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Any powerstroke mechanics in the house?

k20

k20

3/4 ton status
Joined
Sep 9, 2001
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Location
Mineral Springs, NC
Hey guys, been working on my dads 96 7.3 powerstroke. Its only got 90k miles on it (it sits way too much). I have posted on a couple p-stroke forums and havent gotten a whole lotta help, so figured Id see if anyone here had any ideas. This is gonna be a longggg post, but figured Id get all the info out there.

Last week I drained both fuel tanks (fuel was nasty), treated them, replaced fuel filter and it ran without a hitch for me for several hours. Left it with him, and when he went to drive it yesterday, no dice, wouldnt fire. Just spun over. He tried it 4 or 5 times and then drove his other truck to work. Now it was between 35 and 40 degrees yesterday morning.

While I was checking the GP's I noticed a fair amount of fuel in the lifter valley. I thought I cleaned it all out last weekend after doing the fuel filter, but maybe not. Anyway, washed it all out and so started the truck to dry it out. Let it idle approx 15 mins while I picked up tools, etc.

Got in it, backed out of the driveway, turned the corner and got on it hard. Made it to third gear and it was like the throttle just quit working. It quit pulling wouldnt rev, nothing, pushed the clutch in and it cut itself off.

Hit the key and it turned over for approx 5secs before it caught and after that it ran just fine.

Drained the filter housing again just to see if any water had collected since the tank draining. So I had it idling and was rinsing out the lifter valley again and when I got up behind the HPOP, and was spraying down the truck kinda stumbled. I quit spraying and started looking.

From the passenger side, I reached down towards the HPOP (on the pass side there is a large hex headed plug), and when I pushed the high voltage (red wrapped) harness out of the way, the truck shut down just like somebody turned the key off. Went around and it fired right back up and shut right back down. Hit the key again, blipped the throttle and it idled just fine. Went back around and wiggled every wiring harness in site and it wouldnt do it again.

I was degreasing the engine to make it a little easier to work on. When I was rinsing it off, I decided to fire it up and see if I couldnt find out what the wire wiggling/cutting off was about with the shutdown. So its idling along and the second the water hits the CPS, it shuts down like you turned the key off. It will refire as soon as you turn the key, but if you hit the CPS with water its dead.

Sooooo, yesterday I changed the CPS & the glowplugs out. While I was at it also changed the oil (it was about time anyway). Now it will actually start when its sub 50*, power seems up slightly. However, again, I had it sitting idling, warming up while I was picking up tools and it shut off
ohnoes.gif
. So I hit the drain valve, get just a little water/nastiness out. So I take off the 2 bolts that hold the regulator on the side of the fuel bowl and there is alot of sludge (algae looking crap) stuck to that screen.

Cleaned it off, put it back together and then it just wouldnt fire. Turned over and over and over, let the starter cool off and did it again. Had to repeat that 3 times, then it fired up and ran fine. Also didnt notice any smoke while it was turning over, but its hard to tell its windy out and its got the dually fenders blocking a straight view in the mirror. It should not take that long to reprime, I didnt let but maybe a few ounces out when I drained the bowl and hardly anything came out when I took off that regulator.

This morning it was 30* (what happened to fall)? Anyway before I tried anything, popped the hood, checked the HPOP resevoir, its full. Hit the key WTS light came on, when it went off, turned the key it fired right up.
biglaugh.gif
It ran at a slightly elevated idle (approx 900) for about 45secs. Then the tone of the engine changed a little (almost hollow sounding), check engine light popped on and engine died immediately (those 3 things happened in a span of about 5 seconds). Turned key, restarted. Same deal, except it ran slightly longer, about a minute. Third time it only ran for about 30 seconds then died with no check engine. Once more and it ran for about the same amount of time except it didnt go into the elevated idle, it just ran at its normal 600rpm.

Checked HPOP again, its still full, so atleast to what I have read the ICP isnt telling the IPR to dump all the oil due to high pressure, and the IPR isnt sticking and dumping all the oil, or could those still be culprits?



