OBS 7.3 runs rough at idle

[08Monster]

I've got a 1995 7.3 that I got in a trade deal, and it runs rough at idle, sounds like it is missing off a cylinder or 2.

Anything besides idle, driving around, the truck runs great and has great power. What causes a lopey idle on these? Like I said, truck makes great power, it has to be up to the 400hp mark. 34psi of boost and still has a haze at WOT.

Relatively new to the 7.3 scene and don't know much about this dinosaurs.

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[DieselDC]

Scan it. If true what you’re describing, it maybe injector / valve cover related.


“Don’t overthink something simple people... ..:sigh:..”

 

[Arisley]

With it being an OBS and not a Superduty, it could also be fuel pressure at idle.

But yes, guessing on these trucks does nothing but cost money. You have to test. A scanner is a must, and a few basic testing tools.

 

[08Monster]

It is an OBS, but it has a superduty fuel system with the 60psi spring in. I have a 55psi and an 80psi spring as well.

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[Arisley]

OK, than that should not be the issue. The PCm does not monitor fuel pressure though, you need a mechanical gauge for that.

 

[08Monster]

I will check tomorrow morning for codes and see what she all has.

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[08Monster]

Here are all the codes. The one with 3 is the KOEO self test codes, the second with 6 is the memory codes.

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[08Monster]

Just a little clip of it while I sat at a stop light.

https://youtu.be/nn3Z3LuVBII

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[DieselDC]

It’s wanting new sensors:cps, icp.

Epbv needs attention. Probably leaking. ****** it. Need new ******d pedestal and a hotside without the valve ($200 total).

Other codes: ignore

Edit: this forum is stupid. It blocked the term “ d e l e t e”


“Don’t overthink something simple people... ..:sigh:..”

 

[08Monster]

It’s wanting new sensors:cps, icp.

Epbv needs attention. Probably leaking. ****** it. Need new ******d pedestal and a hotside without the valve ($200 total).

Other codes: ignore

Edit: this forum is stupid. It blocked the term “ d e l e t e”


“Don’t overthink something simple people... ..:sigh:..”

Think that'll solve all these issues?

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[DieselDC]

Am the other stuff are soft codes and don’t really matter...


No, no guarantee. You need to replace those items then rescan your truck to see if they still exist. Do this to get a base line (I started out with A. “A” being oem parts I changed out that I know function).

That’s the easy route and it’s the route I would take. Prior to doing so, check the wire ends for integrity and ohm them out and check for ground faults. Then if they pass, change them out.


“Don’t overthink something simple people... ..:sigh:..”

 

[gnxtc2]

I would clear the codes and start fresh. Also, change the oil so you know the proper diesel oil was put in.

In the video, what's up with the engine temp light?

Billy T.
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[08Monster]

I would clear the codes and start fresh. Also, change the oil so you know the proper diesel oil was put in.

In the video, what's up with the engine temp light?

Billy T.
[email protected]

The engine temp dummy light and fuel filter light stay on all the time.

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[08Monster]

I forgot to mention, the truck also has very high blowby when warm.

When the truck is cold, blowby is minimal and the truck runs good. As it warms up, blowby increases.

https://youtu.be/erMyLrHmIZI

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[DieselDC]

Forget what I said above. You need a new used engine.


“Don’t overthink something simple people... ..:sigh:..”

 

[08Monster]

Forget what I said above. You need a new used engine.


“Don’t overthink something simple people... ..:sigh:..”

Think it's that bad huh.

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[DieselDC]

10-4. Guaranteed the rings are still in great condition (unless they self destructed). In these motors - rings don’t get worn - it’s them cylinder walls.


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~Don’t overthink something simple~
...:uptight people suck:...

 

[08Monster]

10-4. Guaranteed the rings are still in great condition (unless they self destructed). In these motors - rings don’t get worn - it’s them cylinder walls.


—————signature—————
~Don’t overthink something simple~
...:uptight people suck:...

Well, sounds like a great time to run some heavy ass oil, with some Lucas and stop leak, and sell it. Lol

Anyone know of any remedy's to temporarily patch some blowby?

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[DieselDC]

None.


—————signature—————
~Don’t overthink something simple~
...:uptight people suck:...

 

[79jasper]

Do a compression test. Smoke(oil vapor) out of a RDT means nothing.

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