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79' GMC C15 - Spruce Caboose

79 GMC 1500
Well I’ve been working out of town but managing to get some cruises in the truck so far on days off. I’d say I’ve probably put about a few hundred km on it so far without any issues yet.


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I managed to fab up a mount on the door side for my sons child seat, and used the middle belt male end doubled up on the inside so the regular belt has the female end and the car seat can buckle into the male end.


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Right on Nick!
 
Couple things that I learned recently ..

The air pressure at the back half of the intake is quite more than the map at the front of the manifold, so if your using the built in map sensor in the term x it matters. I’ve had two map sensors not read right with the holly system. Stock one which could have been bad since the junkyard and then one I bought ( which wasn’t gm but not Chineseum either) I didn’t mess around with trying to scale it by voltage in the Holley ecu and just went to the inboard one. I had two available ports on the gen 4 intake, one on the back half and one near the TB. The one at the back half I was using was fine until throttle applications where it would spike up and run out of fuel table to quickly and over fuel.

Running my injectors at 43.5 psi is much smoother and easier to tune than at 60 psi. They are 52lb /hour injectors which ended up being overkill but gives me space for upgrades.

Even if your transmission dipstick has two o rings, just fuggin rtv it anyway…

A loud truck isn’t always a fun truck. This borla muffler needs to go.

If you take a rear leaf out of both sides. Leave the one on your fuel tank side in…

6.0Ls are neat



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Building a 6.0L now?



…I guess I have to now haha. A good buddy of mine is moving back to AUS and dropped off a bunch of LS stuff he had laying around the shop and one thing was this shortblock. It was gifted to him so he’s got no real info on it but it was never detonated to bits so should be a good core. It’s an LQ4 I think by the casting number. I don’t really need to spend a bunch of money on a new motor and I don’t want any more projects as I have way too many on the go, but I do think it’s a perfect building block to learn about assembling/disassembling the bottom end of these things which I haven’t done yet.

I’ll toss it on the stand and it can be a long term project that I throw money at when I can over the years. I’d love to get it hot tanked and decked if needed at an engine shop, and start fresh for a long term build.
 
I managed to fab up a mount on the door side for my sons child seat, and used the middle belt male end doubled up on the inside so the regular belt has the female end and the car seat can buckle into the male end.

Aren't you worried the airbag is going to hit him in the back of the head? :rotfl:

On a more serious note, looks like he is growing fast!
 
  • Haha
Reactions: bix
The air pressure at the back half of the intake is quite more than the map at the front of the manifold, so if your using the built in map sensor in the term x it matters. I’ve had two map sensors not read right with the holly system. Stock one which could have been bad since the junkyard and then one I bought ( which wasn’t gm but not Chineseum either) I didn’t mess around with trying to scale it by voltage in the Holley ecu and just went to the inboard one. I had two available ports on the gen 4 intake, one on the back half and one near the TB. The one at the back half I was using was fine until throttle applications where it would spike up and run out of fuel table to quickly and over fuel.

Something sounds a little off there. How is it running out of fuel table? It can only go up to atmospheric pressure or down to true vacuum, both of which should be on your table, unless you have some super race tuned induction system that has higher than 100% VE, which is unlikely.

If the same sensor was hooked up to the main port on the intake, it should be reading the same. Be careful where you hook it that you aren't hooking it to ported vacuum or some port that isn't in the main body of the intake manifold, sometimes they are connected to runners that go elsewhere.

How long is your vacuum hose to the internal MAP sensor? If done correctly they should read the same as external, its just there may be a small delay on the internal since the pressure change has to travel through the vacuum hose.
 
Something sounds a little off there. How is it running out of fuel table? It can only go up to atmospheric pressure or down to true vacuum, both of which should be on your table, unless you have some super race tuned induction system that has higher than 100% VE, which is unlikely.

If the same sensor was hooked up to the main port on the intake, it should be reading the same. Be careful where you hook it that you aren't hooking it to ported vacuum or some port that isn't in the main body of the intake manifold, sometimes they are connected to runners that go elsewhere.

How long is your vacuum hose to the internal MAP sensor? If done correctly they should read the same as external, its just there may be a small delay on the internal since the pressure change has to travel through the vacuum hose.

