<hr style="color:#D1D1E1; background-color:#D1D1E1" size="1"> Ok guys I got one for ya

Got a 96 F350 <acronym title="Power Stroke Diesel">PSD</acronym> auto in the garage. Died on a guy driving down the road. Wasnt getting any fuel pressure. I tested it at the FPR. Ok so I replaced the pump, replaced the fuel bowl (found a hairline crack starting), all new rubber lines, popped the feed line off the selector valve and blew air through it to make sure it was nice and clear.

Here I am with still no fuel pressure. I can watch it fill the fuel bowl nicely. If I crack open the drivers side fitting at the rear of the head near the turbo I can watch it push fuel that seems to have pressure to it. If I remove a return line from the FPR it pulses fuel like I would expect it to. Yet still no pressure reading. Now I tried my fuel pressure gauge on my 94.5 and it bounces between 50-70 like I would expect.

I for the sake of variety tried a new <acronym title="Camshaft Position Sensor">CPS</acronym>, tried a known good computer, known good <acronym title="Injector Driver Module">IDM</acronym>, It does throw a <acronym title="Camshaft Position Sensor">CPS</acronym> intermittent code as well as an injector 1 low circuit code. The injector code I am not worried about as the truck has 260k on it and its beat. The <acronym title="Camshaft Position Sensor">CPS</acronym> intermittent code worries me a hair but the tach bounces, and when cranking there is white smoke coming from the tail pipe. Not a lot but there is some there

Found I had no HPO pressure and weak flow out of the HPO line

Rebuilt the <acronym title="Injection Pressure Regulator">IPR</acronym>. It was gummy but I suspect that had a lot to do with it sitting in the cold before I started working on it.

Put it all back together and got HPO again. Still no fire

So at this point I have fuel pressure (I think I do? gauge wont read on this for some reason but bowl fills up quickly and I get fuel out of the return lines. Should be enough to do something).

The HPO shoots to 500psi quickly and then spikes out to 3000psi since its not firing.

I keep getting injector circuit 1 low and cam position intermittent codes. The injector 1 code doesnt bother me so much as the cam position intermittent code does. But it has a brand new <acronym title="Camshaft Position Sensor">CPS</acronym>. I might take this one back and get another one. They are autozone ones but for this they will work.

I keep going back to the fuel side of things. I really need to get a reading on fuel pressure to feel better about it all

Anyone got any ideas?

 

I'm not sure on the fuel pressure unless you have a blockage by the schrader valve area? Just a thought, I'm really not sure.

As for the cps, I'd get a ford or IH one in there. There have been MANY cases where the parts store ones don't work. Check the wiring to the cam sensor for chafing too.

 

I am going to plumb in a real gauge today as soon as lowes opens so I can get fittings

I thought about that. I put that CPS into my other truck and it runs just fine. So I left it in there and tried my good one in the truck with no change.

I think you are right with the harness. I am going to check continuity from the CPS plug to their pins on the 42 pin connector.

 

Check the spring in the fpr
If its broke it can cause no/low fuel psi

 

Thats new, well rebuilt. When I noticed the bowl was cracked I put a new bowl/fpr in it and cleaned out the FPR including checking the spring.

What makes me wonder is its doing the same thing fuel wise as it did with the old pump and bowl. I get a much better fuel flow into the bowl and through the return lines with the new pump but still no pressure. Makes me wonder if I dont have injector o rings letting go? It would take a few of them but its possible

Biggest issue is I have no back story on the truck. I dont know how it was running before hand

 

This may be a dumb idea, but could you pull the valve part out of the schrader valve, like a tire, and crank it? It might be a little messy if you have pressure but if not you would clearly know you have a blockage.

 

Thats next on the list, Im a night shift guy so Im headed to sleep shortly. But when I get up I am going to dig into that

I want to pull the valve and plumb in a gauge. Although its the same symptoms across two pumps/bowls/fuel pressure regulators

 

That would make me think it is a possible blockage issue more than a mechanical issue. But I would be chasin my tail if I was in your shoes no matter what! Good luck.

 

If the O-rings were gone or going I'd think you'd be able to detect oil one way or another somewhere it shouldn't be. Nice clean fuel? Dipstick level stays constant? Wouldn't you also be losing HPO during the crank if they were that bad? I've heard of people having no start issues with almost brand new O-rings after not using Alliant branded.

Have you tried running it from a fuel can as well to eliminate tanks ---> engine as a source for decreased pressure? Here's a thread from not long ago where Jim experienced a similarish no start. https://www.ford-trucks.com/forums/1...one-to-me.html

 

Im getting solid flow into the fuel bowl so shy of it just being the worst fuel in the world I can rule out a tank issue. Although I should try a can of fresh fuel

I am not going to make it to the store tonight so no fuel gauge parts for me. Plus I dont think it would kill me to take a night off from this thing

 

Ok little update, narrowed it down to a crap fuel pump from the store. So I took it back and of course they have to order it. So it sits in my garage taking up space till they get another pump in

 

How did you isolate it to a bad new pump?

 

No pressure at the test valve on the FPR, So I unhooked the return lines and saw a dribble of fuel. That lead me to unhook the feed lines at the back of the head and saw the same dribble of fuel. While still watching the first stage of the pump fill the bowl like it should.

 

Well, that happens. Hopefully the new pump will take care of your problems. Just had the same problem yesterday with my 76. New pump, doesn't work.

 

We will find out in about 2 hours. Autozone opens at 9 so I should be home by 930 and have the pump in by 10.

Fortunately for my patience the owner of the truck doesnt want to go any farther if this doesnt fix it. I may continue to dig just out my own curiosity but it wont be a priority. Ive got other things to work on that will make me a lot more money