1999 K2500 Suburban

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Picked up this very clean 1999 K2500 Suburban locally. Spent most of its life in Montana/California so the underside is probably the cleanest I've seen for a vehicle this vintage in ND.

Has had a ton of semi recent work done to it. Plugs, wires, alternator, radiator, shocks, etc. Will need a new windshield and there is a front main that appears to be seeping.

Not a fan of the cheap pleather they did for the seats that's off color. But at least they fit nice and the foam seems to have been replaced at the same time. Seat covers will make do for now.

These Michelins are practically new but in ND I consider them basically hockey pucks. Going to replace with new pyo 99-06 wheels in black with 285/75r16 Firestone xts to match my Duramax. It is my new favorite tire since they came out.

 

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Anybody have a set of 2nd row headrests they would let go? Preferably in gray?

 

[imiceman44]

Anybody have a set of 2nd row headrests they would let go? Preferably in gray?

I just got rid of the grey seats a couple of months ago. I held on to them 3 years

 

[imiceman44]

Picked up this very clean 1999 K2500 Suburban locally. Spent most of its life in Montana/California so the underside is probably the cleanest I've seen for a vehicle this vintage in ND.

Has had a ton of semi recent work done to it. Plugs, wires, alternator, radiator, shocks, etc. Will need a new windshield and there is a front main that appears to be seeping.

Not a fan of the cheap pleather they did for the seats that's off color. But at least they fit nice and the foam seems to have been replaced at the same time. Seat covers will make do for now.

These Michelins are practically new but in ND I consider them basically hockey pucks. Going to replace with new pyo 99-06 wheels in black with 285/75r16 Firestone xts to match my Duramax. It is my new favorite tire since they came out.

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I had the same green, tailgate suburban but it was a 1500 with the 5.7
Then I got my black 98 2500 with the 7.4 and barn doors.
It's my favorite vehicle to drive.

 

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I just got rid of the grey seats a couple of months ago. I held on to them 3 years

Never fails!

I had the same green, tailgate suburban but it was a 1500 with the 5.7
Then I got my black 98 2500 with the 7.4 and barn doors.
It's my favorite vehicle to drive.

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Good looking rig!

 

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Finally fixed my paypal account to get premium again. This rig has been getting a lot of fixing lately. Ended up doing an 0411 swap shortly after owning it. This unfortunately uncovered the dreaded P0300 code along with the occasional P0507 high idle that wasn't present with the black box.

After confirming with both Lextech and Black Bear I have learned the 0411 computer in a lot of cases will pick up additional issues the black box would miss due to additional computing power. (Allegedly, but seems to be the case)

The vehicle had headers and titanium spark plug boot protectors that didnt appear to be helping. Had a feeling I would find some burnt plug wires and possibly fouled plugs.

Started with new Dorman exhaust manifolds that I port smoothed a little bit. My dad bought a 96 suburban k2500 that had a tree fall on it which recently had over $14k worth of parts put into it. Including rebuilt L29, transmission, and transfer case (unfortunately an Np243). He needs the 4l80e for his 76.

Robbed the whole exhaust off that one since it was in far better shape than mine. Also did obligatory spark plugs, wires, and complete distributor.

Long story short: misfire still there, so the story continues...

 

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Forgot to mention 5 of the 8 plug wires were burned through. And most of the plugs were black and wet.

Maintenence items:
- Idler
- Tensioner
- Serpentine belt
- Fan clutch

Other fixes I have done chasing P0300, P0172/P0175, and P0507.

- PCV valve/hose/grommet
- cleaned maf
- cleaned iac
- verified tps voltages
- crank relearn procedures after 0411 swap, dist replacement, and crank sensor replacement.

Noticed coolant disappearing from the overflow pretty quickly as our temps have been dropping. Didnt find any external coolant leaks so thinking intake manifold gaskets... Got quoted 900 locally to do it. Decided to do it myself. Also ordered Five O motorsports injectors since I was unsure of what injectors had been put in there by previous owner.

Found upper plenum gaskets completely covered in oil on both sides. Then found all lower intake bolts were wet and installed with no loctite or sealant. Gaskets were wrecked around coolant ports on both ends. So it was a good find as well as finding someone put in BMW injectors before? Searched the number and found they cross to a factory 90s BMW 4.0l of some kind. Possibly why im rich on both banks?

 

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After intake gasket, injectors, fuel pressure regulator, and crank position sensor I don't have the dreaded flashing light of misfire death. No more bank 1 or 2 rich codes and high idle never happens anymore. Runs great but I was still getting misifres on cylinder 4 that didnt make sense. Happened to check the crank retard value after changing the crank position sensor and clearly I missed when restabbing the distributor.

Got the value to -2 and then another crank relearn. No more misfire or codes now. Havent driven it since I replaced all front end components. Alignment appointment tomorrow so hopefully they don't pop up again...

About ready to light the thing on fire or go back to the black box to get rid of these stupid misfires.

 

[imiceman44]

After intake gasket, injectors, fuel pressure regulator, and crank position sensor I don't have the dreaded flashing light of misfire death. No more bank 1 or 2 rich codes and high idle never happens anymore. Runs great but I was still getting misifres on cylinder 4 that didnt make sense. Happened to check the crank retard value after changing the crank position sensor and clearly I missed when restabbing the distributor.

Got the value to -2 and then another crank relearn. No more misfire or codes now. Havent driven it since I replaced all front end components. Alignment appointment tomorrow so hopefully they don't pop up again...

About ready to light the thing on fire or go back to the black box to get rid of these stupid misfires.

I am going to watch this.
I don't have any problems with mine but I was thinking about upgrading to the 0411 and do a better cam.
I am not so sure now

 

[CriticalAction]

I am going to watch this.
I don't have any problems with mine but I was thinking about upgrading to the 0411 and do a better cam.
I am not so sure now

I'll be honest if I were to do it again I would probably just have Black Bear tune the black box and move on with my life.