What you’re saying makes perfect sense and I should re word my mouth vomit. It wasn’t running out of fuel table but it was reading very high MAP at 2500 rpm beyond which seemed to make it miss its whole middle range progression of the fuel table. It was also reading 5+ kpa higher at idle in the old location. The new location is much closer to where the stock map sensor is located which I’m sure gm has in the proper area of the manifold.

As for the sensors, I heard the Holley really only likes genuine map sensors and I assumed that’s what the issue was with my off brand unit. I should have gone into the software and looked at the voltages it was getting from 0-5v ( I believe it’s a 5v sensor ) or tried to get some info to plug into the custom map sensor table on the Holley , but going to the internal just seemed like less room for error and more trustworthy.

The plugs kept looking over fueled so between changing the internal map sensor location and dialing down the fuel pressure I think I solved that issue.

That’s a great point about where those male ends on the manifold go which I never considered and my Holley is mounted right on the inside of the firewall so I believe the tubing is about 3 ft long.

Aren't you worried the airbag is going to hit him in the back of the head? :rotfl:

On a more serious note, looks like he is growing fast!
I’m sure all the millennial and gen z moms at daycare are when I roll up to get him in this thing … :flipoff7:
 
I’m sure all the millennial and gen z moms at daycare are when I roll up to get him in this thing … :flipoff7:
The first time I put my son and his car seat in my square body momma bear was not happy but he had the absolute best time hearing the noises and watching me shift. I mean ya these aren't the safest vehicles but he's in a harness in a car seat. They still sell regular cab trucks today which is only a problem if you don't turn off the passenger airbag. Good thing square bodies don't have air bags so no need to worry. ;)
 
Well the transmission survived its first 190km highway trip to pick up this canopy I found in a field, with lots of 3-4 shifting on the hills and flat spots on the road. Transmission temp rose to about 220-230 and then cooled down to an average 200-210 for the the 90 some km each way. Gotta say … I’m pretty stoked it hasn’t imploded yet and should pull the trailer without getting too hot.

I was really hoping to make a camping trip with Rene this August but it turns out work will be screwing me on that one, but I do still want to put some airbags in the rear for leveling out the camper trailer, and I still need to find a hitch for the rear.

I’ve also come to the realization that having this kid means the bench seat needs to go back in, or maybe a newer 60/40 sort of set up, but something the whole family can pack into. This canopy will be great for rain protection in spring and fall and shouldn’t need too much of a tidy. The square stock that was used for the rack will need some replacing and new hinges for the rear door , but other then that it’s pretty solid.

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A month or so ago I had also rearranged a lot of the wiring for the truck, the Holley ecu being mounted on the passenger side left lots of wires running the entirety of the cab and into the stock fuse panel. I ran a 100 amp relay with a 12v trigger from a keyed on stock location, and installed a separate fused distribution block right beside the terminator for all the accessories and terminator x connections. It’s nice to have only one frame ground for those and a lot less wiring. Still a bit of a mess but it’s a lot better for now at least

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Gonna miss seeing you guys when we're out there in a few weeks. Woulda been cool, we're bringing both daughters and our Grand Daughter Hailee. Wyatt and her would have had a lot of fun...

Canopy look decent! The car seat thing get easier once it's forward facing.
 
No news is good news I guess! Working in town again and daily driving the truck to work right now ( which is about 120 km a day). I’ve probably put 1500 km on the transmission so far and the truck without any major issues. Trans temp is usually around 180 F and rarely sees 200. Theres still lots to do but getting these cold starts every morning figured out and highway cruises to work is a good test. I was thinking it may be a good thing to drop the transmission pan and change the filter after a fresh set of bushings and internals have had some miles put on them?

It’s not by choice that I’m daily driving the truck going into winter but hopefully I’ll have the dad-mobile fixed in a couple months and working on the c10 again more consistently. Wyatt has proven himself by loving the truck and not minding the exhaust rumble and even slept for an hour drive today on the way back from a buddies. I was a bit worried about if the exhaust drone at certain rpm’s would bother him or not. I bought him full ear muffs but is only starting to like things stuck on his head so it’s nice to not fight that battle for truck rides. The borla exhaust was brutally loud , so I did switch it out with thrush hush muffler which I enjoy the sound of way more and I also got rid of the over the axle portion and just dumped it downward at the rear axle.

