We have a 99 F450 7.3 rollback. The truck has been running very well untill about a week ago. on the way home from a car auction we started to lose power. We limped in to a truck stop to check out the fuel filter. could not get the top off! We sat for about 30 min truck started fine ran good and we headed home . About half mile from home she died again. Got it restarted and limped home. Things we have done.

replaced fuel sender in the tank and cleaned tank
replaced elec fuel pump and new fuel filter.
dealer replaced CPS
fuel pressure sensor reg rebuilt

Truck would run fine for a short while and then lose power and die. When running like crap if you give it frull throttle it would blow white smoke. I can't believe its the turbo because when running good has plenty of power usually turbo works or not! No smoke when running good! Now she is down again and I am at wits end trying to fig out!!! Open to all ideas! Thanks

Smokie

 

When it is running like crap is it missing or shaking or firing on all 8?

 

Try shaking the plugs that go to the under valve cover harnesses while it's running. If you notice any changes, then you have found your problem. Another possibility is the wire connection to the IPR. The tin nut on there is known for coming loose.

 

Please forgive my ignorance, what is the IPR??? I also have a 1999 F450 with a similar problem. I have already checked the harnesses under both valve covers. They were a little loose, but weren't the problem. My SES light is on as well, but I'm trying to avoid paying the $400.00 for the code reader and software.

Thanks...mike

 

injection pressure regulator....behind and under the fuel bowl....more on the drivers side.

 

Yes there is some missing ! But the feeling is for a better discription like slowly turning off a faucet!!! It justs runs down and quits>

Smokie

 

Thank you....I will check that tonight.

 

How is the oil level? Maybe a HPOP problem?

 

Have you checked the under valve cover harness?

 

Have not checked harness yet! I was also just told that there is fuel in the oil ? So now what? maybe injector bad? We are going to change oil Maybe the visc on the oil maybe to thin? I believe the HPOP opens and closes injectors or am I all wet?? Thanks for your replys !! What is your view on the turbo? think its bad ? The truck has 187K on the meter!


Smokie

 

In my experiences with the larger diesel engines in the military, when a Turbo goes, you will have lots of smoke rusulting from oil commingle from the Turbo, and it won't be intermittant. But, they are easy to check. With the engine off and cold, look for oil in the in the intercooler tubes. Also, there should be no, or very little end play in the Turbo fan and it should turn freely.

 

Turbo is fine. Is there any oil or fuel in the coolant degas bottle? sounds like an injector gets stuck open. if you find oil in the degas bottle then you are probably looking at a cracked injector cup.

 

Any chance the previous owner (if there is one) put a small inline filter that may have been overlooked durring all of this work?

Had a similar problem on mine, turned out to be one i put in and forgot about.
It did however cause the fuel pump relays below the radio to rapidly engage / disengage.

 

Duh! where that degas bottle at?

Smokie

 

degas bottle = coolant reservoir............ it where the antifreeze go.