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It's always Tuesday- 04 Sierra 2500HD

Eman Resu

Eman Resu

I drink to dat
Joined
May 20, 2020
Member Number
440
Messages
112
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DTW
This is part project blog, part help line for whatever questions arise. No pics yet, will post some eventually.

New to the project inventory is an 04 Sierra 2500HD RCLB 4x4 w/ LS2 and 6" BDS lift. it's dented, rusty, missing seats, needs tires, the brake lines rotted away, rotors and pads are shot, and the exhaust from the cats back is long gone. The LS2 is an 05 GTO long block with the truck's original LQ4 top end, manifolds, and front drive accessories swapped over. I got it in non-running condition and was told the engine could be locked up. I'm undecided on a clear plan for this thing, though am currently working on getting the engine sorted out before firing the parts cannon at it.

I pulled the plugs, removed the drive belt, and was able to spin the engine and accessories by hand. After rigging up a battery the starter solenoid was discovered in-op. I paid $45 for a junkyard starter and was able to start the truck. It idled rough and had good oil pressure according to the stock gauge. What fuel is left in the tank is of unknown age and octane.

First order of business is to get the engine to idle smoothly. I cleaned out the packed K&N filter, replaced the failed MAF sensor, cleaned out the throttle body, installed new GTO-spec AC Delco plugs, new MSD plug wires that came with the truck, and installed a new battery. I verified spark on each cylinder, but the idle is rough. Throttle response is improved, but the idle roughness shakes the truck.

I'm now on the path of vetting the fuel delivery system. According to Googles, the compression ratio of the original LQ4 is 8.4:1 and uses 24# injectors, where the LS2 is 10.9:1 and uses 34# injectors. The injectors in the rail are original to the truck, so 24#. I'm somewhat certain the truck has not been tuned for the engine. Up next is adding a few gallons of 93 octane to the tank and see if any improvements are made, and listening to each injector for a click. A cylinder leakdown and compression test are in the future, too. If significant improvements aren't made, then I'm probably going to swap injectors and phone-a-friend for a tune.

Long wind-up to a Tuesday question. . . What do y'all recommend for an decent but economical set of ~34# injectors, and adapter harnesses if necessary, for the 04 LQ4 fuel rail?
 
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I bought a set of 8 P/N 12613412-8 from lsxeleration for my LS2 I built. Haven't ran my project but they are 50lb/hr stock GM injectors from a flex-fuel application
 
Currently dealing with a few codes: P0141, P0161, and P0300. 141 and 161 were present before I cut-off both cats.. They both were mostly plugged up. Idle and throttle response improved slightly. I added ~4 gallons of 93 to the tank, too.

Currently on the trail of proving out the fuel delivery system.

The injector 1 and 2 fuses are both good.

All injectors measured 12.1-12.3 ohms, so I'm not quite ready to throw a new set of injectors at it yet. I used a mechanics stethoscope and listened for the injectors to click while running. The click was audible and consistent on cylinders 3, 4, 5, and 7. The other cylinders have either a very, very faint click or no click at all. Being a 2500HD model, I'm pretty sure the electronics aren't displacement on demand.

I have a noid light tester on order, so that'll let me know the story on the injectors.

When time allows, I'll hook run a battery of tests (fuel pressure, engine vacuum, cylinder compression, and cylinder leak-down) and determine if this truck is a keeper or parts pig.
 
ridenby said:
Most here can not read or comprehend letters. Take some pictures with that potatoe fhone
Click to expand...
Fair enough.

Here it sits on ~25yr old 305/75R16. Both fronts went flat a few days later. No underhood pics though.
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Not yet, but I will check the fuel rail after the noid light arrives this week.
 
Good news/bad news:

Good = 60psi at the fuel rail

Bad = hole in the block just above the oil pan in the vicinity of cylinder #1.
 
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Here's the half-dollar sized hole in the block at cylinder #1. I'm still considering putting this back together on the cheap. But, that would depend on getting a deal on, at least, a good short block.


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Grab a junkyard 6.0 but swap your heads onto it .
 
It wasn't leaking oil and the front end wasn't covered in oil. It ran like it had a misfire but without knocking or tapping sounds. When I was noid testing the injector harness, I heard an odd knock and that's when I saw the steering box and differential covered in oil.
 
I removed the top end which revealed #1 made contact a few times. The piston was at the top before I pushed it down and snapped the photo. No pic, but the rocker arm stand/rail was broken between 1 and 2. I plan to remove the block tomorrow. I also plan to remove the oil pan and have a look while it's on the stand. Curious to see if the crank is salvagable, otherwise sending it to the scrap yard.

