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7.3 almost dead, runs rough, no power

42K views 32 replies 7 participants last post by  Mikey's250  
#1 ·
Had to get it towed home last night. Me and my gf went a few miles down the road to get a movie, running fine , pulled in the parking lot and it had a very small lope to it. Shut it off, went it for 5 mins come back, checked oil just in case, started it and lope got worse immediately and when I starting out of the lot truck started shaking and loping hard like it was running on 6 cylinders. I stopped and checked to make sure my chip was in good and no change. Decided to try and limp home. Truck would barely go 15 mph and would no pull up a very small hill, pulled over, and had it towed home. I think Im gonna try to borrow the scan tool from advance and see if it will tell me anything since advance auto is the only place open today:dunno:

So what do yall think? Is this a CPS problem? Im thinking its an injector(s) issue, like one went out and I lost oil pressure to the others?

I dont think its bad fuel because I have 300 miles on this same tank and its been running like a champ. And oil was change 1000 miles ago(rotella), fuel filter around 6000 miles ago.

Thanks in advance:thumb:
 
#6 ·
Thanks Mang. Im hoping it something like this and not more serious. How long does it take to get the valve covers off? And I was thinking I might do a buzz test if the scanner at advance can do it
 
#5 ·
One of the known issues with our trucks is a loose UVCH (Under Valve Cover Harness) connector. If this connector comes unplugged a little, it looks like this.

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Since that plug connects the wires going to the fuel injectors, when the plug becomes loose, the injectors on that side stop working and your nice powerful V-8 Powerstroke becomes a 4 cylinder.
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International (who made our motor) realized this was an issue and developed a plastic shim that slides under the locking tab to keep the tab engaged and prevent the connector from becoming loose.

Turns out a US Quarter is the correct thickness and width to act as a shim for this connector. The top of the quarter has to be ground down so the valve cover fits back on, but add a quarter to each side like this

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And you've just invested 50 cents to keep your truck running well. Hence the 50 cent mod.

Also, if you pull the valve covers, then you should also re-torque your rocker arm pedestal bolts, circled in red, to 20 ft-lbs

and your lower injector hold down bolts, circled in blue, to 120 in-lbs, note that's INCH - lbs. They tend to work a little loose over time and the engine sounds much better after you tighten things up (unless you've got a tuner).

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Heres a GREAT post that shows how to do it and torque down the rockers, too. :thumb:
 
#22 ·
Injector control pressure sensor I believe.

Yes I have fuel haha Still got around 100 miles left on this tank.

I forgot to say that after it got home I started it and gave it some throttle and it pour black smoke
 
#27 ·
Pull the valve cover and check the harness. That is the most common problem from what you are experiencing.

If those are both nice and snug, not melted either, build yourself a fuel pressure gauge and make sure you are running over 52 PSI of fuel pressure. If you aren't I would be doing a fuel filter and double checking the pump.

I had an issue like this with my old truck, it was somewhat out in left field, I had an injector go bad and over pressurize the fuel system from the pressure in the cylinder. It made some very foamy fuel in the PS head and I was basically running on 4 cylinders. Pain in the *** to figure out.
 
#29 ·
Service guy just called me and the tech said its the fuel pump. Im a little skeptical at this point but if thats it and they will have be back on the road today then Im pretty happy. The fuel pump is the last thing I would have checked