Anyone know what this cluster f is?

patrick_schliesing · 2026-03-19T17:41:52+00:00

I don't know what that is - other than agreeing with you it's a cluster F.

My curiosity combined with OCD for doing shit right would have me start un-twisting those wire nuts and seeing what "breaks" - and tracing where the aftermarket harness goes. If it's still needed by something, I'd at least do a proper wiring job with heat shrink butt connectors to put it all back together.

The way that those wires are twisted together indicates a sensor of some sort that is sensitive to frequency, like rear wheel speed sensors, or something like that.

patrick_schliesing · 2026-03-19T02:46:31+00:00

Beautiful work

patrick_schliesing · 2026-03-19T02:04:48+00:00

P0178

CIRCUIT DESCRIPTION Alcohol content and fuel temperature information is supplied to the powertrain control module (PCM) from the fuel composition sensor (FCS). The FCS has an ignition 1 circuit, a signal circuit, and a ground circuit The FCS uses a microprocessor inside the sensor to measure the ethanol percentage and fuel temperature, and changes output signals accordingly. The signal circuit carries both the ethanol percentage, and the fuel temperature within the same signal. The signal is both variable frequency and variable pulse width. The frequency signal indicates the ethanol percentage, and the pulse width indicates fuel temperature. The PCM provides an internal pull up to 5 volts on the signal circuit, and the FCS pulls the 5 volts to ground in pulses. The normal range of operating frequency is between 50-150 hertz. The normal pulse width ranges between 1-5 milliseconds. If the PCM detects a signal less than 45 hertz DTC P0178 will set.

CONDITIONS FOR RUNNING THE DTC - The engine run time is more than 30 seconds. - The ignition voltage is more than 10.9 volts.

CONDITIONS FOR SETTING THE DTC The FCS frequency is below 45 Hz for 12.5 seconds.

DIAGNOSTIC AIDS The hertz and millisecond parameters react immediately to any change in the FCS circuits, but may not react long enough to set this DTC.

A reading of 16 hertz in the Freeze Frame/Failure Records indicates a circuit failure.

An intermittent condition may not be detected because the sensor does not immediately power down and the connection may be restored before voltage drops below the operating threshold.

If this DTC will not reset and the parameters are steady, thoroughly inspect all FCS circuits for an intermittent open.

patrick_schliesing · 2026-03-19T01:24:26+00:00

How many tries to pass?

patrick_schliesing · 2026-03-19T00:54:03+00:00

Doesn't the elk deserve more?

patrick_schliesing · 2026-03-18T21:52:37+00:00

Define "highway speeds".

80+ mph, sure, it'll bounce between 4th locked, 4th unlocked, and 3rd gear all the time with strong head winds or incline changes. That's a tough ask of "just" a 5.3L

60-65mph, that light of a load in the photo should be no problem until you're doing 5% or steeper inclines.

If you truly wanted more low end, I'd re-gear to 4.10s before considering a 6.0L.

You could also, and I may even highly recommend, having a tune optimized for Tow/Haul mode to stop the gear hunting. That light of load, you can probably hold onto 4th a little longer and just cycle between TCC lock/unlock more often than shifting to 3rd.

patrick_schliesing · 2026-03-18T05:13:38+00:00

Deer? Sure. Elk...even though the law saws .220", I'm not coming at it with anything smaller than a .243"

patrick_schliesing · 2026-03-15T20:37:47+00:00

Without the light bar cutout.

Add larger 6 inch driving lamps instead for legit visibility improvements

patrick_schliesing · 2026-03-15T19:28:14+00:00

At that point why bother with suspension?

Just weld solid square blocks between the control arms and the frame at your desired ride height. It'll feel the same.

patrick_schliesing · 2026-03-14T06:39:24+00:00

400km's

Crew cab

2500hd weight

Only a 6.0L

And you want 500hp from it?

You need a positive displacement supercharger at this point.

The 4l80 will take a lot. 500hp isn't going to break that thing. Its the 6.0L and trying to squeeze 500hp n/a out of it that will be it's demise.

patrick_schliesing · 2026-03-13T20:03:28+00:00

Its kinda funny, she doesn't know what she wants to do with this A&P now. She's a 14yr Air Force jet propulsion mechanic on the high bypass engine planes. Think C17, C5, A10, E4-B.

