5.3 into and 86 4x4 C10

[myzterray]

nothing like stuffing something new into sxomething old! nice truck! how did you get the stock a/c to work?

[Kansas T]

I wired the 86 low pressure switch to the 5.3 wiring harness. The ac compressor clutch output from the factory hvac control head sends power to the pcm ac request wire and the 5.3 ecm is in control of it. I used the hose adapters from Doc's Blocks on the compressor and had custom hoses made to fit them.

[dothedew]

Looks good. Don't mind me asking, which exhaust manifolds did you use?
Any initial start up issues/ongoing issues at all?
Did you do you're own wiring?
Tank question - How did you put pumps in the tank? TBI sending unit, swapped to a different pump?
Can you switch tanks driving down the road? I would think that dead-heading a pump, even for a second or two (such as tank switching) would cause huge pressures and problems....any of that?
Sorry for the questions - midway through an 86 5.3 swap.

[Kansas T]

I used the non egr truck manifolds. I do all my own wiring. I used the original fuel senders and modified them to work with the in tank pumps. Buying the tbi sending units would have been easier, but they weren't in the budget. The aftermarket tank switching valve isn't strong enough to switch while running. It will switch the pressure side, but the return sticks. You end up returning the fuel to the wrong tank and overflowing it. You just have to switch tanks before you start it and there are no issues. The tank switch also controls the fuel pumps, so there is only one running at any given time. Dead heading the pumps for a little bit doesn't hurt anything. I did this swap for a friend of mine and he's been daily driving it since I finished it. One of the walbro pumps failed shortly after he got it, but other than that, no issues. He drives it about 60 miles a day.

[dothedew]

Thanks a lot. No clearence issues on the passenger side with those manifolds? No picture of that side/hard to tell.

When you hooked up you're fuel lines, what did you use? High pressure rubber? Nylon? Stainlesshose? I'm guessing you used the regulator built into the manifold for a dual line setup?

Are you running any sort of VSS?

[Kansas T]

I did notch the frame slightly in the rear by the crossover flange, but I'm not sure I would have had to. I looked through my pictures and I don't have any showing that. I used high pressure rubber hose for the fuel system and Dorman fuel rail adapters to the stock fuel rail and regulator. There is currently no vss and it runs great, but I still plan on putting one in sometime. If you don't use the vss you'll get a high idle code, but it can be shut off in the programming.

[dothedew]

Thanks for all of this. I'm looking to install mine on a test stand to run for a bit to ensure the wiring has all been done correctly, and install during the winter or early spring. Really looking foward to the ability to just turn key and start, rather than pumping the gas and fiddle with the choke

Looking at one of you're pictures, the power steering pump looks like a new pump (5.3 pump). Any troubles adapting the lines to fit the old steering box?

[dothedew]

The aftermarket tank switching valve isn't strong enough to switch while running.

Dead heading the pumps for a little bit doesn't hurt anything. I did this swap for a friend of mine and he's been daily driving it since
I finished it. One of the walbro pumps failed shortly after he got it, but other than that, no issues. He drives it about 60 miles a day.

How long has he been driving the truck since the swap? I've been trying to locate an aftermarket switching valve, and the ones I have found are only rated to 60-65psi or so. If the FPR is located downstream of the switching valve, I would think the valve would see higher pressures than 58psi (pump side of the FPR). Has he had any leaks or anything of the sort? Is his set up this was, or differently?

[Kansas T]

I used the Pollak switching valve that's rated to 65psi. Since the fuel pressure regulator is on the return side of the fuel rail the pressure should never be over 60 anywhere in the system. No leaks in the system, but the drivers side fuel pump came loose the other day. The bracket I made to hang the pump broke free from the sending unit. It was a quick fix to make a new bracket, but next time I'll probably use the tbi style fuel senders.