I have noticed a slight ( but annoying )vibrations at certain speeds 50 mph and up, so I’m going to take a look at my driveline angles again and see if anything has settled or changed. It’s so nice driving this truck with modern transmission and engine, never struggles and just powers through the up and down highways and cruises 60 mph at about 1800 rpm. Such a change from the old worn out 350 quadrabog..

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Wyatt is getting big, and still looks as happy as can be! Both my girls never seemed to mind the Flowmasters on my old Jimmy, to be honest if they were cranky we used to just load em up in the K5 and go for a drive...they never lasted more than 5 or 10 minutes before they were out like a light.

There isn't anything better for working the bugs out of something than to have to drive it every day. :waytogo:
 
Wyatt is getting big, and still looks as happy as can be! Both my girls never seemed to mind the Flowmasters on my old Jimmy, to be honest if they were cranky we used to just load em up in the K5 and go for a drive...they never lasted more than 5 or 10 minutes before they were out like a light.

There isn't anything better for working the bugs out of something than to have to drive it every day. :waytogo:

Yea he’s filled with piss and vinegar with lots of smiles on top and I can totally see them passed out in the back of the k5. Those 37s and Alcan springs probably helped rock them to sleep!

yea things like dome lights that work have never brought me such joy, I also installed a stereo behind the seat so something other than AM radio has also been pretty crucial.
 
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Well dang… life with a toddler sure is different… I’ve made some changes so I can be home more and actually enjoy my life and the things I’ve worked so hard for. Sure the thought of debt is crippling … and the idea of a new career is horrifying and exciting, but I’m getting time to wrench on the truck again which is rad! I’ve decided to start working for myself , doing handy man services in my local rural area. The smallest property out here is 2+ acres and we are quite removed from the closest towns and there seems to be a real need for local industry as more people run away to the woods to escape the current socio-economical situation…..

All in all that’s maybe another topic to post about, but who doesn’t love a good derailing of a thread!?

To sum it up , the truck will now have to perform, be comfy and reliable. It’s not far off but like any build…. So many little things to button up or change that just never got done prior or after. He insurance expires on my car come may 11th , so I have my work cut out for me considering I’m currently a stay at home mom for the time being.

The list has so far is:

Check on rear diff
Get rid of vibration at 55 mph+
Rear brake caliper swap to CPP calipers I’ve had on a shelf for years because of 7/16 banjo bolts
Install hitch receiver
Move rear brake lines for bump stops/possible air bag installation ( mainly for hauling our camper )
Trans fluid and filter change ( aprx 4000 km since rebuild )
Remove bucket seats and console
Re install bench seat
Working speedometer / tach / fuel gauge
Build out dash cluster with functioning gauges
Shifter stick ( 3/8 ratchet extension is getting annoying )
Remove toolbox and battery in bed & relocate battery to engine bay
Install air oil seperator
Install 87-91 washer pump reservoir and pump into existing wiring
New wiper switch
New headlight switch
 
Some photos so far of the progress.





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I had these rear caliper mounts in bare steel sitting outside on the truck and they got crusty fast, so I gave em some paint!
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Didn’t think much about where these lines sat when I made this rear brake setup using the stock front calipers and lines… one massive bump with the trailer and I’d probably take out my rear brakes. This is also the area the air bags will sit in if I get some for leveling purposes with the camper. I ordered some 7/16 banjo lines so I’ll relocate the hardlines away from this area.
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Got the accelerator pedal bracket made. Nothing too fancy but tacked up and ready to be welded now.


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I also found this under the hood light in my rubber totes of junk, and is a nice memory of my k5 as I quite liked this little light. Wonder if I can put an LED in there for better brightness.

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I got the brakes disassembled in the rear and got the new 7/16 stainless lines on the calipers. Going to relocate the locking bracket to the backside of the axle tubing to allow bump stoppage.

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I guess the battery is going on the drivers side because that’s the side I have a tray for.


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Also humped the ol shop seat back into the truck. I plan on reupholstering this one day and putting heated seat warmers in it but I can’t quite stomach the cost at the moment until someone buys my bucket seats and centre console.


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