79 carb manifold upgrade

[barnesjtsl]

I'm getting rid of the ADHA and the dual plane manifold.

Installing a 78 single plane and a 32 ADFA.

What do I do with the Gulp Valve? I don't want my car to start backfiring. Will backfires be a problem without the Gulp valve?

Thanks,

barnesjtsl
Peoples Republic of Portland OR

[18Fiatsandcounting]

The gulp valve was part of the air injection system (smog pump), so if your engine no longer has this system, then you don't need the gulp valve. In a nutshell, the gulp valve is closed under normal driving, but if you let off the gas, it opens up and directs some of the air from the smog pump to the intake manifold, thus leaning out the mixture (and preventing the backfire).

Unless the air injection rail and the ports into the exhaust ports have been cleaned, there is a very good chance that they are plugged up anyway and so the gulp valve again isn't adding much value.

Give it a try without the gulp valve and see if there is any backfiring.

-Bryan

[barnesjtsl]

Thanks 18. I'll give it a try without it.

barnesjtsl

[barnesjtsl]

The gulp valve was part of the air injection system (smog pump), so if your engine no longer has this system, then you don't need the gulp valve. In a nutshell, the gulp valve is closed under normal driving, but if you let off the gas, it opens up and directs some of the air from the smog pump to the intake manifold, thus leaning out the mixture (and preventing the backfire).

Unless the air injection rail and the ports into the exhaust ports have been cleaned, there is a very good chance that they are plugged up anyway and so the gulp valve again isn't adding much value.

Give it a try without the gulp valve and see if there is any backfiring.

-Bryan

I think you are confusing the Gulp valve with the Air Injection Check Valve that screws into the top of the Head between the valve covers. The Gulp valve is on the firewall on the intake side and has a hose that goes from the Gulp valve to the intake manifold.

Do you know what it does and can I get along without it?

barnesjtsl

[18Fiatsandcounting]

I think you are confusing the Gulp valve with the Air Injection Check Valve that screws into the top of the Head between the valve covers. The Gulp valve is on the firewall on the intake side and has a hose that goes from the Gulp valve to the intake manifold.

Do you know what it does and can I get along without it?

barnesjtsl

Is your '79 spider a Calif. car or a 49-state version?

What you're describing on the driver's side firewall sounds like the electrovalve for the fast idle system on the carb. Properly installed, it has one vacuum hose from the intake manifold to the electrovalve, and one vacuum hose from the other side of the valve to the carburetor. It has an electrical connection at the bottom. It's function is to raise the idle speed of the engine under certain conditions, namely when the clutch is engaged and the car is in 3rd or 4th gear. Yes, you can get along just fine without it unless you have to pass a smog check.

Part of the problem is that there are a ton of terms for the various emissions valves: gulp valve, diverter valve, EGR valve, reed valve, check valve, electrovalve, and a few others that I've forgotten. The 1979 spider had just about all of these and was a bear to maintain until fuel injection came out in 1980 in Calif. and elsewhere in 1981.

-Bryan

[barnesjtsl]

I think you are confusing the Gulp valve with the Air Injection Check Valve that screws into the top of the Head between the valve covers. The Gulp valve is on the firewall on the intake side and has a hose that goes from the Gulp valve to the intake manifold.

Do you know what it does and can I get along without it?

barnesjtsl

Is your '79 spider a Calif. car or a 49-state version?

What you're describing on the driver's side firewall sounds like the electrovalve for the fast idle system on the carb. Properly installed, it has one vacuum hose from the intake manifold to the electrovalve, and one vacuum hose from the other side of the valve to the carburetor. It has an electrical connection at the bottom. It's function is to raise the idle speed of the engine under certain conditions, namely when the clutch is engaged and the car is in 3rd or 4th gear. Yes, you can get along just fine without it unless you have to pass a smog check.

Part of the problem is that there are a ton of terms for the various emissions valves: gulp valve, diverter valve, EGR valve, reed valve, check valve, electrovalve, and a few others that I've forgotten. The 1979 spider had just about all of these and was a bear to maintain until fuel injection came out in 1980 in Calif. and elsewhere in 1981.

-Bryan

This is what I'm talking about. Are we talking about the same thing?

https://www.midwest-bayless.com/p-6808- ... 80-oe.aspx

barnesjtl

[18Fiatsandcounting]

This is what I'm talking about. Are we talking about the same thing?

https://www.midwest-bayless.com/p-6808- ... 80-oe.aspx

I'm not familiar with that, so I can't offer any help. Sorry.

-Bryan

[Nut124]

Your car will run just fine w/o it.

The only reasons to put it in would be if required by state law (inspection, test) or if doing a 100% original resto.

[barnesjtsl]

Your car will run just fine w/o it.

The only reasons to put it in would be if required by state law (inspection, test) or if doing a 100% original resto.

Thanks, do you know what this thing does?