Fixing PO Shenanigans

[dflarsen77]

Fixing PO Shenanigans!

Bought my truck on Saturday, a pretty terrific deal, but it's got problems. I posted about it in a thread before I went to look at it, here (the CL ad is gone):

http://67-72chevytrucks.com/vboard/s....php?p=7636553

So after driving an hour and a half on the way home and stopping to get gas, it would turn over like a champ but wouldn't start. Now, as much as I'm about to complain about PO shenanigans, this ~46 year old truck that I had no previous real knowledge of, still made a 90 minute highway trip with no problems while I was driving. Except it was ~100 degrees outside, which was rough for me

The tow truck guy that towed it home the remaining 30 miles said it smelled like gas in the cab and generally around, and sure enough it smelled like gas. I haven't had a ton of time to look at it, but I've found some stuff that I think could be the problem, but I'm still not sure. A couple notes first. The guy I bought it from said the guy he bought it from replaced the tank somewhat recently. The truck also has 2 auxiliary tanks (either side on the outside of the framerails)

I took some initial pics, posted them in that thread, and I've kind of just poked around and read a ton to figure out what was going on, but I noticed something important yesterday that is probably part of it.

I took this blurry pic thinking it was just the tank switch:


I also took this initial pic of where I know the fuel pump goes. OH YEAH! There's still a mechanical pump:


So yesterday I took a look at that switch more closely, and someone posted the same thing I had, that it isn't just a switch, that's an electric fuel pump. A Facet to be exact once I examined it yesterday. THAT'S RIGHT FOLKS! This thing has both a mechanical and electric fuel pump (btw it's mounted with a tiny c-clamp to the frame and a sip tie to a piece of the tank switch). I mean, if one fails, you should probably have another going just in case. The blurry pic of the facet doesn't show the corrosion around it. It's ground wire is run to the corroded tank switch, so that's probably not great. And maybe the mech fuel pump has the rod out or something. I haven't tried to see if gas is flowing when I turn it over, but I'm not going to bother yet, because these shenanigans definitely need to be replaced! Everything I've read says stick with a mech fuel pump, and I plan to do just that. Anyone want one or two aux fuel tanks?

But wait, there's more!

It still didn't really explain the fuel smell. The facet pump might be dead. There's fuel in the little clear filter right before the carb, and it was working while I was driving at least. So I knew I needed to look around this "new" gas tank to see what was going on. Boy I found some cool stuff. Before I did that, I looked over Bruce88's pretty definitive explanation of EEC on the "It's Just a Pickup" thread page 32:

http://67-72chevytrucks.com/vboard/s...318544&page=32

First, I'm pretty sure this new tank has a non-vented gas cap. Sucked in air that first night when I took it off to fill up, which should mean it's not vented. It has the little holes on it though, which usually is a sign of being vented. I dunno. I assume whatever undoubtedly reputable shop installed it included the gas cap too, and why wouldn't you use a non-vented gas cap on a fuel system with EEC?


My glove box sticker says I have "Emission Control" so I expected to find the high loop vent tube setup. And underneath the cab I see the vent line and fuel line running forward from the cab floor. So I take this pic when I start looking around:


Im thinking, perfect, that's probably it, THE TANK IS DIRECTLY VENTING INTO MY CAB! So i'm look cool, I'll just move the seat forward and look at the sender and stuff:


Oh, that doesn't do anything. And hey what's that?


Oh, it's a giant self tapping sheet metal screw:


And there's one on both sides? Sure, because when you get your seat recovered, and the track stuff doesn't work or maybe it's perished, but you don't want your seat scooting around, so you gotta make it stay somehow. It could be worse.

So I get those out and scoot the seat, eventually decide to pull it. Here's my underseat treasure:


A "The Club", a swiffer, the original glove box (I assume because it's the original color and the one in now is black), a socket, a pen, a utility disconnect notice. Pretty fun!

And I also notice that someone was a Steelers fan:


Anyways, here's what I find. The tank has no vent tube coming out anywhere that I can find. Here's the side where the high loop is:


Here's the sending unit:


At the filler side, the filler isn't vented, which I had expected. And what the heck is that tube hanging down? The high loop thing wraps around the same side, but I have no idea what this is. Any clues?


And the cab floor, you see the vent line and fuel lines:


So from what I've read of EEC, the vent line runs to the front, which I had noticed when looking under the cab, and leads to a charcoal canister by the battery. Sure enough!


You can kinda see where the lines are just cut, and I can see the other side of the cut line just hanging out at the bottom. Anyways, this means that this "new" tank (it actually does look pretty new), installed by an undoubtedly reputable shop, is not a vented tank, but installed into a setup with provisions to be vented, and then they still used a non-vented cap! Well honestly, it could be that the guy I bought it from put that particular cap on there. I'm just trying to express how funny I think the situation is. And also how important it is to fix it.

So the vented set up and charcoal canister really is a good thing, and it's all basically there, although I probably need a new charc canister. Should I replace the tank? Should I find a new sending unit that has a vent line coming out in addition to the fuel line? Is that even a thing?

And I've read more about the Edelbrock 1406, and I had already ordered a rebuild kit with steel pump rod and brass floats to deal with current gas, so I want to keep it, but I'm going to run a pressure regulator. Edelbrock and most guys have noted in forum post that it's best to keep pressure around 5 to 5.5 psi, while the stock mech pump runs at 8+ and the electric pump runs even higher maybe (who knows what they do together, lol). That could actually explain the terrible 6mpg gas mileage on the way home.

But this dude on youtube I was watching did a vid about the 1406 really needing only like 3 psi, showing how much more stable the EGR is, and easier to tune, and how it all goes bananas at 6 psi. So I think I'm going with the summit 1-4 psi fuel pressure regulator and I'll put a gauge on it. I'll replace the fuel PUMPS with a normal stock mech fuel pump (it's a stock engine, and the original block, or at least an original block from that year, has TAX in the serial) which should be all I need. I'll get a new paper type inline filter for after the regulator, and a screen type for before the pump (saw that in a Summit instruction sheet). Someone chime in though if I'm barking up the wrong tree.

I'm basically going to tear out most of the fuel system and replace it with stock stuff, but I'd like to have some opinions on the gas tank issue. And I'm still not positive where the gas smell is coming from. The fact that it isn't vented and the cap is sealed, it must be sucking in atmo somewhere, or when I ran it from 20 to 6 gallons, it would have caved in or something. SOMETHING! But I think once I replace the fuel system issues, the gas smell will be gone, and HOPEFULLY the truck won't be a giant paperweight at my curb. I've been working on all kinds of modern cars for 20 years, had a porsche 914 when I was younger, most recently completely rebuilt a Sportster and painted it:


But here I am stuck with a fuel system issue on a pretty simple fuel system, lol. I wish I had enough time to learn and understand how it works. That's what makes troubleshooting easier.

But man my guy-neighbors have sure taken a liking to it. I've never talked so much with any of my neighbors in the last couple years since I parked this truck in front of my house.