Carb fittings

[psg]

On my '78 spider 1.8 on the drivers side in the engine compartment on the inner fender there are two white/yellow plastic boxes. One of the boxes has hoses attached to the carb and the other when I received the car (not running) has no hoses attached. Should these be connected to something. It is the front box that is not connected to anything. The boxes have a large hose fitting on the underside in the back and a smaller fitting on the top front. paul

[manoa matt]

Those are electrovalves. The front one is for the EGR system. Depending upon your state's emissions regulations you may or may not need it. The rear one is the fast idle electrovalve. The fast idle system keeps the idle higher when you rapidly decelerate or when going down a hill, so the high vacuum created by the engine does not suck raw gas into the intake. That is what produces that loud repetitive popping noise. There is a diaphragm port on the carb at the front passenger side. The hose should go from that port to the front of the electrovalve then another hose out the back of the electrovalve that goes to a fitting on the intake manifold below the carb. The diaphragm housing has an adjustment screw on the top. There is also a black test button mounted between the electrovalves. Once the hoses are hooked up you can test and adjust the system.

Start the car and let it warm up to operating temp. Pull on the accelerator linkage to get the RPM's above 2500 then push in the button and let go of the accelerator linkage. The rpms should drop and stay at 1600 with the button pushed in. Screw in or out the adjustment screw to attain the proper rpms.

[psg]

thanks for the response just what I was looking for. psg

[lvacordian]

Thanks very much for your post; I've been racking my brain over this for the last week. The emissions schematics for the manuals that I have (Haynes & Fiat North America) aren’t the easiest to understand.

I understand what you were saying about the fast idle electro valve, and it's vacuum connections, but what about the EGR electro valve to the left of it. I believe one of those connections branches off to the to the EGR valve but what about the other connection on the other end of the valve. Where does that connection go to?

I live in California and as you know we have ridiculous emissions standards, so I'll probably need to hook that up.

Tom
78 Fiat Spider

[manoa matt]

Tom,

I'll see if I can find a diagram for that, I removed mine due to no emissions testing in my area.

Matt