[Z Dude]

Ok so forgive me this is my first time asking a question on a forum... I have a 96 f250 7.3 that started running rough, nothing consistent just here and there. Then it progressed to a rough idle and constant sputter (as if it was running low on fuel) so I replaced the cps and then the icp+fuel filter. At first it seemed to run fine but soon after that it completely died and is no longer running, it will turn over on a shot of ether, (yes I know to never use ether I just wanted to isolate it to the fuel). Truck gives no codes, I was told to check the valve cover gasket where the wire harness goes through and it appears to be in perfect shape. Running out of ideas and sorry if I missed anything pls let me know if I did
Also about 100 miles ago I replaced the mechanical lift pump down in the engine bay under the turbo pedestal. Any ideas what the problem might be?

 

[Patrick Feeley]

Welcome! It could be many things. Also, just because it fired on ether doesn't mean it's isolated to a fuel problem (and yes, don't use it). Is it a 5-speed or automatic?

Is the Check Engine Light illuminated?
Are there any mods on the truck like a chip or tuner?
Is the Wait-To-Start light coming on normally?
Are all the underhood fuses good?
Is the oil level good?
Does the tach move when cranking?
Any white smoke out the tailpipe when cranking?
Wat's the fuel pressure when cranking?
What are the fuel tank levels and have you tried switching tanks?

Answers to these will get the folks here going. Cheers!

 

[ArcticDriver]

it will turn over on a shot of ether, (yes I know to never use ether I just wanted to isolate it to the fuel).

Z-Dude,

Not Cool.

😎

 

[1999f-250superduty]

Have you checked fuel pressure?

 

[Craig Alberts]

As the prior post says...check fuel pressure, open your bowl and see if there is fuel if not and if not - check your fuel tank selector valve. Do both tanks register correctly on the fuel gauge?

 

[Z Dude]

As the prior post says...check fuel pressure, open your bowl and see if there is fuel if not and if not - check your fuel tank selector valve. Do both tanks register correctly on the fuel gauge?

Ok yes I borrowed a fuel pressure gauge when the problem first started and it seemed to be running at normal psi, I forget the exact numbers but I verified them via another forum. No the front tank doesn’t register and rear tank was half full, I was very aware because I was on a road trip when this happened and I had fueled up both tanks at the same time. I completely used the front tank and was half way through the rear tank when it finally went. What’s odd is today when cranking over I checked the fuel bowl and it now has almost nothing in it! Not what you mean by fuel tank selector valve I will look it up and check it. Thanks so much

 

[Z Dude]

Welcome! It could be many things. Also, just because it fired on ether doesn't mean it's isolated to a fuel problem (and yes, don't use it). Is it a 5-speed or automatic?

Is the Check Engine Light illuminated?
Are there any mods on the truck like a chip or tuner?
Is the Wait-To-Start light coming on normally?
Are all the underhood fuses good?
Is the oil level good?
Does the tach move when cranking?
Any white smoke out the tailpipe when cranking?
Wat's the fuel pressure when cranking?
What are the fuel tank levels and have you tried switching tanks?

Answers to these will get the folks here going. Cheers!

Ok so the truck is a 5spd manual, and no check engine light, super chips did install a tune on the pcm long before I got it. Fuses are fine, wait to start normal, oil barely registers on the dip stick but it’s been sitting for 2 wks and it’s getting close to 0 degrees so I’m not sure if I can get an accurate reading (I’m pretty sure it has to be warmed up to check)? No smoke when cranking, although tach does move when cranking. I will check the pressure as soon as I can I don’t have a gauge... front tank sending unit is out and I know it’s empty rear tank is over 1/4 full tho.

I noticed today after I drained the fuel bowl it’s no longer filling up so I’m not sure what would cause that? Thanks so much!

 

[Patrick Feeley]

I would get the oil level up a bit. FWIW, I always check mine cold and its right on the full mark. You could have a fuel restriction somewhere. Cheers!

 

[ArcticDriver]

Do you still have the Super Chips programmer.
I may be wrong but the Super Chips I have seen have a controller that saves the old tune and installs their tune and then you have to re-attach the controller to resave their tune before it will re-install the old tune.

Your old factory tune would still be saved on that one specific controller.

Kind of like a Bitcoin 😀

And it is definitely low on oil as you discovered.

Now about that word, “Never”...😉

 

[Craig Alberts]

Ok yes I borrowed a fuel pressure gauge when the problem first started and it seemed to be running at normal psi, I forget the exact numbers but I verified them via another forum. No the front tank doesn’t register and rear tank was half full, I was very aware because I was on a road trip when this happened and I had fueled up both tanks at the same time. I completely used the front tank and was half way through the rear tank when it finally went. What’s odd is today when cranking over I checked the fuel bowl and it now has almost nothing in it! Not what you mean by fuel tank selector valve I will look it up and check it. Thanks so much

I would bet you have got a stuck fuel tank selector valve...lots of times they get stuck and won't let the fuel flow from the tank to the fuel bowl.

Here is a post on how to test them... Test Valve

 

[Deiseldog]

There’s a chance that your fuel tank sending unit strainer has fallen off the bottom of the pickup tube into the tank and it’s just not reaching below the fuel level. After 160k on my 97 7.3, both strainers had come off and both the brass floats were filled with diesel. A waterlogged (diesel-logged?) float would also explain why your front tank sending unit isn’t working. The easy test would be to fill your front tank, switch to it, and see what happens.

 

[Steve83]

I just replaced both shower heads in my truck.

(click this text)


I could only see the pieces in the rear tank - the front fuel was too deep & cloudy to see the black pieces in the black tank.

(click this text)


Both my truck's floats are foam, so they were simply reused. If you have brass floats, they can be directly replaced with the foam one shown & linked on this page:

(click this text)