Currently on the path of putting it back together. Haven't committed with buying any major parts or a donor vehicle. . . yet.

Damaged Piston.jpg


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Onward we go. . .

A few weeks ago, I picked up an '06 6.0L w/ steel block, 317 heads. The water pump appeared to be newer and the coolant was fresh and green. At least no rust or oil came out. The expansion bottle and radiator have orange Dexcool, so I'll have to choose a side and flush something thoroughly.

While the engine was out I replaced the oil pickup o-ring, rear main seal, oil pan gasket, and valve cover gaskets. I carried over the better parts from the 1st engine- plugs, wires, most coils, and the throttle body.

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I replaced the front 4 brake lines (MC F & R to ABS block, ABS block to LF & RF). The rear line had been replaced, looked like a PITA to do with the bed on, so just leaving it. Also bought soft lines, pads, and rotors for all corners which will be installed after the truck is running again.

Favorable weather and a free Sunday allowed time to get the engine mostly installed. The gantry doesn't have a fore/aft trolley so pushing/pulling the truck somewhat slowed progress. Next free day will allow getting the nuts, bolts, and connectors of things sorted so I can attempt to fire it up and reveal where I messed up.

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I've had not so great luck with LS engines but I will say that platform does make them quite easy to work on.

Hope you have better luck than I have
 
No real tech, just more blog ramblings about this fine truck.

Since the last update, the nuts and bolts of the engine swap are done. I bought set of '04 manual buckets which included a chrome grill from a 1500. Not really concerned about the 1" HD grill filler piece because don't yet have a plan for the front bumper.

Here is the POS after a quickie car wash before heading to my son's auto shop class for the winter. New battery was dead and old-ass charger couldn't revive it. The class' charger is reviving the battery and hopefully the marketplace motor will fire and be OK.

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Brake lines were replaced a few weeks ago. The class is handling the rotors, pads, and soft lines. Hopefully the calipers are OK. This rear rotor on the other hand. . ..


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Soon after arriving at auto shop, my son discovered someone (innocent whistle) didn't hook up the CPS. He plugged it in and the truck started right away but emphasized a known issue. . . a punctured transmission oil cooler.


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The truck is mostly out of the repair phase and on to preventative maintenance. The oil cooler has been replaced. The coolant system has been flushed and filled. The brake system is complete including flush and fill. The next tasks ahead are:
  • troubleshoot possible parasitic draw
  • transmission fluid & filter service
  • change differential oil
  • replace/repair headlights
  • source and install front bumper
  • source and install center jump seat
  • source and install exhaust system from mainfold back
The truck has open manifolds. Installing bolt-on cats and cat-back system is a ~$1k proposition. The used market is dry because of scrap prices. Building a custom exhaust might not be possible in the class. I have to pick a pill to swallow.

Test driving in the school parking lot is delayed until it gets an exhaust. Auto shop kids appreciated the sound, but not everyone else in the building.

My son asked about lowering the truck because loading dirt bikes and quads will be quite challenging. Not sure I want to open that box of scope creep, but time will tell.
 
The truck was pushed in to the shop and my son drove it out this week. He said the test drive went well- stopped, turned, went forward and backwards without issue or any leaks.

I swallowed a bitter ~$1200 bill for a new exhaust system- both cats to tail pipe. My son picked out the eBay headlights. I was skeptical at first, but like the C/K throwback styling.

Currently on the hunt for a front bumper. Not too concerned about finding the HD grill lower extension at the moment. The PO verified the truck has a 6" BDS lift.

We'll likely get the truck home this week then get after the left bumper mount and bed dents with a porta-power when time, weather, and motivation are in alignment.


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We towed the truck home just before Christmas break and it has sat since then. The weather wasn't too bad today, so I picked at it a bit. The truck had a parasitic draw and weak battery. I bench charged the battery and let it maintain for a couple days. A local guy replaced the instrument cluster stepper motors and backlights, cleaned things up, and repaired broken solder joints.

I installed the battery, added 4gl of fuel, and decided to see what happens. I hadn't driven it or been able to check it out since we dragged it home. It fired up on the first try. I let it warm up while I look things over.

Good: truck fired up, smooth idle, quiet exhaust, no CEL. Wipers, interior lights, blower motor work without issue. Instrument cluster looks good. Heater works great, temp control works, too.
Bad: only tach is reading. OEM radio is "Locked". Two left rear bulbs are out- reverse and turn.

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Decided to drive it around. 2WD, 4H, and 4L work without issue. No odd sounds driving ~15mph. Brakes feel decent, though they haven't been bedded/broken in yet. Not sure what happened, but the engine surged and the instrument cluster came to life. No CEL or other warning lights. Oil pressure gauge rose and fell with RPM.

