1979 K20 5.3 Swap

[4WDKC]

Yup, it's OK though. I figure I can do some work with it running (interior stuff) and it's better I do the stuff that is going to prevent it from turning into a rust bucket now, so I can get more enjoyment out of it later down the road.

Do you smell that?

 

[smurfasaur]

Funny you mentioned that, I was watching the new episode of RK garage last night and fell asleep searching craigslist with the limit set to 1800 dollars, lol.

That happens to me pretty much every RK and RK garage lol then my wife catches me on Craigslist looking at more old junk and about has a cow haha


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[4WDKC]

Do you smell that?

Thats the smell of a frame off coming down the pipe you can't see right now.

 

[rpcraft]

Thats the smell of a frame off coming down the pipe you can't see right now.

Seriously, I was already thinking about a way to jack the cab up and roll out the chassis and then how to roll or flip the cab on its side so I can grind and clean the bottom of the truck to install monster liner. I was thinking tough it might be more time sensitive to just put some beams over the joists in the roof of my garage and then lifting it off and putting it on a trailer and having it blasted and lined by someone who does it for a living in order to get a quick turn around.

 

[smurfasaur]

So last night I figured out why the fuel pump wasn’t priming: the random hacked wire from the bulkhead that I tied into to switch the keyed power relay on was too weak to trip the relay. Tied into a different wire and boom I have keyed power.

Also, if anyone is wondering those little retainer clips that hold in the fuel rail crossover tube are pretty important. If you forget to put them back on 60 psi of fuel pressure will blow it right out of the fuel rail. Don’t ask me how I know

Truck still won’t fire. I ran out of time and couldn’t get the damn plug off an injector to check if there’s keyed power there but I’m thinking I have a poor ground somewhere.

I spliced all the grounds together from the harness and grounded them to a single spot of the frame because the spaghetti mess of wires was driving me nuts... does anyone know if that is a problem? I know the factory harness is grounded to a bunch of different places. I do have a ground strap from the header to the frame so the engine itself is grounded as well.


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[rpcraft]

So last night I figured out why the fuel pump wasn’t priming: the random hacked wire from the bulkhead that I tied into to switch the keyed power relay on was too weak to trip the relay. Tied into a different wire and boom I have keyed power.

Also, if anyone is wondering those little retainer clips that hold in the fuel rail crossover tube are pretty important. If you forget to put them back on 60 psi of fuel pressure will blow it right out of the fuel rail. Don’t ask me how I know

Truck still won’t fire. I ran out of time and couldn’t get the damn plug off an injector to check if there’s keyed power there but I’m thinking I have a poor ground somewhere.

I spliced all the grounds together from the harness and grounded them to a single spot of the frame because the spaghetti mess of wires was driving me nuts... does anyone know if that is a problem? I know the factory harness is grounded to a bunch of different places. I do have a ground strap from the header to the frame so the engine itself is grounded as well.


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I'm glad you mentioned that about the fuel clip retainers. I was wondering how important they were.

 

[rpcraft]

So last night I figured out why the fuel pump wasn’t priming: the random hacked wire from the bulkhead that I tied into to switch the keyed power relay on was too weak to trip the relay. Tied into a different wire and boom I have keyed power.

Also, if anyone is wondering those little retainer clips that hold in the fuel rail crossover tube are pretty important. If you forget to put them back on 60 psi of fuel pressure will blow it right out of the fuel rail. Don’t ask me how I know

Truck still won’t fire. I ran out of time and couldn’t get the damn plug off an injector to check if there’s keyed power there but I’m thinking I have a poor ground somewhere.

I spliced all the grounds together from the harness and grounded them to a single spot of the frame because the spaghetti mess of wires was driving me nuts... does anyone know if that is a problem? I know the factory harness is grounded to a bunch of different places. I do have a ground strap from the header to the frame so the engine itself is grounded as well.


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I grounded mine universally to the back of the passenger cylinder and then grounded the engine to the chassis and the frame using a ground strap and then a second connector off the battery ground cable.

 

[smurfasaur]

I grounded mine universally to the back of the passenger cylinder and then grounded the engine to the chassis and the frame using a ground strap and then a second connector off the battery ground cable.

Hmm I wonder if everything just needs to be grounded to the engine... I’ll mess around with it tonight and see what I can find.

A guy at work that has done a few ls swaps was telling me that the two people he’s ever known to do the harness rework themselves have ended up buying a harness due to the headaches from getting everything to work right... I hope it doesn’t come to that.


