1999 K2500 Suburban 7.4L

[RedBurb]

Nice job and upgrades. Are you happy with the new LS1 injectors? Curious whether they have same flow rate specs as the original OEMs?

 

[Papablunt]

Nice job and upgrades. Are you happy with the new LS1 injectors? Curious whether they have same flow rate specs as the original OEMs?

I'm happy with them. They dropped in without issue or modifications, but they're quite a bit larger flow than OEM injectors and will require a tune, or it will run rich and set off a CEL.

 

[Papablunt]

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Just a few quick progress updates...

While cleaning out the garage, I found a pair of front door weatherstripping I bought a couple years back. My helper (Zoey) and I were able to knock out both doors in about an hour. Now the doors close solid and firm, and the "whistling" sound is gone.

Also buttoned up the front end and threw the hood back on. Feels nice to have it 100% back together.

I finally got a baselog sent off to Blackbear. Thankfully, I didn't need an initial tune to get it running. I was slightly concerned the new injectors might be too much without tuning, and I wouldn't be able to collect a baselog. Looking forward to the tune arriving soon.

 

[Papablunt]

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Well, lookee what we have here... she's finally tuned.

Blackbear did a great job on the tune, as usual. Pre-tune... I was surprised that it even ran as well as it did with the bigger injectors + cam, but now it's a whole new animal. There is a considerable amount of low-end torque now. I'm happy that I chose a cam that focuses power on the lower RPMs. Coupled with better transmission tuning, I can give it plenty of juice and it just stays in gear and pulls. I haven't really had a chance to get out and drive for more than half an hour, but hopefully soon I'll at least be able to go through the 2+ year old fuel!

The tuning certainly dialed in a lot of the hiccups, but I'll be sure to send in a follow-up datalog to really get it dialed in. I'm showing a couple misfires pretty much across the board when she's cold, but it goes away when warm. I've read somewhere that these 454s really prefer 0.045 gap over the 0.060 OEM gap, so I'll try that and see what happens. I'm also seeing an EGR code (P0401) for insufficient flow, but that should be an easy fix. I forgot how bad the exhaust manifold leak is. I'm going to get that taken care of sometime in the summer, but she's been under the knife for a couple years, so she deserves to be driven.

 

[1952Chevy]

Nice looking rig! I bought mine with a rod knock, and threw in a motor from a parts truck I bought. I freshened it up, but didn't add any performance upgrades. Maybe in the future. Look like you got a pretty clean truck!

 

[Supercharged111]

I had a P0401 in my flipper dually, a junkyard EGR valve was the fix there. All the plumbing was free and clear and watch out because the small block valves are a different size.

 

[Silverado1994]

I bought this Suburban from my Dad a couple years back (Nov '19), and I'm finally getting around to showing it some love.

My pops lives in NC and I'm in CO, so we met 'half-way' in Omaha, NE to exchange. It was a wild ride heading back home between the heavy winds and sloppy rag joint, but it pulled just fine.

He pulled his XJ behind so he could get back home:

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And I pulled our Accord back home:

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The tires that were on the 'Burb were pretty horrible. The well worn MTs were incredibly loud, and you could feel each lug under 20mph.
While the OEM wheels are cool, I immediately dropped those in favor of some PYOs. I am a big fan of Wildpeak AT3W tires... these are 265/75-16s:

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Shortly after, I installed 2" Stahl steel spacers at the rear:

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Good looking truck. Those tires are pretty decent. I work in a fleet shop and I just made the swap to these from the Firestone AT2 tires (which are flimsy / horrible tires) to Falkens. For a heavier and definitely stronger tire they sure balance out well and with not a whole lot of weight.

 

[Papablunt]

I had a P0401 in my flipper dually, a junkyard EGR valve was the fix there. All the plumbing was free and clear and watch out because the small block valves are a different size.

What's interesting is this is a brand new Delphi EGR. I wasn't having EGR problems before, but figured a 20+ year old EGR might be due for replacement. After driving a bit longer, I'm now seeing a P0401 and P0405 EGR code, taking about 10 miles for the codes to produce. Watching the EGR voltage and duty, it seems that the EGR likes to work sometimes, other times not. Need to get the multimeter out and do some testing... but I'm certainly not opposed to an EGR delete if this keeps giving me hell.

Good looking truck. Those tires are pretty decent. I work in a fleet shop and I just made the swap to these from the Firestone AT2 tires (which are flimsy / horrible tires) to Falkens. For a heavier and definitely stronger tire they sure balance out well and with not a whole lot of weight.

I've had these Falken AT3Ws on three different vehicles and they're one of the best tires for my purposes. They are quiet, and wear pretty damn well too... I saw 50k out of a set with lots of offroading. Unfortunately, the word seemed to have gotten out a couple years back, and the prices skyrocketed. I just replaced a set of Falkens with the Goodyear Ultraterrains, and they're pretty comparable to the Falkens so far. Time will tell how they wear.

 

[HotWheelsBurban]

Very nice Burb you have there! PY0's look so cool on these trucks.

 

[Papablunt]

Fixed my idle issue and EGR CEL. Found a vacuum / exhaust leak at the EGR. The EGR was tight, but not tight enough to fully seal. Went to tighten the bolts, and I ended up stripping them. That aluminum is sure soft. Fixed the threads with a helicoil and all is good now.

Still trying to go through the 2 year old fuel. The tires have noticeably smoothed out

Short list:
- Steering rebuild
- Fix broken exhaust manifold studs
- Gibson shorty headers
- 3" custom exhaust into Walker school bus muffler
- Re-tune

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