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.

[dflarsen77]

Oh and speaking of shenanigans, one of the things I was excited about was that it was swapped to front discs, but it still has the original MC and dist block:


So I'll be doing a swap to a disc/drum MC and prop valve. The disc brake setup actually works pretty well. It was making a faint screech like something was dragging when I was first driving, and that could have been the brakes, but it went away after like 5 minutes. I'm not positive it was brakes, but I'll be rebuilding the whole setup. The guy told me he thought the setup came from a 71 camaro, but the castings on calipers tells me it's from a 71 or 72 C10, and the bolt circle is 5x5.

Also found that there was no flexplate dust cover, so I'll be getting one of those:

[In The Ten Ring]

I don't know for sure but I suspect that is an older in cab tank in a 1971 or 1972 model truck.

As for it not starting, vapor lock due to lack of a vent?

[dflarsen77]

Originally Posted by In The Ten Ring

As for it not starting, vapor lock due to lack of a vent?

Yeah man, I assumed vapor lock could be a problem just because it was so hot, and I didn't want to stop, but by my very mathy calculations on the way home, I had used 3/4 of the tank for 3/4 of the trip, and gas would be useful. I thought about leaving it running while I filled up, but you know gas stations aren't a fan of that

And it started up again right when I got home that night. But I've tried the days since then and it just turns over without starting. Maybe if I took the cap off it would work. But then how did it drive all day before then? Either way, all the shenanigans WILL BE DEALT WITH SEVERELY

[In The Ten Ring]

Previous owners.....if they would just make a list of what they did in a book somewhere.... LOL

My truck's PO did that to some extent. My dad was my truck's owner and he has always kept a small book on oil changes, repairs, etc. and I have done the same. When my "soft restoration" is over, I'll take everything down into a book that will stay with the truck.

[GASoline71]

Playing devils advocate here... remember that most people that owned these trucks for the last 40 years basically drove them as work trucks and general transportation. They were into any kind of restoration or "hot rodding". Mainly just shade tree fixes to keep them on the road. If you are buying one of these old rigs and not expecting "PO shenanigans" then you'll be even more surprised the deeper you dig into your truck.



It is what it is...

Gary

[Mrturner1]

LOL this is hilarious and awesome im glad somebody else went through this. I had so much rubber hose and wires to pull out when I got my truck. Matter of fact, two days ago I pulled out a bunch of points ignition wiring harness, some of which was wired to my starter and smoking from resistance. Thing is, it's been converted to HEI for who knows how long. I guess he figured two wiring harnesses has to be better than one lol sorta like fuel pumps I suppose, I mean two is totally safe

[old Chevy guy]

Everything else aside used/ old that looks like the right master and valve for disk drum setup.the valve anyway cause the drum drum setup has the wire coming off the bottom

[tdangle]

looks to me like the gas smell in the cab might be coming from the sending unit assembly. Per the picture you posted, it looks wet. Either is the o-ring seal or the connection is loose and dripping gas.

[dflarsen77]

Originally Posted by GASoline71

Playing devils advocate here... remember that most people that owned these trucks for the last 40 years basically drove them as work trucks and general transportation. They were into any kind of restoration or "hot rodding".

You're right, and I know exactly what you mean Gary. Someday I'm sure someone will look at what I've done to what I think is a stupid complicated cooling system on my WRX and think the same thing. I feel the same way about houses. I complain about POs, but I'm pretty sure someone will complain about my work!

Originally Posted by Mrturner1

LOL this is hilarious and awesome im glad somebody else went through this.

Right? I've posted this kinda stuff in other types of forums, but it's really to get answers about the funny things you find or just the stuff you don't understand!

Originally Posted by old Chevy guy

...that looks like the right master and valve for disk drum setup .the valve anyway cause the drum drum setup has the wire coming off the bottom

Holy smokes you're right! I guess I haven't seen enough pics of a distribution block. Now that I realize that, I see the stock distribution blocks are all square, like blocks, and this looks like the stock prop valves on disc/drum setups! Plus 1! Too bad the booster and the valve are so hideously rusty. It's like rust camo. It seemed like the brakes worked too well to have this part be wrong, so definitely a good thing.

Originally Posted by tdangle

looks to me like the gas smell in the cab might be coming from the sending unit assembly. Per the picture you posted, it looks wet. Either is the o-ring seal or the connection is loose and dripping gas.

Tdangle, I think you're right! It looks totally wet around the whole thing. I looked at it more today, and the sending unit is definitely rustier than the tank. In the absence of any other vent, like the fuel cap, it's going to breath through the next easiest thing, and that should be it.

So now I have to decide how to deal with it. I can replace the tank with a vented unit. I can hope to find one at a junkyard, which seems doubtful to be a reliable solution, or buy the Tanks Inc one at Summit for $150, and a new sending unit for $42. It would give me the vented fuel filler too. I could also reuse the sender (it works), and just get a new lock ring & gasket.

Or I'm looking at a new sender unit at Summit, a Goodmark 4143-755-722 that has a vent tube also. It's for a 71-72 though, so I wouldn't know if it would work. If the hoses are the wrong size (my fuel are 3/8, vents 5/16), I could deal with that, but they should be the same. Someone complained in a review that it didn't work because it's a 30 ohm, and his 72 needs a 90 ohm. But IF it works, I could just run the vent that comes from the sender to the high loop tube.

I'm kind of in a pickle. If I fix the whole EEC thing, I'll also need to get a new charcoal canister. I can get a late model at Pick n Pull for cheap. But ya know, it's money. Should I scrap the plan to do all this wacky EEC venting and just get a vented gas cap? I feel like it will also increase the value, and it's, like, green, and stuff.

Or if anyone is local to the northern CA central valley and has a vented tank, and happens to want to swap. Seems like a longshot though.

[Ken O.]

I started making a list of all the things I was finding just so I could keep track of them all. Some of it was just SO stupid I couldn't believe it. All the major things are fixed, some minor things that I would like to get done soon.