Quits when warm 7.3 1995

littlerobert1983

New member
Joined
Apr 24, 2017
Messages
37
Reaction score
0
I replaced glow plugs then drove truck to put fuel in it and ran completely out. I know not healthy by any means,fuel bowl had setiments and dirt in bottom. Cleaned fuel bowl and filled fuel bowl and installed new filter. Truck will drive around block and quit once it's warm. Have replaced cps ipr and icp to no change at all! How do I check fuel pressure on this? Also do you think the lift pump could be out bc when it quits and I remove filter the is only about an inch of fuel in fuel bowl. Truck runs great at idle but under load it will stumble and drop rpms until it just quits and then it's hard to start. There is white smoke coming from exhaust. I do not have access to any scanner so that is ruled out to use at all. I have also ordered new idm 120 volt coming I'm mail just to make sure it's not that. Could you plea see help me with this issue I don't know what 3lse to do at all. Truck has no programs and new injectors 12,000 miles ago and new turbo installed a same time. Please help!

Sent from my SM-S920L using Tapatalk
 
Last edited:

jschildm

Member
Joined
Jul 26, 2011
Messages
351
Reaction score
3
Location
Southeast Iowa
The fuel bowl not being full after it has been running seems like a red flag to me. There is a schrader valve that can be used on the side of the fuel bowl to check fuel pressure. The mechanical pumps are a two stage pump, one side pulls fuel into the fuel bowl, the other side pushes higher pressure fuel (~50 psi) to the injectors.
 

mandkole

Active member
Joined
Jan 14, 2012
Messages
2,303
Reaction score
2
Location
Northwest
If the bowl quickly fills with cranking pressure, lets assume that the pump is working for the moment. Screw a gauge into the Schrader valve-- the gauge will bounce due to the mechanical pulse but 60 psi is enough for decent operation. If you pull the cap and filter out of bowl, the bowl will be part full (displacement of the filter assy). Half full with filter inside is not normal. Any fuel leaks? does it smell of fuel under the hood after driving?

Does the truck run well when cold or barely warm? If you accelerate it cold, does it pull normally?

Other red flags;
-dying with hot oil is often an HP oil related issue due to oring leakage or pressure loss somewhere. Thicker cold oil will perform better and hold pressure then dies when hot. Get it on an OBD2 reader to determine ICP at idle and under demand. You need 500 psi to idle, and it should rise as pressure is commanded up towards 2500psi on stock tuning.

-I read that you ran it out of fuel. You could have broken components, or debris, in the fuel pickup assembly in the tank which is preventing good flow under higher demand. May need to blow out the supply line to dislodge any debris and/or possibly create a temporary clean fuel supply and tap the system into it. if you get improvement in performance, your issue is in the tank.

Try to provide feedback to this first, then move forward.
 

littlerobert1983

New member
Joined
Apr 24, 2017
Messages
37
Reaction score
0
If the bowl quickly fills with cranking pressure, lets assume that the pump is working for the moment. Screw a gauge into the Schrader valve-- the gauge will bounce due to the mechanical pulse but 60 psi is enough for decent operation. If you pull the cap and filter out of bowl, the bowl will be part full (displacement of the filter assy). Half full with filter inside is not normal. Any fuel leaks? does it smell of fuel under the hood after driving?

Does the truck run well when cold or barely warm? If you accelerate it cold, does it pull normally?

Other red flags;
-dying with hot oil is often an HP oil related issue due to oring leakage or pressure loss somewhere. Thicker cold oil will perform better and hold pressure then dies when hot. Get it on an OBD2 reader to determine ICP at idle and under demand. You need 500 psi to idle, and it should rise as pressure is commanded up towards 2500psi on stock tuning.

-I read that you ran it out of fuel. You could have broken components, or debris, in the fuel pickup assembly in the tank which is preventing good flow under higher demand. May need to blow out the supply line to dislodge any debris and/or possibly create a temporary clean fuel supply and tap the system into it. if you get improvement in performance, your issue is in the tank.

Try to provide feedback to this first, then move forward.
I currently have an electric pump hooked up and run to the high pressure of the mechanical pump,then to a 5 gallon can to supply clean fuel to see how it runs under load brake while pressing gas after motors warm

Sent from my SM-S920L using Tapatalk
 

littlerobert1983

New member
Joined
Apr 24, 2017
Messages
37
Reaction score
0
I currently have an electric pump hooked up and run to the high pressure of the mechanical pump,then to a 5 gallon can to supply clean fuel to see how it runs under load brake while pressing gas after motors warm

Sent from my SM-S920L using Tapatalk
If truck is cold it has plenty of pull and runs good even idling when warm it runs good. When under lo ad and gas pedal is pressed and brake held it will stumble until it quits running. That's why I'm leaning towards it being a fuel issue. The fuel bowl has about an inch or inch and a half of fuel in it when the filter is removed.

Sent from my SM-S920L using Tapatalk
 

mandkole

Active member
Joined
Jan 14, 2012
Messages
2,303
Reaction score
2
Location
Northwest
Ok good, it runs and starts well when hot. Yeah, work thru the fuel system for good supply and pressure.
 

littlerobert1983

New member
Joined
Apr 24, 2017
Messages
37
Reaction score
0
Ok good, it runs and starts well when hot. Yeah, work thru the fuel system for good supply and pressure.
The tank selector valve was hot and seems to be letting return fuel into the front tank at an alarming rate now to the point it comes out the filler neck. The truck will not start when it quits until it cools way down and starts hard and fuel bowl has to be refilled. I believe the selector valve is caught between tanks because the fuel gauge is way over full now and being on front tank it's never been that far over full before. Does anyone know how to bypass the selector valve since it don't have a rear tank but only the front tank at this point in time until I can buy an auxillary tank.

Sent from my SM-S920L using Tapatalk
 

boggerr

New member
Joined
Jun 20, 2013
Messages
243
Reaction score
0
Location
Barnegat, N.J.
I'm not that familiar with the OBS selector valves but if you don't have a rear tank all the fuel has to go to the front tank. Did it become overfull from running it off a gas can?
What kind of electronic pump did you use? Is it enough to supply when the engine is under load?
 

littlerobert1983

New member
Joined
Apr 24, 2017
Messages
37
Reaction score
0
Anyway way you can check fuel pressure?
I'm using a diesel micro electric from Mr gasket,it's green it says 7-10 psi. Yes it became over full when hooked up to the gas can. I installed new idm and bc all the truck will do is crank over and not try to fire or hit now. I don't know what is going on with the truck now it seems that it's getting worse instead of better

Sent from my SM-S920L using Tapatalk
 

littlerobert1983

New member
Joined
Apr 24, 2017
Messages
37
Reaction score
0
Ok good, it runs and starts well when hot. Yeah, work thru the fuel system for good supply and pressure.
Truck will not start until it cools down for 20 minutes to an hour now 2ont start c at all even with the icp unhooked

Sent from my SM-S920L using Tapatalk
 

boggerr

New member
Joined
Jun 20, 2013
Messages
243
Reaction score
0
Location
Barnegat, N.J.
That fuel pump is not supplying enough.
Sounds like you have a fuel pump problem. I would start with getting a mechanical fuel gauge on it and see what kind of pressure you're getting.
 

Latest posts

Members online

No members online now.
Top