Let's Talk about In-Cab Reproduction Gas Tanks and EEC vs non-EEC

[fishmunger]

OK, spent the last 2 hours reading every thread I could find on replacement in cab gas tanks.

I have a 72 K10 with rust inside the tank. Just had Lars rebuild my stock carb and don't want to clog it all up.

My tank appears to be an original EEC tank, however, there is no sign of the 'canister' anywhere under the hood. Does anyone have a pic of what a complete EEC system should look like?

If my EEC system is not 'complete' should I bother ordering an EEC style tank? I don't need the truck to be perfectly original. Would the older style tank be a direct bolt in as long as I get the correct gas cap?

I've read that I need to get the Canadian-made spectra tank and not the taiwanese one. It appears nobody actually makes a correct 72 EEC tank reproduction with the 1.5" neck, all the repops have the 2" neck anyway. Which is why I began wondering, is it even worth messing with this EEC stuff and I'd be better off just getting the older style tank and calling it a day?

[davischevy]

I just ordered an in cab tank through Autozone. No shipping.

[69Tom]

Interested to see responses here. Haven’t decided whether I want to go in cab on my K10 or not. Keeping it pretty original so I might....

[fishmunger]

davischevy, do you know if yours is a spectra?

[davischevy]

I am not sure. I was impressed with the finish. I did have to change the fuel cap.

The thing about buying through a local parts store, you can send it back if no satisfied.

[davischevy]

I'm pretty sure it is a Spectra, but only pretty sure.

[69Tom]

This thread is 4 years old. so maybe someone started but no one at the time made a correct 72 EEC tank. GMCPaul still doesn't carry one, so I'd assume one isn't made.

http://67-72chevytrucks.com/vboard/s...3&postcount=13

[SRU1436]

Originally Posted by fishmunger

OK, spent the last 2 hours reading every thread I could find on replacement in cab gas tanks.

I have a 72 K10 with rust inside the tank. Just had Lars rebuild my stock carb and don't want to clog it all up.

My tank appears to be an original EEC tank, however, there is no sign of the 'canister' anywhere under the hood. Does anyone have a pic of what a complete EEC system should look like?

If my EEC system is not 'complete' should I bother ordering an EEC style tank? I don't need the truck to be perfectly original. Would the older style tank be a direct bolt in as long as I get the correct gas cap?

I've read that I need to get the Canadian-made spectra tank and not the taiwanese one. It appears nobody actually makes a correct 72 EEC tank reproduction with the 1.5" neck, all the repops have the 2" neck anyway. Which is why I began wondering, is it even worth messing with this EEC stuff and I'd be better off just getting the older style tank and calling it a day?

I have a stock EEC system in my truck, I’ll take a picture of it after work tomorrow and post them.

[OL SKOOL]

Replaced my 70 tank with one from a 72. I might want to go with a ls sometime and this will give me a return line option. Was a Key tank from J.C. Whitney fit is like factory. The first tank was damaged in shipment that shows in the pics. I think it was 160 shipped to the door.

[71gmcC15]

Run all the vent tubes. Like stock then when it comes to the canister just delete it. Add a filter to the end of the main vent hose that runs to the canister and get rid of all the vacuum lines. Never had a problem.

[fishmunger]

69Tom - Yeah, I saw that thread too...and I was like here we go, nothing is ever as simple as it should be!

SRU1436 - That would be super helpful! Mine has an open, uncapped line that terminates underneath inside the frame rail on the passenger side close to the bottom or the radiator/battery box. I had been wondering what it was for. I am guessing it is reminiscent of the old canister.

OL Skool - Your tank looks like it fits like a glove. That's what I'm after. I don't plan on doing an LS swap, so I'm staying traditional.

71GMCC15 - Is that what you did with yours or are you recommending that approach?

It appears that my current tank has the wrong cap on it, and there's no canister. It only has a 2 line fuel pump too. The EEC trucks had a 3 line fuel pump correct? I'd like to just follow the path of least resistance in getting a new tank in here. I don't particularly care if the truck is EEC or not as long as it works right and I don't have to make any custom modifications...

[71gmcC15]

That what was already done to mine. The canister was still there but the bottom was blown out. So I just put a filter on one house that was still there and called it a day.

[69Tom]

Originally Posted by fishmunger

69Tom - Yeah, I saw that thread too...and I was like here we go, nothing is ever as simple as it should be!

No kidding. I'm glad you posted this. I just got a 72 and only had earlier trucks prior to this so I was all set to chuck my original tank and just buy a new one. After reading through numerous threads on the subject, I think I'm going to take my tank to the local radiator shop and have them hot tank it to clean it out and see where I'm at at that point. Mine is a SoCal desert truck, so if it wasn't lacking a cap for god knows how long, there'd probably be nothing too wrong with it.

[fishmunger]

Does yours still have canister?

[davischevy]

Originally Posted by 69Tom

No kidding. I'm glad you posted this. I just got a 72 and only had earlier trucks prior to this so I was all set to chuck my original tank and just buy a new one. After reading through numerous threads on the subject, I think I'm going to take my tank to the local radiator shop and have them hot tank it to clean it out and see where I'm at at that point. Mine is a SoCal desert truck, so if it wasn't lacking a cap for god knows how long, there'd probably be nothing too wrong with it.

I don't blame you for trying to save the original tank. I tried to save the one I just replaced. I put a bunch of time and money into it. All seemed well, then I took it for a drive and started smelling gas fumes. It had developed a pinhole on the back side.

[fishmunger]

Since my system is incomplete and I don't plan on completing it, it's basically going to operate as a pre-'71 in function...I'm thinking I have 2 options.

