I have an 02 excursion, with banks power kit (upgraded turbo, wastegate, intercooler, power elbow, 4 in exhaust and chip). I replaced the turbo pedestal, deleted the egpv and aih. Since I had the boost tubes and turbo pulled, and since I had glow plug codes, and since I had around 200k miles I thought it would be a good idea to do glow plugs and injectors. Got injectors and plugs from riffraff and went to it. I used Dorman 1 piece valve cover gaskets. Finished all upgrades and injectors and glow plugs. For about three weeks, I was in love. I was like a teenager driving a hotrod.

then it happened, I was driving down the road and the throttle just shut down. Lost power. I floored it and it revved up very slowly, barely responsive, then hard shifted and drove ok up the the next red light. When I stopped the idle dropped to about 500 rpm and it started shaking. I killed it and restarted and it ran fine the rest of the way home. It did throw a light and I drove it with no problems to an auto part store the next day to check code. They told me icp. So I bought one from them and installed it. Drove it for a day or two with no issues. Then it happened again. This time throwing a code for engine oil temp sensor. Since the symptoms did not match the code, I decided to take it to a shop. They told me I should have all motorcraft sensors and replaced the icp wnd cps with motorcraft (light grey). I got it back and within 24 hours it did the same thing.

Since I clearly have more money than sense, I replaced the ipr. Same problem.

I read every thread I could find on this forum with similar issues. Based on what I read, I checked the injector resistance at the valve cover. All checked out at 3.3 ohms. Checked it from the 42 pin, everything checked out. Backed up to the idm and checked it from there no issues.

So, I got an idm from clay and installed it. Same issue.

Defeated, I checked around and a found a shop that only works on powerstrokes. They told me the buzz test identified a low circuit on injector 2. I told them i had just installed brand new alliant injectors and that i did not think it could be a problem with the injector. They reminded me that they are diesel mechanics who “specialize” in powerstrokes. So I agreed to let them to go ahead and open it up and try a known good injector. I asked them to call me when they got injector 2 and tested a known good injector. I had already discussed it with clay (who assured me that there was nothing wrong with the injector) and I wanted to send the injector back to him if the shop was sure it was a problem with the injector. By then I had read enough on this forum that I had decided it might make sense to have them replace the Valve cover gasket and harness with a motorcraft. But instead of doing what we had agreed, the shop decided to replace the solenoid and put it back together without telling me. But, they assured me it was fixed.

24 hours later, same issue.

so after reading more on this forum, I decided to look at the cps that the first shop had changed. Noticed it was light grey and decided to replace it with one from riffraff. Same issue.

had various random codes popping up, vss, and the other sensor on top of transmission (I forget what one is called)So I replaced both of those. Same issue.

i have wiggled the harness from every angle and checked and rechecked it. I have not once gotten a bad reading on the injectors. The wire insulation seems to be in really good condition.

I started thinking maybe I was having a fuel issue. Checked filter and it was pretty clean, but I replaced it anyway. Same issue.

finally decided to buy ae. I am getting a low circuit on cylinder 2. Cct changes from day to day. Sometimes it passes fine. Other days it might have an issue on 3 and 8.

Most recently, cct said balance fault on 2,4,8.
Last buzz test said 0264 low cylinder two and 1296 multiple faults bank 2. But all injectors buzzed fine. All 8 sounded strong.

When I unplugged the Valve cover gasket to ohm it out again the other day, I noticed some oil in the connector. So I cleaned it out with electrical contact cleaner, blew it out with air to dry, replaced to rubber sealing ring then plugged it back in. All the pins and wires looked fine. Same with the 42 pin and idm plug.

Sometimes whenI start it it goes straight to a rough idle. Twice in the last couple of weeks it has started with the rough idle then died. But it started right back up.

Every time it happens, I can restart and it clears the issue. It doesn’t matter if it is hot or cold (not that it is ever really cold in this part of Texas).

So so I share all that to ask, does it make sense to suspect the valve cover gasket and harness when the injectors all check out with the proper resistance? Or is there something else that I am missing that still needs to be checked?

 

Great job posting your rig's info, the symptoms and troubleshooting you've done, and the AE data.

One idea is to check for chafing of the main harness near the 42 pin connector where it runs across the valve cover. It can wear through and cause increasing symptoms like the ones you are seeing. Here is a link to an FTE thread that might help [LINK]

 

thanks for the reply. i will go back through that harness again. maybe I am just not looking hard enough.

 

I couldn't tell for sure if both of your UVCH have been changed at this point - want to make sure they are connected securely. If they have not been done, replacing both UVC harnesses and valve cover gaskets is good preventative maintenance. The 50 cent mod or the new harness design with improved retention clip will ensure they stay engaged.

 

Yes, I replaced both along with the injectors about 3 months ago. I used the dorman one piece design. That is why i remain suspect of the valve cover gaskets even though continuity to injectors doesn't seem to be an issue.

After replacing the injectors and gaskets it ran like a dream for about 1 month. Then it started doing this.

Also saw this on the link you provided:

"The P0276 indicates the IDM detected that the #6 injector low side circuit is shorted to ground. Check that the underside of the wiring harness going to the 42 pin connector isn't chafed where it crosses over the left valve cover. If that looks good, pull the connector off the left valve cover and check resistance at the second pin from the back to ground, both on the valve cover gasket connector and the wiring harness plug. The resistance should be greater than 10,000 ohms."

