Multiple Fuel Problems/Shifting Problems?

[JohnLeePettimore]

Alright y'all I got this 93 7.3 IDI NA about a month ago and i have multiple problems and need some guidance on what order I should try to knock my problems out.

No Power/ Billowing Black Smoke​

- A little background info: the PO straight piped it with a 12" cat stack (was a teenager and was dressed like Fred Durst, of course he wanted it to roll coal.). It poured black smoke past 1/4 half throttle. Based on the stack I suspected the IP was turned up... a lot. I turned the pump down 4 whole flats, and now instead of pouring smoke at 1/4 throttle, it doesn't smoke until 1/2 throttle. Do I keep turning the fuel down?

Hard Start/ Losing Prime​

- The truck loses prime after a couple hours. It has an electric lift pump, so I can turn the key and purge the Schrader valve. It spits air out for a couple seconds until it turns into a steady stream of fuel. When it's above 30 it fires right up (usually less than 2 seconds of cranking.) I figured I would do some preventative maintenance and hope maybe it would help a little. I did the fuel return line kit with Viton O-rings. The fuel lines all had a date code of 2011, so I replaced all of the rubber line between the filter head and the fuel selector valve. I also found the line to the lift pump was laying on the exhaust manifold... ***... how it had not completely blown through yet and caught the whole truck on fire was entirely beyond me. Anyways... I couldn't replace the line between the selector valve and the tank because I don't have the will power to drop fuel tanks anymore lol. THE FRONT TANK HAS A LEAK. It seems to be leaking where the strap meets the bottom of the tank. Could this cause any problems? I figure it wouldn't because it has a lift pump after the in-pump tank, but I'm not here because I know everything. I'm sending it to a shop to have the tank replaced with the rest of the lines. The rear tank had a broken fuel cap so I've only been using the front, suspecting water got into the rear, until I can drain it all out.

Transmission Shifting Issue​

-Like I said it billows smoke after half throttle, it takes over a minute to get to 35mph, but after 35 it seems to clear up and accelerates decently.
-I'm also having shifting issues. It shifts into 2nd a little late, and very hard. However, to get it to shift into third, I have to completely let off the throttle for a couple seconds. This issue alone makes the truck almost undrivable. Drivers behind me hate me, and reasonably for taking over a minute to get the speed limit. I checked the FIPL (TPS) it reads about 1.2v at low idle and about 3.5v at WOT. There is no break in voltage when smoothly applying throttle. From what I understand, it should be over 4 volts at WOT, but when maxing out the adjust it's just barely under 4 volts, and idle goes up to almost 2 volts. Does this narrow range suggest a bad FIPL/TPS? And if so, could this cause my hard/late/not shifting problem? The OD light flashed on me once a couple days after I got it, but none since, even though the problem has remained consistent. Also questioning if my runnability issues could cause poor shifting.

I thank you very kindly for any responses, y'all keep this generation of trucks going and without you, mine and many others would be in a junkyard never to find a home again.

 

[IDIBRONCO]

FYI these trucks do not have a pump in the tanks.
I think that you need to do something about getting at least one good fuel tank before too much longer, Your front tank probably has a rust hole in it since mud, road salt, and other corrosive things like to get caught between the straps and tank. Will it cause an issue? Probably not unless you let enough fuel leak out that the fuel level is at or below the fuel pickup in the tank.
You do need to remember that these weren't power houses from the factory so, if this is your first IDI, it may feel like it's down on power. I'd suggest turning the fuel down a little more to see what that does. I would also guess that the kid probably maxed out the fuel screw since it would roll coal at 1/4 throttle. This would also be a good time to have your timing checked.
Finding the cause of your fuel drain back can be a bear sometimes. It's a lot of trial and error. Fixing the lack of maintenance from previous owners can make the Pope cuss sometimes, but these are pretty reliable trucks after all of those bugs get worked out.

 

[JohnLeePettimore]

FYI these trucks do not have a pump in the tanks.
I think that you need to do something about getting at least one good fuel tank before too much longer, Your front tank probably has a rust hole in it since mud, road salt, and other corrosive things like to get caught between the straps and tank. Will it cause an issue? Probably not unless you let enough fuel leak out that the fuel level is at or below the fuel pickup in the tank.
You do need to remember that these weren't power houses from the factory so, if this is your first IDI, it may feel like it's down on power. I'd suggest turning the fuel down a little more to see what that does. I would also guess that the kid probably maxed out the fuel screw since it would roll coal at 1/4 throttle. This would also be a good time to have your timing checked.
Finding the cause of your fuel drain back can be a bear sometimes. It's a lot of trial and error. Fixing the lack of maintenance from previous owners can make the Pope cuss sometimes, but these are pretty reliable trucks after all of those bugs get worked out.

Thank you for the response, i appreciate it a lot. I adjusted the FIPL and got much better shifting, still not perfect but drivable. I also ended up turning the fuel down 9 flats (was adjusting 3 at a time) still running a little rich but it doesn't leave a smoke screen behind me or choke out anymore. I also didn't know the tanks don't have pumps on these. I just made the assumption that it was like my 96 gasser that does have them in the tank. Good to know though, thank you. I've done the return line kit but I'm not confident that NAPA has the best quality part, lesson learned. I decided in just gonna jerry rig a smoke machine together and check for return leaks again and also air intrusion before the lift pump. Id rather do some diagnostics before i start buying parts. I'll pull the fuel filter tomorrow to see if I'm losing fuel before or after the filter head. I'll come back with more information when i can find it. Thank you again, it's much appreciated.

 

[Old Goat]

NAPA sells the same Chinesium parts every one else sells, just at a higher price.

The Fuel Pump on these engine`s is refered to as a "Lift Pump", is down low on the Passenger side.
There is a Rubber Curley "Q" hose connected to it. that could be old and cracked, especially where the Clamp`s were over tightened. 3/8" hose.
Mine was like that, and later had the pump it`s self starting to weep fuel, bottom of pump was wet.

Anytime the Pump is replaced, do the hose at the same time you already have it apart.

You will need to purge you mind of Gasser thinking....


Goat

 

[JohnLeePettimore]

NAPA sells the same Chinesium parts every one else sells, just at a higher price.

The Fuel Pump on these engine`s is refered to as a "Lift Pump", is down low on the Passenger side.
There is a Rubber Curley "Q" hose connected to it. that could be old and cracked, especially where the Clamp`s were over tightened. 3/8" hose.
Mine was like that, and later had the pump it`s self starting to weep fuel, bottom of pump was wet.

Anytime the Pump is replaced, do the hose at the same time you already have it apart.

You will need to purge you mind of Gasser thinking....


Goat

Fortunately this truck has an electric lift pump with the mechanical pump blocked off and lines disconnected. I replaced all of the lines between the fuel filter head and the selector valve, as i can't get to the rest without removing either the tank or the bed. I think the next thing I'm gonna do is smoke test the entire fuel system, including the return system and the steel injector lines. I wouldn't be surprised if it needed every single thing replaced, but i just want to check before i buy a bunch of parts. I also plan to tap and plug the fuel filter heater and the other thing on the filter head that I'm blaming on the name(had a tsb to plug). Thank you for the response