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[rpcraft]

I went with the concept of the big 3 but I did not ground off the header. Not sure if it really matters but I used one of the bolts like what holds the oil dip stick and used it on the drivers side head and bolted it to the big bolt that is under the brake booster and that is the ground strap. I can take some pictures when I get back home on Saturday but you will probably have it figured out by then.

 

[smurfasaur]

I went with the concept of the big 3 but I did not ground off the header. Not sure if it really matters but I used one of the bolts like what holds the oil dip stick and used it on the drivers side head and bolted it to the big bolt that is under the brake booster and that is the ground strap. I can take some pictures when I get back home on Saturday but you will probably have it figured out by then.

No need for pics I got the concept [emoji1360]

Looks like I’m busy with other things this weekend unfortunately so might not be able to mess around with the truck but thank you for the input. I’m pretty much convinced it’s a ground issue from my research of the interwebs


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[smurfasaur]

Small update: I repositioned my ground strap because I realized that there is obviously a gasket in between the header flange and the head which probably isn’t good for getting a good ground. Also I realized that since I’m not using a neutral safety switch on the 4l60e that I hadn’t grounded blue pin #34 so I believe the pcm thought the tranny was in gear. Still no start

Now I’m highly suspicious of my injectors being clogged because everything else on this motor has been nasty and looks like it’s been sitting out in the rain for ages. Going to take them off and give them a good cleaning (seems like a good idea even if they’re not the issue) and see if that helps. Also have a multimeter arriving today which should help me narrow down any other electrical gremlins


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[rpcraft]

Small update: I repositioned my ground strap because I realized that there is obviously a gasket in between the header flange and the head which probably isn’t good for getting a good ground. Also I realized that since I’m not using a neutral safety switch on the 4l60e that I hadn’t grounded blue pin #34 so I believe the pcm thought the tranny was in gear. Still no start

Now I’m highly suspicious of my injectors being clogged because everything else on this motor has been nasty and looks like it’s been sitting out in the rain for ages. Going to take them off and give them a good cleaning (seems like a good idea even if they’re not the issue) and see if that helps. Also have a multimeter arriving today which should help me narrow down any other electrical gremlins


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Too funny, I had a ground strap on one of the bolts on the coil packs and then i realized the the valve cover bolts are insulated through the rubber grommets and then there are gaskets around the valve cover that insulate as well. One of the things one of the swap mechanics mentioned to me is that when it comes time to fire it up and prime the pump to crack loose the end cap on the fuel rail to clean out the line. he said just wrap it with a bunch of shop rags and flick the ingition on and off for a moment. I figure I am going to do a plus one and put a hidden toggle switch on my FI power line under the hood some place so it will act as both a theft deterrent and a service switch for just the same kind of situation where i want the ignition on but not the fuel pump.

 

[smurfasaur]

Too funny, I had a ground strap on one of the bolts on the coil packs and then i realized the the valve cover bolts are insulated through the rubber grommets and then there are gaskets around the valve cover that insulate as well. One of the things one of the swap mechanics mentioned to me is that when it comes time to fire it up and prime the pump to crack loose the end cap on the fuel rail to clean out the line. he said just wrap it with a bunch of shop rags and flick the ingition on and off for a moment. I figure I am going to do a plus one and put a hidden toggle switch on my FI power line under the hood some place so it will act as both a theft deterrent and a service switch for just the same kind of situation where i want the ignition on but not the fuel pump.

Glad I’m not the only one with brain farts - as my dad would say, with regards to wiring “I know just enough to be really dangerous.”

To be honest I didn’t know you could take the end caps off the fuel rails, but that’s probably a good step to do.

I also like the idea of the extra switch to activate the fuel pump. I’ve known that I want to install something similar since I realized that I’ll have a good chunk of change into my easily stealable old truck once I’m done... I’m thinking of doing a hidden switch inside the cab though so I can use it every time I throw it in park.


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[rpcraft]

Mine has a schrader valve on the crossover tube and that is what they usually refer to i think but it seems like it won't really allow true flow from both sides of the injector rails.

 

[smurfasaur]

Mine has a schrader valve on the crossover tube and that is what they usually refer to i think but it seems like it won't really allow true flow from both sides of the injector rails.

Ahh so that’s what that thing is for?

Small update: injectors removed and soaking in sea foam and carb cleaner, and I picked up a 5ft stock of 3/16 wall 2” square tube and some 2” angle for my crossmember build yesterday, and I have a 3 day weekend. Gonna be a good one hoping to make a poopload of progress


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