1) Replace with an EEC tank but it leave it kinda of 'unhooked' and use an old style gas cap.

2) Replace with a non-EEC tank which might be a little cleaner/simpler?

[gpgofast]

Originally Posted by fishmunger

Since my system is incomplete and I don't plan on completing it, it's basically going to operate as a pre-'71 in function...I'm thinking I have 2 options.

1) Replace with an EEC tank but it leave it kinda of 'unhooked' and use an old style gas cap.

2) Replace with a non-EEC tank which might be a little cleaner/simpler?

Gas caps are different between a 1971 and a 1972.

[fishmunger]

Right, but mine has got a cheapo, pre-72 on it already, and gas caps are cheap anyway.

bah someone tell what they would do if they were in my shoes I can't make a decision

[SRU1436]

Here is my canister on my 72 c10. It’s a California truck.

[fishmunger]

Interesting. Thanks sru1436. I bought my truck out of Oregon but don't know if it's whole life was spent there or not. Does your truck have 3 lines coming out of the fuel pump?

[SRU1436]

Yes. The second photo is the three lines coming from inside the cab

[K10-Kansas]

Originally Posted by SRU1436

Yes. The second photo is the three lines coming from inside the cab

I have an EEC tank but I don't have 3 lines in the floor of the cab. I have 2. I have 1 fuel line and 1 vapor line. Does anyone know about these 3 lines?

[ghackett1]

I just put a new tank in my 68 C10. Original truck so it is just a straight tank never had the canister or vent lines.

[RustyPile]

Originally Posted by K10-Kansas

I have an EEC tank but I don't have 3 lines in the floor of the cab. I have 2. I have 1 fuel line and 1 vapor line. Does anyone know about these 3 lines?

I read through this old thread and most of the information is pure bologny and false, erroneous information.. The fuel pump has nothing to do with the EEC system. They are two totally separate systems not connected together in any way..

Starting at the fuel pump, there are 2 variations.. One pump has 2 connections - the rubber line coming from the sending unit in the tank, which is the pump suction line. This line draws fuel out of the tank. The other fitting (a flare type fitting) on the pump is connected to the line that delivers fuel to the carburetor. If you have only one line connection on the sending unit, this is probably the fuel delivery system you have.

The other fuel pump has 3 connections.. Two of the connections work as described above. The 3rd connection is a 1/4" nipple. it serves as a fuel return through a line back to the tank. This recirculation serves to keep fuel moving at a faster rate to help prevent vapor lock. This line runs basically parallel to the suction line all the way back to the tank sending unit.

The EEC system is a fuel vapor only system.. There is a nipple on the gas tank in the upper corner on the passenger side of the tank.. This nipple has a rubber hose connecting to a steel pipe that runs up through the B pillar and back down through the floor in the area where the liquid fuel lines pass through the floor. This line continues along the frame rail to the front and connects to the charcoal cannister located under the battery. Coming off the canister are 2 more vacuum lines connecting to vacuum control pieces on the engine.

The simple facts are:
#1- If you have 3 connections on the fuel pump and 2 on the sending unit, you have fuel recirculation plumbing..

#2- If you have that nipple on the upper passenger side of the tank, you have an EEC system. If the EEC system components are in place and working, you will need a non-vented gas cap for the system to properly function.

[71CHEVYSHORTBED402]

Originally Posted by RustyPile

I read through this old thread and most of the information is pure bologny and false, erroneous information.. The fuel pump has nothing to do with the EEC system. They are two totally separate systems not connected together in any way..

Starting at the fuel pump, there are 2 variations.. One pump has 2 connections - the rubber line coming from the sending unit in the tank, which is the pump suction line. This line draws fuel out of the tank. The other fitting (a flare type fitting) on the pump is connected to the line that delivers fuel to the carburetor. If you have only one line connection on the sending unit, this is probably the fuel delivery system you have.

The other fuel pump has 3 connections.. Two of the connections work as described above. The 3rd connection is a 1/4" nipple. it serves as a fuel return through a line back to the tank. This recirculation serves to keep fuel moving at a faster rate to help prevent vapor lock. This line runs basically parallel to the suction line all the way back to the tank sending unit.

The EEC system is a fuel vapor only system.. There is a nipple on the gas tank in the upper corner on the passenger side of the tank.. This nipple has a rubber hose connecting to a steel pipe that runs up through the B pillar and back down through the floor in the area where the liquid fuel lines pass through the floor. This line continues along the frame rail to the front and connects to the charcoal cannister located under the battery. Coming off the canister are 2 more vacuum lines connecting to vacuum control pieces on the engine.

The simple facts are:
#1- If you have 3 connections on the fuel pump and 2 on the sending unit, you have fuel recirculation plumbing..

#2- If you have that nipple on the upper passenger side of the tank, you have an EEC system. If the EEC system components are in place and working, you will need a non-vented gas cap for the system to properly function.

Good stuff.

If you go by the parts book the recirculated system was installed beginning in 1972ish. I say ish because you know, sometimes they installed new stuff before the next year, sometimes even old stuff from the former year.

You say it has nothing to do with one another, fuel/vapor. Tell that to my former mechanic After the canister and that were pulled he connected the vent line to where a return line would be on the fuel pump replacement. It worked somehow, couldn't tell you, though the replacement cap was vented.

You know what else is BS is vendors sell upper fuel lines varied on whether or not the truck has A/C. It has nothing to do with A/C, some people suggest it does. The difference is whether or not the fuel pump takes a return line. They figure a return line means it's A/C equipped

Here's a tank assembly for an EEC system for reference. Images of the two different fuel pumps too.