Ficm troubleshooting! Actual testing info needed

[1997mudslut]

Okay so I have a 05 lly that I have had for around a year. I am very familiar with the injector harness issues and running issues as this is my 3rd lly truck. So for he last 5 months the truck would randomly either shut off or barely runs and sounds like a tractor. Having already experienced this I knew exactly where to look. However the truck had had some motor work done and they installed new pigtails on all 8 injectors and have already rubbed proofed any and everywhere some chaffing could happen.

Now the very first time this happened the edu dude was blown. Replaced it and ran good for weeks. When it happened the second time I went straight to the fuse and it was not blown but by pulling it out and reinstalling the truck would run fine. So as inconvenient that it was I just did that for months. Well I came across a good deal on a lmm so I parked the lly for a month without cranking. I know terrible idea but I've been busy as hell!

So now I'm running through everything tying to get it running again. As soon as it fires it's knocking and if you turn it off only codes are 202 203 205 208 and 2149. If you leave it running after 15 seconds truck shuts off and throws codes 201 202 203 204 205 206 207 208 2149 and 2146.

I have stripped all wiring to find chafes can't find any at all I have ice picked all 8 injectors, dielectric greased everything. I need some actual Info on testing the pigtails and the ficm..

 

[Bonestock]

How are your bale connector connections?

 

[aklbz]

Have access to a FICM you could try plugging in to see if it'll run right?


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[1997mudslut]

The bale connectors look perfect I pulled them out of the ficm did a good inspection tugged on some wires pushed on some and loaded down with dielectric grease. A buddy of mine has a lly I just gotta convince him to let me tear his out and try it lol prolly won't be until Tuesday before I see him again.

Do you guys have any testing I can do?

 

[IOWA LLY]

I don't know how to test the ficm other then trying a known good one on your truck.

But I guarantee that is your issue based on your description.

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[aklbz]

You can test one by just plugging it in real quick and running it for a short time. Don't need fuel lines hooked up to test.


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[036.6turbo]

https://youtu.be/4k-G1dMgFUo

https://youtu.be/Grz_rmClH40

These are long videos and most of what this guy did was over my head, but he did diagnose a FICM on an LLY.

 

[DAVe3283]

You can test one by just plugging it in real quick and running it for a short time. Don't need fuel lines hooked up to test.

Don't need the fuel lines hooked up ever :thumb:

I've been running mine dry (no fuel lines connected) on the valve cover for 2 years & 20k+ miles now. I don't know why they ran fuel through it anyway. The fuel can get just as hot as the air under the hood, if not hotter.

 

[aklbz]

Don't need the fuel lines hooked up ever :thumb:

I've been running mine dry (no fuel lines connected) on the valve cover for 2 years & 20k+ miles now. I don't know why they ran fuel through it anyway. The fuel can get just as hot as the air under the hood, if not hotter.

Yeah it's weird they did that, thought maybe it was for cooling but i don't think it would help much if at all.


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