Help Understanding Monza Fuel System

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Help Understanding Monza Fuel System

Postby fas141 » Thu Aug 19, 2021 8:37 am

Hi All,
I have a 77 Monza factory V8 car. Basically all stock but with a 350 in it now, but not running. Could someone explain the fuel system to me? I thought I would just run a regular fuel pump off the engine block but see the owner before me blocked it off. So I thought he was doing an aftermarket electric pump. Then I read Monza's have in tank fuel pumps. So what about return lines and regulator etc? Can someone school me please and thank you.
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Re: Help Understanding Monza Fuel System

Postby cjbiagi » Thu Aug 19, 2021 5:40 pm

Stock V8 Monza's had a electric pump in the tank that produced 5-7lbs prressure so no regulator was required. There was a second line going to the tank which was part of the evaporative emission control.There was no return line, although the emission line can be used for one if the canister is removed. The fuel pump is fed from the oil pressure switch near the distributor. It receives power either while cranking or after the engine starts and there is at least about 7lbs of oil pressure. This is a safety feature so the fuel pump is disabled if the engine stalls after a accident, it prevents fuel from continuing to be pumped. There is limited clearance for a mechanical pump, sometimes the frame needs to be clearanced if you switch to that.
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Re: Help Understanding Monza Fuel System

Postby fas141 » Thu Aug 19, 2021 8:44 pm

Thanks Clyde, that helps. I would like to keep the cars fuel system stock, since it appears to be all there. The canister is still there. On it, it has one line that says "Tank" so I assume that is the line you mention back to the tank. The other says "Carb" where does that go? to the vacuum port? or was it an EGR on the factory 2bbl? I do not have the factory 2bbl and will run a 4bbl (not sure which yet)
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Re: Help Understanding Monza Fuel System

Postby cjbiagi » Thu Aug 19, 2021 9:06 pm

I believe it went right to the carb, may have gone to a vacuum switch to that were used on the thermostat housing. My car is not stock so maybe someone else can verify where it goes.
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Re: Help Understanding Monza Fuel System

Postby 74_Vega_GT » Fri Aug 20, 2021 9:17 am

( and there is at least about 7lbs of oil pressure.)....from above...
~ The oil pressure switch closes at 3psi minimum....I think I read.
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Re: Help Understanding Monza Fuel System

Postby cjbiagi » Fri Aug 20, 2021 4:12 pm

That could be, I know it's pretty low. Basically it just turns off if engine is not running unless you are in the "start" position on the ignition switch.
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Re: Help Understanding Monza Fuel System

Postby zeke » Fri Oct 22, 2021 11:10 pm

Chris

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