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Quadrasteer 8.1L Suburban tow rig

2003 Suburban 2500 Quadrasteer camper towing 8.1L 6.0L swap 4L80-E
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That's great to hear!

HP Tuners isn't real user friendly I'm still a novice myself but let me know if you need any help getting set up or working through the tuning.

I highly recommend checking out Goat Rope Garage YouTube channel he explains tuning and HP tuners in easy to understand series of videos.
 
With getting it installed, getting a good read, finding 8.1 file from same OS, doing the segment swap, flashing it in and driving the truck, it would seem like a good first day with HP Tuners. Unfortunately, the next calibration update (to disable MAF and start the VE tuning), resulted in an unresponsive vehicle. Not only would it not crank, I couldn't even use the door locks, much less get the laptop to connect again.

Tonight I built a harness to power up a PCM and connect to it on the workbench (with parts on hand) to prevent any other module on the data bus from screwing things up. This worked and the truck started. So I pulled a bunch of fuses (radio, amp, 4WD...) and tried to flash cals again in the vehicle (at least I was smart enough to park inside this time!) It took multiple attempts but eventually worked (in low speed). Still trying to figure out what the problem is, as pulling the PCM for simple changes is not convenient. They really did put a lot of electronics in this vehicle and I suspect swapping to the touch-screen Nav isn't helping.

VE table seems within 5% from the get-go. I should probably expect that with a stock setup, but you know - Murphy. Did I mention it feels pretty torquey?
 
You aren't touching anything in the truck when you're trying to flash correct? I was told opening a door or putting the window down can fail a flash and potentially brick an ECM.
 
No, all attempts are done with a battery charger attached, headlights off, not touching anything. All kinds of stuff is happening during the write, though. Cluster turns on and off, radio resetting, display telling me to service everything in the vehicle, etc. Hopefully I can figure out a simple combination of fuses to pull to make it more stable. I don't see a lot of problems like this in the HPtuners forum (other than having to pull the radio fuse). If it was widespread across most vehicles there would surely be a lot of outcry. I remember writing 3800s with my DHP/AVT box was uneventful.
 
I know my 14 Silverado and 16 charger will flash and beep all sorts of lights at me when I’m flashing a tune with diablo.
 
Instead of using the stamped steel cover 15000206 that's "correct" for this application, I grabbed the older style 15671932, which eliminates the gap left with the LS style cover 15765623. Haven't decided if I'll make up some kind of torque rods for it.

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It is much harder to get installed, though. I had to remove the front driveshaft, pull the DS O2 sensor, unbolt the exhaust from the manifolds and the exhaust mount that ties to the tranny pan.
 
Well there goes camping season.

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After the windage tray incident, I intended to do another oil change quick. I got it home from work a couple days ago and the oil pressure gauge was down in the single digit area. That's still 1psi for every 100rpm, but concerning. So I dumped the oil last night with about 100 miles on it. This is way too much metal to be some residual debris.

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Is this my fault for running 20 seconds with the oil pump loose? Did metal from the rod bolts/windage tray end up somewhere bad? Was this engine doomed to fail when I dragged it home?

I'm too bummed out right now to make the decision, but feel free to vote on the options:
  1. Tear it down and see what's wrong - maybe it just needs new bearings and minor parts.
  2. Have it reworked at a local machine shop - cost unknown
  3. Grab another used 8.1L for about $1500 and drop it in
  4. Go for a reman like this: https://www.powertrainproducts.net/...MI2JmVjZaO6gIVEPDACh02wATeEAQYAiABEgIG8_D_BwE
  5. Put the 6.0 back in, do some tuning, do some in-state camping this summer and wait for the engine swap mood to strike again someday.
 
Blue85 said:
Well there goes camping season.

View attachment 343336

After the windage tray incident, I intended to do another oil change quick. I got it home from work a couple days ago and the oil pressure gauge was down in the single digit area. That's still 1psi for every 100rpm, but concerning. So I dumped the oil last night with about 100 miles on it. This is way too much metal to be some residual debris.

View attachment 343338
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Ouch! :doah: :yikes::angry1::frown1::ignore::1zhelp:

I would not think 20 seconds would be long enough to single-handedly cause catastrophic permanent loss of oil pressure. I could see windage tray debris blocking the oil pump pickup. And, of course, you'll never know if the engine was junk before you bought it.

Do you think the top end is fine? If this were a known engine, with a known good top end, I'd tear down the lower end and check the bearings. You still have oil pressure, and haven't reported any knocking. You might not have damage to hard parts at this early stage. :dunno:
 
1 then 5

evaluate, then determine the course of action if needed on the 8.1
In the meantime, “simply” plug the 6.0 back in
 
Wait, I forgot a couple:

6. Sell the 6.0 to burn the bridges and fund another BBC
7. Light it all on fire and see how good the insurance is.

At any rate, it seems all roads lead to pulling the engine, so that's the next step. I don't think it's worth dropping the oil pan again to look around.
 
What looks like rust flakes in the oil were really grease or dirt - I squished them up with my fingers. A lot of the debris in the pan is attracted to a magnet.

campfire said:
You still have oil pressure, and haven't reported any knocking. You might not have damage to hard parts at this early stage. :dunno:
Click to expand...

That's my hope...

I really want to see what's going on in there, but it looks like my schedule is going to to be jammed with other activities - such that I'm seriously considering parking the Suburban in the barn until the fall and look at it then. It sucks having the finish line turned into the starting gate, but I'm glad I actually drove it and it was really nice! Passing on the freeway is silly easy - no downshifting - just whoosh. A/C blowing front and rear 70MPH it gave 13.8 MPG round trip. The 6.0 gave around 15MPG, IIRC. Summer plans wrecked, then backup plans wrecked, but If the engine was going to fail, it's better here than towing the family up the West coast.

Of course the next round will be less work than this one was since I have all the bits and pieces that work together now.
 
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Blue85 said:
What looks like rust flakes in the oil were really grease or dirt - I squished them up with my fingers. A lot of the debris in the pan is attracted to a magnet.



That's my hope...

I really want to see what's going on in there, but it looks like my schedule is going to to be jammed with other activities - such that I'm seriously considering parking the Suburban in the barn until the fall and look at it then. It sucks having the finish line turned into the starting gate, but I'm glad I actually drove it and it was really nice! Passing on the freeway is silly easy - no downshifting - just whoosh. A/C blowing front and rear 70MPH it gave 13.8 MPG round trip. The 6.0 gave around 15MPG, IIRC. Summer plans wrecked, then backup plans wrecked, but If the engine was going to fail, it's better here than towing the family up the West coast.

Of course the next round will be less work than this one was since I have all the bits and pieces that work together now.
Click to expand...

Bummer.

Can you just drive one of your other trucks? Or is the big block mandatory?
 
With what we have on the plate right now, we just don't have time to take a real camping trip anyway. If the summer was wide open I'd probably drop the LQ4 back in, before towing on 38's or likely breaking my high miles 1/2-ton.
 
Sucks balls to hear dude. If it wasn't such a pain in the ass I'd drop the pan and pop a couple of main bearing caps and rod caps just for S&G's. See if the bearings actually got munched or not.
 
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