Signs of injector coking? - Diesel Forum -
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post #1 of 4 (permalink) Old 12-03-2005, 05:26 PM Thread Starter
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Signs of injector coking?

What are signs of injector coking? I've noticed my truck idles fine at first but once warm has a bit of a rough idle. I crank up the 18k mod knobs just a bit and it smooths out while increasing the idle to 750rpm, rather than the stock 650/675rpm.

I do not detect any miss under accelleration. The truck runs great except for a slightly rough idle. I doesn't ever die, just a little rough.

I have yet to run any biodiesel and hope this will clear it up. I'll try some more Power Service.

We haven't had any really cold weather yet... some mornings at freezing but mostly 40's to 60's. Right now its 82 degrees!


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post #2 of 4 (permalink) Old 12-03-2005, 05:29 PM
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Re: Signs of injector coking?

Not sure exactly, but I hope it shows up before messing something up inside the chamber.

Get those EGT's up to 1300......seems like that would help. Not sure, but I try it anyway. [img]/ubbthreads/images/graemlins/smokin.gif[/img]

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post #3 of 4 (permalink) Old 12-03-2005, 07:28 PM
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Re: Signs of injector coking?

If you want to give injectors a good cleaning try a couple of cans of diesel purge, it's a bit more of a pain to use, but does a great job.


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post #4 of 4 (permalink) Old 12-03-2005, 07:51 PM
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Re: Signs of injector coking?

In my experience the only way to make sure of injector coking is to pull the injectors.

On the 6.9 this is pretty straight forward, but on the newer Powerstrokes it would I think be a real hassle.

A very detectable miss in the engine would a sure sign that an injector was either plugged of blocked.

Try the simplest solution first, the liquid cleaning agents for diesels are very good at removing deposits.

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