Hello so I refurbished a 6.0 recently, new rings, lapped the valves, new valve stem seals, studs and head gaskets. After resolving a wiring issue, I fired this engine up today and it had noisy valve train sounds, I assumed the lifters had bled down over the past couple of years of that "core" sitting unused. At idle it ran about 10min before that seemed to go away it was still running rough. I had the autoenginuity scanner hooked up and was watching everything as I went along. Noticed on the balance test #4 was over contributing and there was dark smoke coming from the tailpipe. It made sense to me that the black smoke was coming from that cylinder as unburnt fuel. Turning #4 off had zero effect on the engine, it seems totally dead. A couple of light accelerations and suddenly a loud thumping starts coming from the engine, louder at the air filter intake but quite loud overall. I'm at a loss at what happened. I'm going to open it up tomorrow and have a peek. I've read bent push rod but certainly it wasn't when it went in. Anyone have any ideas? I'm also showing a p0105 or something like that which apparently equates to low fuel supply but I have a 1/4 tank showing. I should add that I had to install a pcm that doesn't match the truck today due to the wiring issue, it smoked my old pcm. I'm hoping for the best as I've put a ton of effort and heart into the engine and really don't want to have to pull it again.

Appreciate any help anyone could offer.

Sincerely, Michael

 

There have been several situations where the pushrod gets bent shortly after a rebuild or headwork. Sometimes, the rocker arm breaks.

Some theories are that the pushrod was improperly placed in the lifter. But most times, the pushrod or rocker arm is replaced, and we never have a problem again.

 

HI, so I may not have to tear the entire engine down again, that would be awesome. How hard is it to get the push rod out rocker off without removing the head, what do most people do to achieve this?

BTW,. That comment about the videos I made on my other post was directed at you. They helped me a lot 👍🙂

 

Thanks. Someday, I'll try to recover what was lost when finishing the engine.

You need to pull the injector, set the cylinder away from anything near TDC, and use the OTC valve spring compressing tool. This gives clearance to rotate or remove the rocker arm to replace the pushrod.

Sometimes, they pop up on eBay or Marketplace.

[img alt="
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I've tried three times to post this image...

Here's the link. I think that will show.

https://www.freedomracing.com/rocker...qBoOI4CYcdkXUr

 

I am again very greatful for your reply, it was indeed a bent push rod, despite being really careful to check the bridges and rods, it happened and it had ran for 10 minutes at least before it did. Weird.

I made up the tool, that was pretty easy really, and swapped out the push rod; It runs beautifully now.

On to my next hurdle that I mentioned, I'm showing no tach on the gauge cluster, fuel gauge shows 1/4 tank, all lights, door windows, radio etc work but I'm showing that p115a low fuel code with no comm to the cluster or any other modules. As I mentioned, I had reversed a cab wire when I dropped the cab back on and it definitely took out my pcm. Replacing that and she started right up again but this is my next and hopefully final hurdle. Not sure why it seems like some of the cluster works and some doesn't. Oil pressure, fuel gauge work, odometer works, but no rpm and somehow no fuel level makes it back to the pcm. If you have any pointers on that, let me know. Starting to check the pins later today but everything is hooked up including grounds.

Sincerely, Michael

 

It's cool that you made the tool. I own one, so I have never tried to create one. I'm glad to hear you got it fixed.

It might be a good time to send the cluster to CircuitBoardMedics for testing and possible repair.