My truck has been acting strange for a while now, and then while driving the SES light came on and it began running like an old 2 cylinder tractor. I thought I blew the engine. But after I shut it off and restarted, it ran fine for a couple days then done the same thing again. I ran a scan and came up with the following codes;

P1316-Ignition Diagnostic Monitor Codes Detected
P0267-Injector Circuit Low Cylinder 3
P0470-Exhaust Back Pressure Sensor Circuit Malfunction
P0476-Exhaust Pressure Control Valve Performance
P0284-Cylinder 8 Contribution or Balance Fault

I was told that it was most likely the under valve cover harness had come loose. I was given a test to do to check the UVC harness, and to determine if it was unplugged inside. It was as follows;

Unplug the inboard 9 pin flat connector that plugs into each valve cover gasket.
Test the pins that go into the gasket. The front two pins, and the last two pins are the glow plugs. They should test less than 2 ohms when tested against a ground.
The 3rd, 4th, 6th, and 7th pins are for the injectors, and should test less than 5 ohms when tested against the center, or 5th, pin.

I did this test and found that all the glow plugs tested less than 1 ohm, and the injectors tested 3.3-3.6 ohms.

So, first of all, is this a valid test to determine if the UVC harness is coming off? And if so, does this say the injectors are good, or that the connections to the injectors are intact? Where should I go from here?
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I should add that I have a 2000 F-350 4x4 Lariat PSD Crew Cab Long Bed Truck

 

Welcome to FTE.
Given the track record of the wiring harnesses I can pretty much say that the plugs have come out on the inside, irregardless of what the ohm test reveals.
Just get it over with so you know that it's done, pull the valve covers, retorque the rocker arm pedastals, injectors, and re-seat the plugs. Replace the glow plugs if you want for good measure and take it from there.

 

You might have an issue with your engine wiring harness. Your readings to me indicate the UVC is plugged in ok. When mine came partially unplugged I was reading infinite on two of the glow plugs.

 

How tight should the rocker arm pedastals be? And with the injectors, should I test each solenoid? Should I pull each of them out and look for anything in particular? I hate to be in there and not replace the injectors if they need replacing, but in the same breath, I don't want to replace them if it is not needed.

 

yea dude get ready to pull some valve covers... not a horrible job; just about a days work not sure the foot poundage should be, but if you do a search you'll find it pretty quick. also do the .25 cent mod so you want have to worry about it no more.

 

Since the truck will run fine sometimes, and not run well other times, the ohm test is not 100% accurate. You might have better luck testing when you know the engine is running poorly. Were all the injectors spread across that ohm range, or were most of them at 3.6 and one was at 3.3?

There's no reason to replace or take the injectors out unless you know one is bad. Rocker arm pedestals are torqued to 20 ft-lbs. Injector hold down bolt to 120 in lbs. Then double check where the wiring plugs into the pass thru connector on the valve cover gasket.

 

^^^^^^^^ What he said. ^^^^^^^^^

 

When I tested the pins through the connector, I had just pulled the truck inside and it had been running bad then. And, if I remember correctly, most of the injectors tested 3.6.
What is the .25 cent mod?

 

The loose connectors under the valve cover are a known issue with these trucks. International came out with a set of clips that can be installed to correct this problem. Members here started playing with different types of shims to use instead of buying the clips. It was discovered that a quarter (25 cent piece) happens to be the correct thickness and diameter (if one end is trimmed) to act as a shim. That's where the 25 cent mod comes from. Here's a link that shows what a loose connector looks like, and has pictures of the quarter shim https://www.ford-trucks.com/forums/8...ck-shakes.html

3.6 ohms seems to be typical for the injectors. I have seen an injector ohm out 0.6 - 0.8 less than the others, and that turned out to be a bad injector solenoid that took out the entire bank (truck only ran on 4 cylinders). I'd suggest pulling the valve cover off the side that read 3.3 ohms and taking a look at the harness. If you don't see anything obvious, start the truck with the valve cover off and watch the oil discharge from each of the injectors. If you've got one (or more) injectors spitting out less oil than the others, you may have found your problem. If it's just a solenoid issue, you could swap 2 solenoids that are next to each other and see if the problem follows the solenoid or stays with the injector.

In my opinion, it's worth pulling the valve covers just to torque down the injectors & rockers.

 

Last Friday, I took my passenger side valve cover off 3 times. Once in the morning, the start of heavy traffic on a back road, and the final time on the off ramp right off of I-405. Which happens to be really bad about 5:00. All because of the UVC connector coming undone. Luckily had tools with me. Pull your covers and check them, push on them even if they don't look like they are disconnected. Part# for the clips are 2C3Z14A163AB. If you want to go that route. Thanks to Ed--FTEpartsguy.

 

If your injectors are not spitting out oil, does that mean they are bad? I'm asking because I have my drivers side off and only the first injector is spitting oil, the other three are not, don't know what to do now.

 

The injector will spit oil each time it fires. If they're not spitting any oil, then they're not firing. Check the wiring connections before you start buying any injectors. If you know how to remove and replace an injector, try swapping the 1st injector and the one next to it to see if the problem follows the injector, or stays in the same cylinder (which would indicate a wiring issue).

If you need to know how to change an injector, ask.

 

Would the truck even run if 3 injectors wern't firing? It has a miss and is down on power and fuel econ., but still drives. I tried to ask if anyone has an AE scanner, maybe that would help??

 

Yes the truck will run even if you lose one entire bank (4 cylinders) it's just rough as a paint shaker and won't go very fast.

 

Don't know how to PM, hate to take up space on someone else's question, but not sure what to do.