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Discussion Starter #1
I have a 1996 7.3 that would first randomly stop on the road as i was driving it and would restart after like 5 minutes; then after a couple days it would only start after like 20 cranks. Then after a week it would only start after i replaced the CPS and ran fine for another week. Then after 2 weeks it ran limited to about 15mph or so! and now it just wont start at all and i have tried replacing the CPS again and no luck at all


Im getting wait to start light
my tach is moving upon cranking
Fuel bowl seems to be getting refilled
I unplugged icp with no results
I changed my IPR with no results
 

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Mine died in an intersection in Yuma and had to be towed back home. Turned out to be the PCM. Replaced it and all was good again.
 

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What's the actual fuel pressure while cranking? Any white smoke while cranking? Is the CEL illuminated? Check your oil level. Cheers!
 

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I agree with Patrick, check your fuel pressure. Seams to be getting fuel doesn't work on these engines.
 

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Discussion Starter #5
Thanks for the replies, no CEL

White grayish smoke comes out of tailpipe

How can I check fuel pressure as there isn’t much room to fit a tire gauge on the valve

reason I said it’s getting some fuel is it’s filling the fuel bowl slowly not very fast
 

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You can get a air pressure gauge on the schrader valve on the drivers side of the fuel filter housing. Just wrap it in rags or you may take a diesel bath.

At idle you should be seeing 50 psi + any less and odds are the fuel pump is on it's way out.
 

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Discussion Starter #7
It has a new fuel pump but it won’t turn on so how can I check the psi? Also how do you even fit the gauge on the valve as the engine hook is in the way
 

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If you use a pencil type air gauge that is angled it will connect onto the valve good enough to get a reading.

Not running you should see around 20 psi while the engine is turning over.
 

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I had a similar problem some years back. Seems a field mouse had eaten the insulation off the CPS loom a ways back from the sensor and it was causing an intermittent short.
 

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Discussion Starter #10
How did you find the wire short? Was it against the engine block?

I just put a tire gauge on my fuel valve and crank the engine over with it on and I’m not getting any fuel pressure whatsoever. What could this mean?
 

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No fuel pressure can be:

Fuel pump, supply lines, tank problems.

Is there fuel in the filter housing? If you just depress the valve on the filter housing does it squirt any fuel out when someone is turning the engine over?

How much fuel in the tank that you are running on? If it is below 1/4 try switching tanks or putting 5 gallons of diesel in it. If it starts then it is quite likely the foot or the line in the tank is bad where it is sucking air.
 

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Discussion Starter #12
It has a newer fuel pump but could it really go bad that fast?

Supply lines are also newer blue ones

there is fuel in the filter housing and when I press the valve fuel does come out; I had the bowl removed and with my hand over the main supply line off the fuel pump it built lots of pressure and sprayed when it cranked over so I’m surprised I’m not getting any reading from the fuel valve!

I had about 1/4fuel in the rear tank and added 10 gallons or so in the front tank so it has from where to pull fuel from

I’m stumped big time
When I crank the engine over I’m getting smoke out the tailpipe also
 

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The fuel pump on these trucks is a two stage fuel pump. It draws fuel from the tank and then sends it to the filter housing on the low pressure side. It then pressurizes the fuel up to 55-60 psi to be sent to the injectors, the unused fuel is then sent back to the FPR fuel pressure regulator before it goes back to the tank. This is where you took the fuel pressure. No fuel pressure at the FPR says that the fuel pump isn't pressurizing the fuel to send it to the injectors and back to the tank.

I have seen rebuilt fuel pumps be bad right out of the box, so unless the pump was a new one you really won't know.
 

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Discussion Starter #14
Hmm I understand but that why I wrote this

I had the bowl removed and with my hand over the main supply line off the fuel pump it built lots of pressure and sprayed when it cranked over so I’m surprised I’m not getting any reading from the fuel valve!

I can go buy a new fuel pump and see if that’s really the problem but I’m really not sure how can I test if it is a fuel problem or a glow plug problem?
 

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You had your hand on the low pressure side and not the high pressure side.

The low pressure side pulls from the tank and sends it to the filter housing.

The high pressure side pulls from the filter housing and sends the fuel to the injectors.

Look at the attachment in my above post

Sent from my SM-J737V using Tapatalk
 

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Discussion Starter #16
I understand now thank you; would you go ahead and have the fuel pump changed out?
 

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With zero fuel pressure out of the FPR I believe that I would replace it with a new pump.

Do you know if the fuel pump that is on it now was a new or rebuilt one?
 

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Discussion Starter #18
Brand new fuel pump; I just put the angled tire pressure valve on the stem and had someone crank the engine and I’m not getting any pressure reading at all yet I’m getting fuel spray when I take the gauge off the stem
 

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I'm not sure then. You should be able to get a reading on a tire gauge.

When you turn the engine over do you get any smoke out of the tailpipe when it is cold?

When you turn the key on do you get the warning lights and the WTS light?

Beyound these ideas you might need to get a scanner that can read Fords live data to see what is going on with the electronics.
 

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Discussion Starter #20
It’s not a lot of fuel coming out of the valve stem but there definitely is fuel

just don’t want to throw parts at it and time when it could be the glow plugs or something else

yes every time smoke comes out the tailpipe

WTS light and the rest come on when ignition is set
 
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