Hello all,

This problem pertains to an OBS truck but I never post in the OBS section. First off I would like to say that I have owned 4 7.3 trucks in the past 10 years, currently have 3, this truck being owned the longest. Of the 4 trucks I have NEVER had to pull even a valve cover except one. Only things that have ever needed to be replaced are bolt on parts, the worst being turbos. Outstanding reliability but we all know that.

Had the truck at the back of the property the other day and it choked up and wanted to stall. Killed the key and knew it was the UVCH instantly as I had replaced the same side once before, figured it was a loose connector. Where the truck was parked it was just easier to toss a new UVCH on it and the truck had been running fine. Pulled the plug and one of the glow plug blades burned out. Wanted to get the truck to the barn for other work on it so changed it out real quick (pass. side with harness plugs). Go to fire the truck up and the new UVCH instantly burns out on the pass. side and NOW the driver's rear plug as well. When changing the harness I noticed the glow plug that was suspect was loose inside of the body but was tight in the head.

Question is: Will a totally fried glow plug cause the UVCH connection to burn out? Have always wondered about the glow plugs but the truck has really good batteries and starter so it has no problem starting but is really smokey until it warms up. The truck is a 300k mile Michigan plow truck that was rusted to the grave that I save with a good parts trucks. Everything leaks oil and was neglected for so long. Was planning on just resealing everything because it runs damn good but dont want the same UVCH issue. Also planning on a couple of glow plugs breaking off in the head, just for a worst case scenario.

Thanks

 

A dead short at a GP would do that.

Smoke when cold is not likely related to GP’s. That is typical of tired injectors.

 

Brokestroke, several of us have access to the Ford Service Manual wiring diagrams for the entire truck, including the engine.

Please let us know if you feel a diagram or drawing of a component would help if we uploaded or attached it.

We look forward to a quick fix action.

 

Thanks.

The smoke is eye burning diesel with a hint of burnt oil, blowby is a light puff. Goes away when warm and runs strong without issue.

 

Classic case of bad injectors, you can shim them on the cheap and wive you more life out of them.

As for the UVCH burning change your glow plugs with OEM/Beru only, and the UVCH and harness pig tails.

 

Eye burning smoke due to pissing worn out nozzles.
Just like with bigger nozzles,eyeburning diesel when cold due to the poor atomization.

Shimming might do something as an band aid,helping out oil side to push little more IP to improve atomization.

Do GPs and might as well put big injectors while you are in there..!🤡

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Thanks for the advice guys. Going to tear it down today, fingers crossed on the glow plugs coming out. Good insight with the injectors, I always knew something was up but poor atomization makes perfect sense. Fortunately the injectors only smoke a little. Even with the shape the plugs were in it starts down to 0°f unplugged. Typically smokes for 10 minutes and clears up. Have towed cross country like this a lot. No stumbling, free revving up to 3200rpm is smooth. The truck does have a real subtle rolling lope when it is warmed up.

Voltage drop with glow plugs running is 11.6v

 

I'm thinking that mine drops below 11.6 with the GP's activiated, down into the 10's and up into the 11's when they click off.

 

According to the PC/ED section in the FSM... In addition I have attached the entire pinpoint test (KC) from the FSM for your viewing, if you so choose.

 

FWIW. From what I have read (in the never visited section of FTE ), the OBSers tend to convert over to the SD UVHC as it allegedly is less likely to have electrical issues.

Am not sure if I am going to convert mine as maintenance, or wait until I have an excuse.

 

7 glow plugs came right out, number 8 broke in the head, cant even remove the body from the head.

 

Damn...

There are some hacks for this. Check yourtube.

 

After some prodding around I tried a couple different things until the end cap came off the glow plug. Turns out the body of the glow plug is broken and in the cylinder head. I dont think the tip is siezed though. Explains why the glow plug was loose when I changed the uvch.




They are Delphi plugs...

 

So the problem GP is the one that broke most likely, dam that sucks brother.
Im in the camp of removing the head, its not that hard.

 

Drill and try countersunk tap..??