[hayters]

My truck check engine light has been coming on. When it does it seems to loose power,
and run rough, but then it goes off and goes back to normal. This has happened a few
time in the last few weeks, then yesterday it came on shortly after I started it(not
the 1st start of the day), and took longer to go off. This morning it came on about
20 sec after start, and I turned it off until I could get some ideas what to do. I
don't have a scanner to get the codes. Any help would be great.

Thanks,

 

[hayters]

I Changed the fuel filter, and thought I had solved the problem. I drove it around and
in ran great, although when it first started it was doing the same thing, but after a few
minutes it stopped and ran great. I went out to start it, and it ran fine home, about 9
miles. I started it about 30 minutes lator, and it did it again about 1 mile into the
trip, while starting to accerlerate to highway speed. I then took it to a mechanic that
could scan it. When I got there, I reved up the engine to 2500-3000 RPM's, and it
started running right again. The only code he came up with was P0603 Internal control
module KAM. The tech also checked my batteries, and found one bad, which I took to
Oreily's, and replaced. After leaving Oreily's it did it again, but corrected itself
after reving up the engine. For recap. I have changed the oil, fuel filter, and
battery. Whats the next step.

Thanks,

 

[alexmckinney]

Glow plug wiring harness

It sounds to me that your injector/glowplug wiring harness is shorting out under the valve cover. I have been through this twice. The problem is occurs when the glowplugs need to be replaced. They will sometimes draw too much current when they start to fail and this causes the insulation of the wiring or pins through the valve cover gasket to melt. Once that happens shorts can occur.

I would first start by unplugging the connectors at the valve covers and see if they have melted. If so, you will most likely need to replace the valve cover gasket and harnesses under the valve cover. Might as well replace your glowplugs at that point too since the problem will reoccur later, as it did with me. Might also want to go ahead and replace your injector o-rings while you are in there too.

Also, the connector on the outside wiring harness may have melted. You can get a plug rebuild kit from Ford or International rather than replacing the entire harness. I would recommend getting all the parts from International. I have even found some on eBay since this is a fairly common problem.

 

[Believer45]

CLICK HERE to go to a thread I started when my valve cover gasket plug and under-valve-cover wiring harness fried in Chicago on 4/30/2002. I agree with alexmckinney that this would be a good place to start looking.

If you can get it started and let it run in missing/problem state for a minute or two you can feel the exhaust manifolds - if one feels colder than the other it indicates that side of the engine is not running. Also, with the engine not running remove the oil fill cap and see if you can smell a burned rubber/plastic smell - another indicator of fried wiring harness or plug under the valve covers. Either way, if there is a short the PCM will cut off that entire side of the engine so you will have a 3.65L diesel 4-banger powering a 3.65L air compressor (just kidding).

Dave / Believer45

 

[KnowHim]

I believe its the cam sensor, they are prone to acting up and throwing codes. Worst case the truck will die and not start, most of the time they act up and do like I stated. Good luck.

 

[MilitiaAir]

Ya I would check cam sensor. I always keep a spare just in case anyway. I got the new black one from ford and a expensive blue one from international thats actually for a 466. Glow plugs going bad isnt always the case for UVC harnesses going bad. Sometimes they just go bad. My driver side went bad and all my glow plugs checked out good. My truck will start right up in -50 so I KNO they are good. But replace them if you got the coin. One less thing to worry about. I think they are like 4-8 bucks apiece if I remeber right. It definatly wouldnt be a bad idea to replace the o-rings. I try to do as much preventive work as I can when I start yanking things apart. But atleast check torque to all of the injectors to proper spec while you got the cover off.

 

[hayters]

Is there any way to check this without taking off the valve covers. I already checked the conectors at the valve covers. They don't seem to be melted.

It sounds to me that your injector/glowplug wiring harness is shorting out under the valve cover. I have been through this twice. The problem is occurs when the glowplugs need to be replaced. They will sometimes draw too much current when they start to fail and this causes the insulation of the wiring or pins through the valve cover gasket to melt. Once that happens shorts can occur.

I would first start by unplugging the connectors at the valve covers and see if they have melted. If so, you will most likely need to replace the valve cover gasket and harnesses under the valve cover. Might as well replace your glowplugs at that point too since the problem will reoccur later, as it did with me. Might also want to go ahead and replace your injector o-rings while you are in there too.

Also, the connector on the outside wiring harness may have melted. You can get a plug rebuild kit from Ford or International rather than replacing the entire harness. I would recommend getting all the parts from International. I have even found some on eBay since this is a fairly common problem.

 

[STurbo90]

that doesn't tell you if the wires under the valve cover are melted.

you can take the oil cap off and see if you smell anything burnt.

unless you take it in to get scanned, all anybody can do is guess.

 

[oldrebuiltdodge]

Using an ohm meter check the outside pins between the other pins, and to ground. to ground they should read .02 to 2.0 ohms that will be your glow plugs, between the other pins you should have an open circuit. I should mention that the ohm readings for the glow plugs are with a cold engine. If the plugs are melted on the inside, it's pretty likely that the circuit between the injectors and the glow plugs will show some reading. Use a 20-k scale on your multi-meter

 

[Believer45]

Is there any way to check this without taking off the valve covers. I already checked the conectors at the valve covers. They don't seem to be melted.

As I stated in my first reply in this thread, the smell of burned wiring coming out the oil fill is a strong indicator of shorted harnesses or plugs under the valve cover. Even if it is on the driver side the smell will travel to the passenger side, although not as strong.

As I also stated in my first reply in this thread if you can get it to run when the engine is missing feel the exhaust manifolds to determine which side has shut down.

Also, if you have the truck running and unplug one of the four injector/glow plug external harnesses at a time and listen for a change in the engine that will also tell you, although if the PCM has shut down one bank already you will not be able to tell whether it is the front or rear harness - only if it is left or right bank. If you can determine which side is the culprit I would suggest getting a valve cover gasket and two harnesses and dig into it.

On the passenger side I took the top of the heat shield over the a/c plastic plenum chamber and tucked it down below the head. Then I removed what looks like a vacuum chamber mounted to the engine side of that same assembly to gain access to two of the valve cover bolts, the stuff needing removed on the driver side is obvious. The back bolt on the passenger side is the toughest one to get to, I used a 6" extension 3/8 drive that locks into the socket and a swivel socket (a U-joint stuck into a standard socket is to tall) and lay the extension in the "V" formed where the firewall and the blower motor housing meet, pointed straight down.

Torque on the valve cover bolts is 97 inch-lbs. I did buy a click style inch-pound torque wrench for this job, the bar ones that bend and you read a scale by the handle are nearly impossible to read on most of the bolts that need torqued and unusable on the rest.

Part numbers in case you need them:

Valve Cover Gasket:

Ford - F4TZ*6584*A
International - 1818350C2

Under Valve Cover Harness

Ford - F4TZ*9D930*K
International - 1815923C92

Hope this helps out.

Dave / Believer45