However, I also cant complain too much about the things I fixed since the intake gaskets were toast, injectors were wrong, plugs/wires bad, etc.

Its just really interesting the black box was "dumber" and didn't care those things weren't perfect. So if you aren't going to fully utilize the additional features of the 0411 is it really worth it?

 

[imiceman44]

I'll be honest if I were to do it again I would probably just have Black Bear tune the black box and move on with my life.

However, I also cant complain too much about the things I fixed since the intake gaskets were toast, injectors were wrong, plugs/wires bad, etc.

Its just really interesting the black box was "dumber" and didn't care those things weren't perfect. So if you aren't going to fully utilize the additional features of the 0411 is it really worth it?

That's my point.
I am fine the way it is, but if I can benefit from a better cam and get more performance then it might be worth it.
I have none of your issues so at least those will not give me trouble.
I do have a leaking fuel regulator which I am replacing soon

 

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Update: misfire still there. Isolated to cylinder 4 and primarily around 2k rpm at 60 mph in 4th gear. Won't misfire if I pull it to 3rd and it sits at 2500 rpm at 60.

Going to try the known good coil and icm from the wrecked 96 to rule that out. Will check plug and wire on that cylinder as well.

 

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After swapping known coil/icm from 86 and doing another crank relearn for good measure I still have misfire in 4th at 60mph/2000 rpm but not enough to throw the light. Not sure what to do now.

Gave it a bath since ND uses too much road salt. And an updated Pic with black PYOs and 285/75r17 Firestone Destination XTs.

Also a local pickup driver drop np241 to solve my "service 4wd light". Current Np246 shifts great to 4low but doesn't like more than 50-100 yards in 4hi or Awd. Pretty sure the viscous coupling is toast. Have a distinct burnt oil smell when trying to drive/actuate awd.

 

[imiceman44]

After swapping known coil/icm from 86 and doing another crank relearn for good measure I still have misfire in 4th at 60mph/2000 rpm but not enough to throw the light. Not sure what to do now.

Gave it a bath since ND uses too much road salt. And an updated Pic with black PYOs and 285/75r17 Firestone Destination XTs.

Also a local pickup driver drop np241 to solve my "service 4wd light". Current Np246 shifts great to 4low but doesn't like more than 50-100 yards in 4hi or Awd. Pretty sure the viscous coupling is toast. Have a distinct burnt oil smell when trying to drive/actuate awd.

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Oh I hate these 246.
I already have 241 waiting for me to put in, and I have the shifter, driveshaft and trim.
I even have the imprint on the hump to cut for the shifter.
I have to unplug the fuse to have 2wd, it will not disengage.
I also got a cable shifter conversion for front axle engagement. It will all go in at the same time

 

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Oh I hate these 246.
I already have 241 waiting for me to put in, and I have the shifter, driveshaft and trim.
I even have the imprint on the hump to cut for the shifter.
I have to unplug the fuse to have 2wd, it will not disengage.
I also got a cable shifter conversion for front axle engagement. It will all go in at the same time

Only thing i don't have is the imprint to cut. Did you scribe that off a factory manual truck?

 

[imiceman44]

Only thing i don't have is the imprint to cut. Did you scribe that off a factory manual truck?

My truck had it.
Look carefully you should find it.
It's not easy to see unless you are a contortionist and know exactly where to look and what to look for.
It took me 3 tries to finally see it, I had parted a truck and knew exactly where and what to look for.
That generation still had some with manual shifter, I saw one recently on Craigslist, it's the base model

 

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My truck had it.
Look carefully you should find it.
It's not easy to see unless you are a contortionist and know exactly where to look and what to look for.
It took me 3 tries to finally see it, I had parted a truck and knew exactly where and what to look for.
That generation still had some with manual shifter, I saw one recently on Craigslist, it's the base model

Just to clarify you are saying that your factory Np246 suburban has the imprint in the tunnel? I just need to contort myself underneath to be able to see it?

 

[imiceman44]

Just to clarify you are saying that your factory Np246 suburban has the imprint in the tunnel? I just need to contort myself underneath to be able to see it?

Yes.
They were stamping all the bodies. It's a very faint imprint but it should be there.
It's on the driver's side of the tunnel

 

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Yes.
They were stamping all the bodies. It's a very faint imprint but it should be there.
It's on the driver's side of the tunnel

Awesome. Would have probably found it when I went to do the swap but good to hear confirmation. Should be doing that swap in a couple weeks.

 

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The "impression" in the floor is kinda half there but not fully. Its enough to get you aligned front to back but depth you have to cut a little at a time if you don't have the template from a manual truck.

I used the backing plate as a guide to how far I should cut and it came out pretty good. The wires/receptacles for the shifter bulbs were actually already there. Just had to put lightbulbs in them.

Interesting enough the 98' Np241 with a 27 spline already had the skinny 6010N bearing in there. The planetary is the same Np246/Np241 so I just put the whole thing in. So if any body needs a spare 241 6 pinion planetary I have one with 27 spline input. 95' and up.

Need to get more pics of the completed bezel but I got the whole stock setup out of a 96' off ebay. Didnt feel like crawling around a u pull at -25 degrees.

Used the front driveshaft out of the wrecked 96' which had an Np243. Ended up using the rear shaft as well since after the swap i noticed the Np241 is 5/8" shorter on the rear than the Np246.

I used Laurence LT Tolmans video on YouTube for guidance on this whole swap. He says you can reuse the 246 rear shaft but I felt a little bit too much up/down play with it splined in for my taste. I had the 243 rear shaft so I measured and sure enough its longer so I put it in.