Well thats a lot of cutting & pasting to get the whole story off one of the p-stroke forums, so if something doesnt quite make sense, its probably b/c of the cutting and pasting. Anybody have any ideas for what I should check next?
 
You really need to get a scan tool on it and see what the computer is seeing but it sounds like the oil pressure sensor is on its way out.
 
Sounds like it's time for a cam position sensor. ONLY buy the Ford one! The others are junk. Ford has revised their cam sensor about 50 times and it appears they finally got it right....
 
Yeh I replaced the CPS yesterday when I did the glowplugs, used the ford one...still no dice....who the hell thought it was a good idea to fire injectors with oil anyway?
 
Yep, scan tool is really gonna help, but here are a couple of ideas. Most of which I suspect you have already heard on the other forums.

First, I suspect you may have a fuel contamination problem. If you found the crud growing on a filter, then its all through the system.
The poison they sell as an additive will clean it out, but when it dies and breaks loose, its headed for the filters.
Make sure when you get it cleaned out, that you put some of the additive in with every fillup.
It sounds like its sitting too much and the stuff is growing. I treat the 500 gallons in my genset tank heavily when I fill it, and I'm going on 3 years so far and its still nice and clear.
Dyed, of course, but clean.

I suspect that your second problem is still the CPS. One of the things I like best about Ford, is that they do everything really well.
When they build a good vehicle, its a great one. When they screw up, they do a good job of that too.
Not only is the factory CPS overpriced junk, but some of the "improved" ones are worse.

From the little experience I have had with Powerstrokes, the International CPS is the way to go.
Not only does it last and is reliable, but almost everyone who puts one on says the engine runs better and gets better mileage.

There are two versions, depending on the year and/or serial number of the engine. Since yours is a 96, you want the older version. During 97, a change was made in the material of the contacts, and it happened in mid production. So you have to check the engine serial number to get the right one.

But, either one will work, its just a change between tinned or gold plated contacts and you want to match them up to prevent possible corrosion.

I can probably run down some model numbers if you need them, but its a pretty common mod. I imagine the numbers are available in lots of places.

Plus, having it die when you moved that wire is suspicious even though it didn't do it again. I would keep investigating that angle.

Almost forgot. Supposedly the Tach on that model is related to the CPS. If it fails, the Tach quits reading.
Plus, when you are cranking and its not firing, after a few seconds the Tach needle should start bouncing.
If it doesn't, the CPS has failed and is keeping it from running.
 
Yeh I know it had a fuel contamination issue. I drained the tanks and added biocide and replaced the fuel filter, so that angle is being taken care of the more I run it.

And the CPS I replaced it with was the dark blue/purple one, ford p/n F4TZ-12K073-C which is supposedly the same as the international one, atleast from what I have gathered on other forums.

Also when it just cranks the tach does read, but I did find posts where the cps fixed problems but the tach would still read so who knows.

But I did just have a little fun a few minutes ago, here is a copy and paste off the ford forum...maybe it will give yall some more ideas


Drove it up to the store about a mile away, went in, came out everything is fine. Coming home, coming away from a stop sign, I was getting on it pretty good and about the time I hit third gear, it coughed and almost shut off. Well, it was fine, up until the next stop sign. As I was slowing down for it, no warning, just boom, dead. Hit the key and it just spins over. Did that several times, get out, open hood, wave idiot around who doesnt know what hazards and a hood open means, hit the fuel drain, and nothing comes out?!?!?

Nothing, no fuel, no water, all I hear is a slight sucking/gurgling sound. Walk home, grab a can of diesel and toolbag, walk back to truck, take lid off the filter and as Im threading it off I hear more gurgling and when I get it all the way off its full of fuel and the fuel drain works.....get in hit the key and it fires right up......

Seriously guys.....what in the name of all that is holy is wrong with this thing.....when its running if you barely even crack the fuel drain it shoots a geyser out (I have the redirect tube taken off so I can see the fuel come out the drain easier), so I know the fuel pump is giving it good pressure, but its like when I got on it away from the stop sign it sucked the filter housing dry and thats why it died, almost like a vapor lock issue.
 
