california laws about adding a fuel tank

[mrnda]

have a truck that i want to add a second fuel tank to but am unsure about restrictions in california.  Has any one from california done this before, i know that for smog inspection reasons there is a vacume leak check but if there are dual tanks they can not perform this.  I believe there are permissible upgrades or modification to your vehicle that can be made but am unsure about adding a second fuel tank.

Thanks for any input or shared lessons learned.

[mach1mustang351]

I know if it has dual tanks they cant run the evap test.  As far as I know they won't be able to trace if it was a factory dual tank truck or not.  That is vehicle option and that info is not on the emissions sticker.  I think you would be okay and they can bypass the test.   

[mrnda]

Thanks for the info.  i will give it a go, one saddle tank with an early eighties engine equals alot of stops at the gas station. 

[mach1mustang351]

Just make your addition look legit and I don't see you having a problem.  I added a second tank to my '73 and it is super easy to do... it kind of surprised me.  I was in good with one of the wrecking yards and they told me they don't have to drill the tanks until they crush the vehicle so I would check there.  I got the tank and the sender for $40.  I miss those junk yards... AK junk costs too much.

[mrnda]

Thanks for the info, i have a doner truck my brother gave me with both tanks.  all of  the hardware works and both tanks pump so i will not have to pay for the bed, tanks, or controls, but i may replace all of the fuel lines while i am changing the bed.  Looking forward to the project. 

I do have a question about the fuel gauge though.  at what point does the fuel gauge switch sending units from one take to the other?  where do those wires tie in at and how will i have to change the circuit board behind the bezels for this to work correctly?

[Captkaos]

The tank selector switch determines which tank is displayed.

[VileZambonie]

there is a vacume leak check but if there are dual tanks they can not perform this

What makes you say that?

[mach1mustang351]

In CA they pressurize the tank with Nitrogen and look for evap system leaks.  I know the have to bypass this test on the dual tank vehicles.  I'm not sure if it is because of the volume of Nitrogen needed or why they bypass the test. 

[mrnda]

Zambonie---------I was refering to the evap test that is performed during the smog check process.

[VileZambonie]

Dual tanks is irrelevant though. That shouldn't make a difference on the test.

[mrnda]

That is part of the quesiton, i plan to put in the dual tanks.  I have heard from multiple people that with dual tanks the test could not be performed.  I suppose i will have to contact a smog shop and post the response for tribal knowledge.

[mach1mustang351]

The correct answer is they do not evap test the dual tank vehicles.  I understand they CAN do it but by the smog rules they do not.  You can call Smog shops or your local referee and they will tell you the same.

[mrnda]

Mach1------------Thanks for the response it is much appreciated.

[ehjorten]

They don't test the dual tanks in Washington either.  Just went through this last December on the Crew Cab.