 5 miles and roughly 75 gallons of fuel through them in the past six months or so. I even fired the f250 up and let it run about 30-45 minutes before letting it cool off and pulling the injectors. I'm kinda at a loss here. I'm thinking about turning the fuel down a few more flats and road testing for a difference. No luck on the timing meter yet. I have my sister dealerships checking to see if they have theirs.
Again, sorry for the paragraphs

 

[f-two-fiddy]

I'd almost bet some the injectors are not sealed to the head. Start the engine, and spray some non flammable penetrating oil around the inj bore. If you see bubbles, the inj is not sealed to the head.

Also, when you removed the inj's, did you replace the return line o-rings? if not, more than likely they are leaking too.

 

[icanfixall]

Anytime injecters are removed the copper washers on the bottom of them called the seal neededs to be replaced. When they get reused they tend to leak.. then carbon builds up in the bores and the injecters may not come out later. Also they have a torque requirement of 35 lbs. How did you run that much fuel thru the engine and only drive it 5 miles in 2 years.. Idle it maybe...

 

[Idi93]

I'd almost bet some the injectors are not sealed to the head. Start the
engine, and spray some non flammable penetrating oil around the inj bore. If you see bubbles, the inj is not sealed to the head.

Also, when you removed the inj's, did you replace the return line o-rings? if not, more than likely they are leaking too.

The injectors were torqued to 37 ft lbs per the workshop manual. The injectors not only got new orings, but connectors, hose, and clamps. But just to cover all the bases, I'll check for bubbles around the injector bores.

Anytime injecters are removed the copper washers on the bottom of them called the seal neededs to be replaced. When they get reused they tend to leak.. then carbon builds up in the bores and the injecters may not come out later. Also they have a torque requirement of 35 lbs. How did you run that much fuel thru the engine and only drive it 5 miles in 2 years.. Idle it maybe...

Installed brand new copper injector seals from work. I slightly overtorqued to 37. I put about 100 gallons of fuel when I moved from lafayette to dallas. That was this past august. Since the move, I have gone around the block some, and let it idle for and hour or so every few weeks.

 

[f-two-fiddy]

What kinda clamps did you use?

 

[icanfixall]

Thanks for answering these questions. It still might need to be turned down more..

 

[icanfixall]

When you opened up the side cover and turned down the fuel with the 5/32 allen wrench which way did you push the wrench... Pushing it towards the firewall turns down the fuel and todards the radiater increases the fuel. As many times as I have made this adjustment one time I went the wrong way in increased the fuel. My test drive showed more black smoke and it took me several days thinking about how this happened. Then the bright light came on when I saw myself doing the wrench turning and going the wrong way... Wow... What a pantload I am for that...