100% bone stock, I replaced the lift pump about a year or so ago though, stock replacement though
 
Are you sure the fuel pump has enough pressure? When my pump went bad, it would run at idle but as soon as I stepped on the gas it would die.
 
Sounds like a wiring problem with the electric fuel pump....Its getting reverse voltage every once and a while and sucking the fuel back to the tank.....:D

But, seriously, that is almost certainly a fuel supply problem. There was a vacuum on the filter.
I've got a bad feeling the tank is going to have to come out. I'm trying to do some other stuff while I type this, so I'm a little distracted, but if I remember right, you have a lift pump in the tank, then that filter, then the injector pump or boost pump, right?

Well, if so, then the tank pump either quit, or something stopped it up. That filter should have had pressure on it.
 
Its got dual tanks so that makes it worse if I gotta drop the bastards. Anyway, they each have 10-15 gallons.

Also it has a mechanical fuel pump in the valley on the engine, no electric pump. If its running and you crack open the water drain its a large amount of fuel at pressure coming out, so I would say its got pressure (doesnt have a gauge), now whether it has volume I cant say.

However, why would it then proceed to die when its idling and Im doing something else, like it was yesterday?

Almost wonder whats on the bottom of the pickup in the tank.....like if its sucking something up, plugging it and dying....I may go out and switch tanks, run off the other and see what it does.
 
OK, I have not worked on many of those, and when I have, its just usually one thing and I don't get too far in.
The mechanical pump is on the tank side of the filter? If so, then its not pumping for some reason. The only way for vacuum to get to the filter is if the lift pump is not working and the injector pump is sucking it dry.

If the filter is on the tank side, then it would be something in the tank for sure. With the filter after the lift pump, it could be either.

Definitely switch tanks.
Many years ago we had a dual tank route truck that would only run intermittently on the back tank.
Our mechanic tried everything. It might sit there and idle of an hour, or drive for miles.
But, sooner or later it would quit.

Finally dropped the tank, and found a piece of paper in it. Just drifting around. Every so often it would get over the intake.

Never figured out who did it.
 
Well switched to the rear tank and no problems so far. Took it for the same spin as the one this morning that sent me walking. Drove it like a racecar, then drove it on a big loop and lugged it down, drove it normal, then racecar again, and no issues......shut it off, hit the drain and big stream of fuel. Im gonna switch back to the front tank and let it sit and just idle for 10mins or so, shut it down and hit the drain and compare the drain volume. I think we may be on to something, oh, and Ive already gotten more replies here than on the p-stroke forum that I posted on a week ago....

Anyway, the system is set up tank--->selector valve--->fuel pump----->fuel filter--->injectors
 
With that setup, it could be either the pump or the tank. Or selector valve. But I'm guessing either tank or valve.

There are a couple of versions of that valve used by different setups. I have seen one that is switched by fuel pressure from the tank. To select tanks, you switched the different intank pumps on.

Not that way on yours, of course.
Then, I have actually seen one that was motor driven. Odd.
Most of them are solenoid nowadays I think.
But of those, there are a couple of types. One has a solenoid on each end, and one is spring loaded with a constant duty solenoid.

Its possible that it is not switching all the way over due to algae build up in the valve. There is only supposed to be two positions, but half-way might block the ports.

I gotta throw this one in, because I see all the weird stuff. Not likely in your case, but if it quits on the front tank again, try opening the filler cap.
Might have a plugged vent.
 
k20 said:
Yeh I replaced the CPS yesterday when I did the glowplugs, used the ford one...still no dice....who the hell thought it was a good idea to fire injectors with oil anyway?
Click to expand...

Didn't put Cps and cam sensor together in my head :doah:
 
I had a 96 F-350 with the power stroke and the ONLY problem I ever experienced with it was the rear tank fuel pickup screen broke a little plastic coupler. That dropped the screen off and the truck would run out of fuel at 1/4 tank. You may try adding five-10 gallons to one of the tanks and give it a try.
 
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