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Moments later while braking, the truck stalled. It started right away, then stalled as I was turning. It started right away, again, then I drove it to the parking spot. It stalled, then took several minutes before it would run again. A few more cycles of start & stall and I left it in the parking spot. No codes when it stalled, no bucking, jerking, or rough idle, it just seemed to cut out. I didn't have a scan tool, so I'll have to go back and troubleshoot.

Another issue, possibly related, was discovered the night we towed it home. The gas pump would shut off instantly. It took several minutes to put in 5 gallons. I read this could be EVAP related, but I haven't inspected the system yet. The truck had an incident with the shop lift at school so. . .

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More to come with better weather. Until then,. . . a wintery driveway shot.

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Mind adrift, I'm wondering if the stalling issue could be low trans fluid-torque converter. I know some fluid was lost during the engine R&R and more via the punctured line as seen a few pics up. I don't remember buying fluid or my son saying he added fluid at the shop.
 
The instrument cluster rebuild seems to have solved the parasitic draw issue. The truck sat for 2.5 months and started without issue*. It started, stalled, ran like shit. CEL was on- crankshaft position sensor and downstream O2 sensor. I replaced the crank sensor with OEM brand. The O2 sensor wasn't connected, so connected that and all was good.

No CEL lights, woo!

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I let the truck idle for a half hour without issue. I shut it off, let it sit for a half hour or so. I started it again, it had low idle to almost stall before correcting and spiking RPM. No codes though. The serpentine belt squeals, the voltmeter fluctuates a bit during steady idle. The belt tensioner and belt look to be due for replacement, so I'll add that preventative maintenance list.

I'm optimistic that the driveline of things will be sorted out soon. The next decision will be figuring out an end game for it.
 
Replacing the belt and tensioner eliminated the squealing issue. Now the truck is OEM level quiet.

The truck achieved a milestone yesterday- 1st on-the-road test drive. My son and I drove it ~10 miles without issue or drama. The acceleration was responsive, transmission shifted smooth, steering was predictable (though turning radius sucks), and suspension felt car-like. I say car-like because my '07 Ram 5.7 2500 4x4 rides harshly having ~70psi in the E rated tires. The GMC has ~15yr old D rated tires that probably had 35psi. Also it's SFA vs. IFS. The truck didn't shimmy, shake, or wobble at or under 55mph.

Next round of issues to address are:
  • Re-bleed the brakes. The pedal felt spongy
  • repair/replace/bypass EVAP canister
  • replace windshield
  • replace tires
  • deep clean the interior because OCD
  • pick at exterior cosmetics

Edit: Didn't realize that its been a year since dragging this pile home.
 
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I'm not sure which piece you are looking for for the bumper, or if gmc did it the same way as the Chevy that era...I have a 05 2500hd Chevy, that I bought lightly wrecked in the front. I found the steel part of the bumper was the same for 1500 1500hd 2500ld and 2500hd, just used different mounting brackets, and then the plastic top cap was 1.5" or so thicker on an HD truck to take up the gap.

I hated the thick HD plastic piece, so I went to a China aftermarket body shop supply house, bought the steel bumper, the 1500 top cap, and iirc the 1500 brackets

Modified the brackets to lift the bumper up to 1500 height, and pushed forward an inch to make a decent wheel well curve and get it away from big tires no lift:homer:
 
A few weeks ago I picked up a re-pop bumper with brackets, but now lower valance, new un-used from eBay for $120. I slapped it on for first-pass fitment and the driver side sits a bit low. Like Projectjinkie, I'll likely raise the bumper and keep the 1500 grill.


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After damn near a year of waiting for an acceptable used set of tires or wheels to appear, that weren't advertised at 75% retail with 25% tread, I pulled the trigger on a new set of 315/75R16 Cooper Discoverer AT3s on black Friday. The rear brake line was installed just before Thanksgiving. The truck is plated and insured. I'm going to make an effort to get the windshield replaced this week.

Not sure WTF happened, but all of the gauges and odometer stopped working. The backlights, turn signals, CEL works. I cleaned the two grounds on the frame below the driver's door hinge and the wire on the back of the passenger cyl head. The multi-meter read 12V on the cluster connector's pink and orange wires. I verified ground continuity from the connector to the dash structure and steering column mount. I checked all fuses in both fuse panels (engine bay, left side of dash) and all is well. I'm out of ideas other than sending out the cluster to get checked out, well that and getting ahold of wiring schematics.

The truck is throwing a knock sensor code. Add that to the to-do list.


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