99 Ford F-350 7.3. This truck started up fine then 2 min. down the road started to miss. Parked the truck replaced the CPS, new Fuel filter and put some PS 911 in the tank. Now it starts runs rough (misses) then dies. Still have the same problems can anyone help. I was thinking lift pump.

 

When you restart the engine does it fire off on all 8 then after a minute or so drop a cylinder or does it fire and begin missing immediately? Any smoke from the tail pipe, if so what color? Any knocking or banging coming from the top end? When was its last oil change?

 

This is just a guess but it sounds like it may be the high pressure oil pump that fires the injectors. I've heard that the oil you use in the P.S. makes a difference, did it have an oil change lately and if so with what? I know it sounds stupid but some oils can foam in the system and this causes a lack of hydraulic pressure to fire the injectors. It's no wonder the HEUI system has been replaced. A hardcore powerstroke guy might correct me but I'm just telling you what I've heard. I hope it helps.

 

Not sure if the '99 had this issue but I would check the injector wiring harnesses. A buddy of mine with a '99.5 did the same, misfirings, stalling, etc and the dealer had to replace the injector harness.

MikeyB

 

Always maintained. Smells like unburned fuel. Tried it this morning now it does not start

 

Is there a significant oil leak on the top of the engine or a lot of oil in the engine valley? It does sound like an oil pressure issue. A leaking hpop will cause an extended crank to start and not enough oil feed from the lubrication oil pump will starve the hpop creating a no start. Also air in the system will produce similar symptoms. Are there any fuel leaks?

I can tell you this with certainty, ULSD is known to degrade older high mile fuel system o-rings, I have been changing fuel line sealing rings on ALL my I/H trucks because of leaking issues.

Instead of chasing our tails trying to diagnos this lets follow and isolate systems here.

1- make sure you have no significant fuel leaks.
2- remove fuel filter cover and then have someone turn the key on but engine off and make sure you have fuel filling the bowl at a moderate rate.
3-if all above is ok then move to the hpop system.
4- make sure the hpop is full of engine oil, there are plugs on the back of the pump for this.
5- if no oil in hpop than fill with oil then attempt to start, if it starts than dies do not attempt to restart, reinspect for oil in the hpop if no oil look for oil leak

Try what I posted up to this point and repost what you find and whatever you do DO NOT use either to fire that engine, if you must use a starting aid use WD-40.
Good luck, Tim

 

As some one else also mentioned check for chaffing wiring at the back of each head at where the valve cover meets the cyl head. If you find no chaffing then remove and inspect the plugs at the same location, I have seen broken pins there creating no start issues as well.

 

Yes they do, just did a 99 last week

 

Fuel filter bowl doesn't fill up when I turn the key in the on position

 

On my 97 and I'm almost certain that the 99-03.5, 7.3's have cam driven fuel pumps. You have to crank the engine to make the pump fill the bowl.

 

99+ PSDs have electric fuel pumps.

 

Good Advice. I'm thinking HPOP or injector harness too. Also, I don't think that WD-40 helps anymore. It was the propellant that burned, not the oil & a couple of years back they changed to a non-flamable propellant.

 

Thanks for the help

 

No problem - just post back after you fix it & let us know what the problem was.

 

Not being a Ferd guy, and I don't know what year it started, but I heard them Powerstrokes have to have oil pressure before the injection pump will deliver fuel to the injectors. Bad Sensor? or relay?

Dave