I guess trying this on the appropriate pin for cylinder 2 would tell me if it were shorted to ground. If the valve cover gasket pin doesn't read an open, then I guess it would be the problem. And, if the wiring harness doesn't read an open, then I guess i need to look closer at those wires.

Thanks again.

 

This pic shows clearance, but some the wires in your harness at this location may be chafed and shorting to the valve cover. I had this issue with my rig.

 

First off, great job on the description.

second, the Motorcraft or better is a hard lesson but at some point we all have had to learn it. Fwiw.. when it comes to the sensors and electrical Motorcraft is difficult to beat.

As as I was reading your description and trying to trouble shoot the issue I ended up with a possible cause that is fairly rare but when it happens it meets all your circumstance.

where the harness plugs into the valve covers that connectors pins can become faulty, There is a something called a “ Pin Drag “ test that measures the tension of the pins, in my aerospace days we had a handy gauge that measured the clamping force of those pins but if you are very carefull and pay attention you can do it by feel.

take apart an old connection and get a male pin, that bare male pin is your tester.
with the harness out of the vehicle, ( it is actually fairly easy to remove but take pictures of the EXACT routing detailing where and how it is held in place.

On a workbench use your bare male pin to feel the tension of each female pin, if you have weak ones then you need to replace the entire connector with a new Motorcraft pigtail. Always use the Motorcraft pig tails as the cheap Chinese ones have really crappy pins.

next you can strip down the harness to bare wire and inspect for cuts or breaks.
this task is more difficult then it sounds because the material Ford used are designed to meet high heat, vibration and diesel and the readily available consumer products are nowhere near up to the task.

the other difficult part is you need to reassemble the and wrap the harness exactly like it was as there is very little room to route it correctly in the engine bay and wrapping the harness wrong means it will not fit back correctly which almost always results in chaffing and breaking of the harness.

Anyhow, sounds to me like a good chance Your issue is in the harness itself.

I can go dig up the specific info on the high heat and abrasion tape and tubing you will need for the job and edit this post with it.


fwiw... here is a pic of the kinds of breaks I have found deep in the harness that cause your sort of gremlins.
Put sould be noted that these most often are caused when removing the turbo with the harness still in place as it is awakened and heavy and usually gets rested on the harness in the process of taking out of the engine bay.

 

My iPad is being a bitc*$& Trying to upload pics, will post from a computer

 

Since i can not post pics right now here is a quick vid I found showing how to do a manual Pin Drag test without a gauge

 

Probably not relevant, but I sometimes find humor in other people’s misery. So, to the end of entertaining you all I thought I would share. . .

I also replaced the alternator, because it was reading just under 13 volts. I convinced myself that since this feels like an electrical issue, that slightly low voltage may have been throwing off the whole system and messing up the sensors.

I also replaced the ebp sensor and tube. It was throwing a code and I read really deep into some threads that suggested that a fault from this sensor can cause the engine to de-fuel. I thought, “defuel kind of feels like a maybe.”

Of course neither attempt changed my symptoms.

when I watch the injector pressure real time on a graph on ae, it runs steady for about 5 seconds, then drops to zero, the right back up. Kind of like a negative spike, just a quick blip. Is this normal is normal?

also, is the connector that goes into the pcm part of that same harness? I ask because my pcm connector is a bit cracked. The plug looks fine but the plastic shroud that kind of seals it up is cracked. I noticed that when I pulled the pcm to install the chip.

i appreciate all the help. I think I might just replace the valve covers and harness. I wish I had time to go through that harness completely as you suggest. But I just don’t. The cost of a new harness is less intimidating to me than removing, repairing, and reinstalling the old one. I was in electronics repair in the Marine Corps 25 years ago, but I don’t want any part of that chore right now.

What are the symptoms of an improperly installed injector? I keep worrying that I might have not have fully seated one when I installed them. This was my first time. I also lost a copper washer when I installed the injectors. I didn’t see it fall off. But when I looked to make sure it was there before installing, I noticed it was missing and replaced it. But I have worried ever since that it might have fallen into one of the other holes, doubling up the copper washer on another injector.

 

Suspect the Dorman one piece design is flaky on that side. If it were me I would just replace it since everything is molded together and hard to troubleshoot, fairly inexpensive and the problem occurred shortly after replacing. Not knocking Dorman but have heard of this issue over the years on here.

 

For sure the Dorman valve cover connectors are to be avoided but I read it that he replaced them with Motorcraft.

if not do so even if it is not the problem now....or they will be a problem in the future.

 

Since you posted having codes for random sensors all over the truck, check you battery connections and ground at both ends.

 

Have you removed the chip from the equation?

I totally agree on starting with the basics - in-spec system voltage and reliable grounds. As mentioned, the Dorman connections are known to be problemmatic.

 

No. I have not removed the chip. I considered it. But it has been so consistent with idm codes and now with buzz test failures that I talked myself out of it. Also, it ran fine with the chip for a month, I guess I figure that if the chip were part of the problem, it would have started immediately after i installed it.

After reading replies, I believe it is shorted somewhere. I initially was only thinking about continuity of the circuit, I thought that since it ohmed perfect from all three locations that the wiring had to be ok. I did not consider that continuity might read fine even with an intermittent short. I should be able to get on it for a little while tonight. I want to check the injector 2 pins for shorts to ground. I will let y’all know what I find.

in the meantime I have already ordered the new gaskets, harnesses and pigtails from clay.