1991 V3500 Project Heavy Hauler

[68Timber]

The Vortec big block air plenum looks right at home in there, like a factory option. Nice work.

[COS399]

Good tip. Looking great and can't wait to see how it performs.

[MTCK]

Thanks guys. Stock look is what I'm going for. Got a little more done today. Plumbed the Vintage Air condenser and auxiliary transmission cooler. I thought the electric fan from the donor truck was going to work great, and I had a trinary switch to key a relay for it, but there was no way with the dryer being mounted in front of the condenser.

[MTCK]

Also installed new headlights, parking and turn signal bulbs, finished the underwood wiring, installed the radiator, shroud, fan, and rad hoses. The donor truck hose worked for the top, but got a big block lower for a 91' square body.

[MTCK]

Installed the battery trays, batteries and positive cables. Also routed the 110v wires for the heaters for block, oil, and trans pan.

My list is getting shorter, but off the top of my head I need to finish the Vintage Air install, fill the coolant, finish a couple of grounds and the alternator wiring, couple wires to hook up in the cab, fuel pumps and selector valve and I should be making smoke. That kind of sounds like a lot...

[y5mgisi]

Sure is looking good!

[MTCK]

So what are you high PSI efi swappers doing with these factory hard line ends? I was expecting a barb on the tank and hard line with a throw away soft line at the junction. I don't trust these any further than I could throw them. Cut the end off, simple flare and double fuel injection style hose clamps? Thanks for the input.

[DirtyLarry]

I’m having a hard time figuring out the location of your picture as it doesn’t look like how the TBI lines were on my Suburban or Rob’s K5.

In any event, with the L29 having threaded lines at the fuel rail I would recommend building them out of AN adapters and hose. Back in 2007 when I briefly ran a L29/454HO morphodite in the K10 I used all AN bits to connect AN hose to the L29 fuel rail. Unfortunately, I didn’t keep all of the part numbers I used. For the fuel line end at the frame you’ll just have to see what you can cobble together. You should be able to cobble AN fittings to connect to the outlet of existing TBI fuel filter. The return side if you cannot figure out a clean AN adaptation you would be fine to just cut the metal fuel line, slide the hose on and use clamps as the return line has low pressure going through it. If you go that route I would also recommend using some type of cement like Loctite Hi-Tack gasket maker because it dries really hard. That fuel line will never come off once it fully dries!

[MTCK]

Thanks Larry. Sorry for the lack of a description. That is the fuel selector valve down on the passenger side frame rail. I made up braided AN lines to connect from the metric o-ring hard line fittings on the frame to the fuel rail.

The crimped punky looking rubber at the end of the hard lines are all down by the selector valve. Thanks for the tip on the loctite.

[MTCK]

She lives. I'm not going to waste everybody's time with a boring 5 second video of it idling with open manifolds. Lit right off on about 1/4 a revolution of cranking and instantly made 60 psi of oil pressure. No misses, revs crisply and idles smooth. Hope to slide the bed back and get the second pump swapped and get it to the exhaust shop Friday. Oh and the fan in the vintage air system hauls the mail. Moves a ton of air.

[Greenlee]

Congrats Marcus! Nice work. It looks like it came from the factory with that engine.

[MTCK]

Thanks Greenlee! I'm pretty happy at this point. Getting close.

Worked on swapping my drivers side pump tonight. Had to slide the bed back to access the soft lines on top of the tank. Hopefully this weekend I can get everything buttoned up.

[whitels1]

Nice to see this thing getting back on the road, you have done some great work, everything is nice and clean!

[COS399]

Marcus - Do you know what year and model of vehicle that motor came out of? Looks like it came from the factory that way.

[MTCK]

Thanks guys. Donor truck was a 2000 GMC Sierra 3500 (GMT400) crew cab long bed 4x4 with 180xxx miles on it. Ran good and it was tempting to just stab it in but I kind of wanted to rebuild a motor because I never had and it looked like fun.

Got the other fuel pump installed, tank back in, plumbed and bed on. It runs on either tank and I can switch tanks without the motor stumbling. I was kind of curious if that was going to work or not.

[Greenlee]

What did you have to do to get the dual tanks working? I've read on here where other people had problems with the dual tanks when doing this type of swap. Something about the tank selector valve not being able to handle the higher pressure. I'm just curious in case I ever get the balls to do something like this to my truck.

[MTCK]

This switch makes it plug and play up to 65 psi.

http://products.pollakaftermarket.co...mids=1805+1821

Hard to overstate how much fun it was to get the super stiff high psi hoses attached with it in place. Double your patience supplement intake the morning you do that.

Swap of the pumps and valve couldnt have been easier in concept. Take out old pumps put in new pumps. Take out old valve put in new valve. Cut crimped soft lines off existing hard lines. Install all new 250 psi pressure and return soft lines with double fuel injection clamps and high tack gasket cement (not really necessary on the return). Supply line is 3/8, return is 7/16. I'd do it again to have 40 gallons of fuel and no transfer pump.

[MTCK]

Alright here's a fun trouble shooting question. So the first time I turned the key to the run position this morning (to troubleshoot an inop SES light) the fuel pump primed, but instead of turning off after a couple seconds the tone turned lower and it kept running. I wouldn't have thought twice about it but then I started getting a whisp of smoke and hot electrical smell from behind the dash. Shut the key off and now everything is fine and I can't duplicate the problem. Oh and the SES light just needed the tabs bent out a little to contact the printed circuit better.

It did the same thing the first time I turned the key after hooking the battery on the first time, but not to the point of smoking. I fumbled around some and eventually convinced myself that it was just the new smell of the vintage air having air pushed through it. That obviously wasn't the case. I'm going to check grounds around the pcm and fuel pump relay. Anyone had issues with the stock wiring not handling the increased load of these hotter pumps? I'm hoping if I let it sit a while I can duplicate the condition.

[COS399]

Not sure on that one. Good luck tracing it down.

[MTCK]

Thanks COS. Think I figured it out and was a bad ground. One detail I failed to mention was the gauge pinned over at 3:00 when this was happening. Cranked both grounds down a little tighter and will monitor it. And carry a fire extinguisher.

[Greenlee]

You let the smoke out of it. That's how a buddy of mine explains all electrical problems.

Seems like just about every electrical problem I had rebuilding my truck turned out to be a ground. When I first put in the wood bed all of the lights started acting crazy. It turned out the wood interrupted the ground between the bed and frame. When I finally added a couple of ground straps everything started working again, but for a day or two I was stumped.

[wildwilly4x4]

my ep381 burned up the tank selector switch after I went from TBI to the 8.1

[MTCK]

What did you do for the switch, Willy? Assume you had the higher pressure switching valve?

[Grumpus Monkus]

Outstanding job that you have done with the truck!

[MTCK]

Thanks Grumpus. It's the little details that make the difference- vintage air puts dimples in the back of their dash trim strip with vents so you can install the factory trim level badge on it. Can't say enough good stuff about the vintage air system.

I couldn't find a local shop that could fit the 90 degree hose end in their crimper. Vintage will loan you a crimping tool for nothing but the freight. Great service too. They shipped it the same day I called and asked for options. They will also crimp for free if I wanted to send them the hose.