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Stumped on where to go now, '95 7.3Lt Powerstroke no start (SOLVED)

1K views 9 replies 5 participants last post by  dieseldogtom 
#1 ·
So I've got an early 1995 model 7.3lt Powerstroke with VIN engine code K. Just got this truck, it would only run for 15-20miles and then die. Would not restart for 30+ min afterwards, then run rough for awhile. So I'm new to working with diesels and thought this would be a great opportunity to learn. All I can say is I quickly got over my head.

So he is what I did to the truck..

1. Replaced all the injectors and injector cups. Pressure tested cooling system to 15psi after parts install. No fuel in cooling system. No cooling in oil.
Seems everything went well with this part.

2. Replaced HPOP and IPR. These were 94-95 version parts. Purchased Bosh pump with matching IPR from same source. Replaced worn looking hoses
while I was working on this. Using IPC port I was able to read I have over 1000PSI (only have 1000PSI gauge). I cracked open hoses while under pressure
to try and bleed out any air.

3. Replaced all fluids and filters. Oil, cooling and fuel. Do not have any signs of fluids mixing. I also pumped out the HPOP tank and refilled.

4. Replaced the IPC Sensor

5. Replaced the CPS

6. Replaced the temp sensor next to the water pump. (it had a minor leak).

7. Replaced both of the valve cover gaskets. Both left and right sides had melting of several of the glow plug connections.
When I replaced these I also installed new pigtails of the engine wiring harness. I soldered each wire, insulated the connection with heatshrink tubing.
Each wire was then ohmed with a meter from the end of each wire to the engine wiring harness connector. Verified wiring color codes with each wire
going to the correct device.

8. Replaced both batteries and the starter.

So, I have cranked on it a bunch of times, the engine sputters but never keeps running after the start stops.
First few times I cranked on it, fuel pressure only went up to 10psi. A few more times got it up to 20psi. a few more times its now to 40psi.
That just seems low to me, that fuel pressure should have come up alot faster then that. But I dont know.

Any guidance anyone can offer would be great. Thanks.
 
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#4 ·
Additional information: during cranking the engine sputters, TAC shows RPM jumps up to 500rpm. Fuel pressure seems to stay near 20psi until I've gone thru 3-4 15sec start attempts. It will reach
40psi eventually. After sitting for 5 min I see the pressure slowly drop from 40psi to 20psi and then hold there overnight. Is this normal? I would think the fuel pressure should go up to 40psi quickly and stay there. Is this an issue with the fuel pump or the fuel pressure regulator? Or maybe something else?

I still see no mixing of liquids. No fuel in oil or coolant. No coolant in fuel or oil.

ideas?
 
#5 ·
So, I have replaced the mechanical fuel pump and cleaned out the regulator. Now have 55-60psi after three short crank attempts (needed to work the air out of the system) . Looks like there was a fuel delivery issue.
Still have not had a complete start. Will seem to catch but dies within 5 secs after starter is stopped. It is smoking a lot more now then it did before from tailpipe. I am up to the 5th start attempt.
I crank on it 15-20sec and then let sit for 5min or so. Want the batteries a chance to recharge (have a 200amp starter/charger) and the starter to cool off so I don't burn it up.
I know my HPOP is at a minimum of 1000psi and now my fuel is at 55-60psi, I would think it should start.
 
#6 ·
You may still have air in the HP oil system (it usually takes some decent hard runs to get it all out). What color is the smoke from the tailpipe? You might want to plug in the block heater for a few hours prior to starting attempts. Is the CEL illuminated? Cheers!
 
#7 ·
My direction today was to revisit the wiring. To ensure everything was correct. Using an ohm meter, i checked each injector at the cover gasket. Then back to the engine harness connector and finally at the IDM. I did find I had corrosion on many of the pins. Looks like the connector leaked at some point. I was able to clean up the pins and connector using contact cleaner.

I also looked at each sensor and attempted to test them based on sensor type. If I had a second sensor, I would compare the readings. What I found was the "new" cam position sensor did not read the same resistances as the original. With my ohm meter on 20meg scale, the original senor would go from lower resistance and quickly go up, this was from the common wire (BR/W) to each of the data wires (LBL) and (DGR). This told me there was something different about the "new" sensor. So I re-installed the old one. Truck fired right up. Went back to Ford dealer and got another "new" sensor and installed it. Truck is running fine now.

Moral of the story is that even "new" parts may not work.

I don't regret all of the other work I did. Any one of the earlier issues I found could have been a problem down the road.
 
#8 ·
Wow, Another CPS nightmare story!
I think we need to find the engineer/designer that developed these CPS thingys and...
Did I hear somebody say ..."Get a Rope" LOL
That CPS was the first thing I thought of when I started reading this thread but then I saw Replaced CPS.
I''m glad you got it resolved & I am sure if felt REAL GOOD when it fired right up. Just to bad that you had to get a faulty "new part" that screwed up your whole plan. It's tough to diagnose issues when the NEW PARTS you put in are bad from the start. Not many of us take our new parts out of the box & start checking them with Ohm meters before we install them. There's a certain amount of faith that because it's new it should be expected to perform at it's best level. DDT
 
#9 ·
Not many of us take our new parts out of the box & start checking them with Ohm meters before we install them.
Not many of us fix our trucks faster & with less cost/confusion/frustration than those who DON'T check every new part. ;)
There's a certain amount of faith that because it's new it should be expected to perform at it's best level.
Maybe many of us will give up on that soon... Because IME, new parts are generally LESS-reliable than originals. FAR less.
 
#10 ·
Yep Steve, Sadly,These days that seems very true. Except for the CPS debacle! Seems the aftermarket products (at least a few of them) are better than the OEM. I keep reading posts about the recall of the CPS where guys brought their truck in because it was either stalling out (like mine was) or running poorly... Dealers R&R'ed the CPS with what I keep reading was a Gray one. Then their trucks maybe ran better or maybe didn't. Then they wish they had their original OEM CPS back. I never quite understood this since it presumably was giving them trouble in the first place. (Maybe just less trouble than their replacement one is giving them). So far I consider myself lucky. I didn't opt for the FREE CPS from a dealer. I'm TERRIFIED to let them get near my van! So I just coughed up the $39.99 to get a new aftermarket CPS from www.dfuser.com. That was 30,000 miles ago in 2014. Has not stalled or skipped a beat since then! And if I had any brains, (I don't), I would probably get another one as a spare. But I like liv'in on the edge! LOL
 
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