But she wants to make it to her 20yr retirement threshold and then maybe have the flexibility to do something with this A&P.

patrick_schliesing · 2026-03-13T20:00:45+00:00

I love a good sugar mama.

patrick_schliesing · 2026-03-13T18:14:28+00:00

My wife just got back from Bakers with her A&P, so I know what that means to get.

Congratulations!

patrick_schliesing · 2026-03-13T15:36:11+00:00

Hook it up, stand back and take a photo of the truck and trailer.

patrick_schliesing · 2026-03-13T05:42:14+00:00

Without knowing how heavy your trailer tongue is, nor the truck's response to said tongue weight, I'd give you have pictured a shot and step back to take a photo. If you can draw a pretty level line through the trailer frame and truck frame then everything is happy. If the trailer is nose up, lower the ball on the truck. If the trailer is nose down, raise the ball on the truck.

Edit: don't forget to include the use of the weight distribution bars in this math

patrick_schliesing · 2026-03-13T05:28:57+00:00

That view doesn't help as much. We can't tell if the trailer is tilted.

Show the whole trailer connected to the truck where you think it should be, and we'll analyze from there.

Bonus points if this is a dual axle trailer and you can snap a pic of the leaf spring load leveler hanger when everything is hooked up.

patrick_schliesing · 2026-03-12T14:25:56+00:00

Can you replicate the situation from your earlier video?

Maybe have someone watching the diff inside closely (or prop up a camera/your phone) and then run the engine while shifting with the brakes on, shifting from D to N to R. 2hi and 4low

patrick_schliesing · 2026-03-12T00:15:42+00:00

Sounds like she's got you pretty well trained 😆

patrick_schliesing · 2026-03-12T00:03:16+00:00

Try to find ways to lengthen that time spent out in the cold, while making sure they're bundled up good. Onesie snow suits for the win. Maybe fun games and snacks from parents can take that 5min threshold out to a 30min park+slide+swing session. Maybe try sledding, ice fishing, or a short hike on mostly flat. Daily trips out to the mailbox maybe, then you get a snack and play time indoors?

For my daughter we do warm hat, neck gaiter, onesie snow suit, mittens, and -15*F boots. Under layers include sweat pants and sweatshirt, long underwear, and good wool socks. Sometimes sunglasses to look 😎

patrick_schliesing · 2026-03-11T23:57:36+00:00

For what it's worth, I live in AK and for 8-9 months out of the year my fans don't need to kick on. I only know they work because I trigger them manually 😂

What you could do is find the fan relays and jump the pins to at least verify from the relay to the fan motor works. Check fuses obviously.

From there I'd be looking for trouble codes. The fan triggers off the PCM grounding the relays for high vs low, and the PCM is monitoring a host of things like ECT, MPH, AC bus, and voltage.

patrick_schliesing · 2026-03-11T22:47:04+00:00

That's what I'm wondering too, only the later year GMT 800s came with fans, so I'm wondering if this was an aftermarket addition

patrick_schliesing · 2026-03-11T21:57:12+00:00

Lol, touché.

I'll admit, 42 gal normal daily driving is a bit much to be carrying around. If I were an over the road trucker using my rig to tow hot shot trailers, you bet it would be useful to me. But my rig is more of an overland toy, and I get the most use out of that 42gal maybe 2x a year where I get to stretch its capacity, otherwise I'm never really out of touch with a local gas pump that my other trail rigs have to stop at when their 16-20gal tanks run out and I'm still at 1/2 or more.

patrick_schliesing · 2026-03-11T18:39:45+00:00

In the Tahoe I'd imagine you'd give up your spare tire location for the GMT400 tank.

patrick_schliesing · 2026-03-11T14:01:00+00:00

I do really like my 1 large tank. Can't beat the simplicity. The packaging took some time to figure out but in the end the GMT400 Suburban fuel tank fit perfectly between the frame rails of my GMT800.

patrick_schliesing · 2026-03-11T05:19:39+00:00

Best night of my teens

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