mystery pump
- Thread starter Pattracy
- Start date
Pictures or details? Connects exactly where on the carb?
There shouldn't be any 12v pump on a stock '75, so you are either looking at something totally bizarre that some previous owner did (Oh, the stories we could tell... Don't get redbull started!) or looking at something else like a electrically controlled vacuum valve. But I can't think of anything like that on a '75 either so I'm still confused - hence the request for pictures and/or details.
probably a vacuum valve
My 78 had an off-white plastic device in that location with a couple hoses and wires connected to it. You can see it in this picture on the back firewall slightly right of center.
I am putting in a 1500/FI and sold a lot of the carb related parts to Zonker, so I could not find that part here to take a better look at it. I will see if I can find any more pictures or an actual description of what exactly it is.
My 78 had an off-white plastic device in that location with a couple hoses and wires connected to it. You can see it in this picture on the back firewall slightly right of center.
I am putting in a 1500/FI and sold a lot of the carb related parts to Zonker, so I could not find that part here to take a better look at it. I will see if I can find any more pictures or an actual description of what exactly it is.
dragonsgate
True Classic
What is written on the label? Are you sure it is a pump? Maybe it is a solenoid that opens and closes valve. Does the wire lead to a thermal switch?
russloveslife
Daily Driver
pump, idea
on my car the pump you are describing was connected to a factory button near the shocker mount and it would activate the pump to raise the revs in the car when it was pushed no sure why it was needed but occasionally i would use it while i was looking at engine bay and wanting higher revs, just my 2 cents worth for what its worth
on my car the pump you are describing was connected to a factory button near the shocker mount and it would activate the pump to raise the revs in the car when it was pushed no sure why it was needed but occasionally i would use it while i was looking at engine bay and wanting higher revs, just my 2 cents worth for what its worth
In the pic you can see one line goes to the top left of the carb. The other line you can't see goes below the carb, into the intake manifold. Probably some kind of vacuum solenoid, I guess. It says 12v and webber on it. If you zoom in on the first pic you can sort of make out what it says.
Thanks Dave, you just complicated matters. I don't have #16, in the picture. Also once I figured this out I was going to ask, why I have 4
1/4" lines in my head, all 4 cut off and crimped over, one for each cylinder. Now I see that that is #15 in your picture, and I don't have that either.
1/4" lines in my head, all 4 cut off and crimped over, one for each cylinder. Now I see that that is #15 in your picture, and I don't have that either.
dragonsgate
True Classic
The crimped lines into the head are air injectors that worked in conjunction with the smog pump that is missing. Number 15 in Davevoss' picture is the part that has been cut off and crimped' I can't find the picture
Davevoss posted in my books but I am more than pretty sure there are parts gone in the smog system and the hook up on your engine is just a convenient place to put all the left over hoses. Also from what I gather from Dave's picture that is not a pump but a solenoid valve activated by a sensor on the engine that opens and closes at specified temperatures.
Typical Emissions System Diabling
A lot (maybe most) of the surviving Fiats still on the road from this era have some or all of their original emissions components removed or disabled. It was Fiat's way of complying with the Federal (and CA) standards of the day, but honestly most of the time the engines ran better with these systems disabled.
IIRC, the electrovalve needs voltage to open, and so if it is disconnected, then the vacuum hose from the intake manifold is not actually doing anything. If that electrovalve were energized, it looks like manifold vacuum would be applied to the carb fuel bowl vent (if I'm looking at your picture correctly) which would not be a good idea, as it could affect flow inside the carb, possibly causing the air/fuel mixture to become too lean.
BTW, the diagram that I posted is in the Fiat Emission Control Systems publication, issued in the late 1970's to Fiat dealerships.
A lot (maybe most) of the surviving Fiats still on the road from this era have some or all of their original emissions components removed or disabled. It was Fiat's way of complying with the Federal (and CA) standards of the day, but honestly most of the time the engines ran better with these systems disabled.
IIRC, the electrovalve needs voltage to open, and so if it is disconnected, then the vacuum hose from the intake manifold is not actually doing anything. If that electrovalve were energized, it looks like manifold vacuum would be applied to the carb fuel bowl vent (if I'm looking at your picture correctly) which would not be a good idea, as it could affect flow inside the carb, possibly causing the air/fuel mixture to become too lean.
BTW, the diagram that I posted is in the Fiat Emission Control Systems publication, issued in the late 1970's to Fiat dealerships.
Carb Fuel Float Bowl Vent
This should either be routed to the charcoal canister (if present) or left open to atmosphere, it is important that it not be capped or otherwise plugged to prevent heat rise from creating pressure above the fuel level, as that will cause fuel to be pushed through the jets, rather than drawn through during normal running. Carburetor flooding after shutdown on a hot day can be a common issue if the vent is blocked.
This should either be routed to the charcoal canister (if present) or left open to atmosphere, it is important that it not be capped or otherwise plugged to prevent heat rise from creating pressure above the fuel level, as that will cause fuel to be pushed through the jets, rather than drawn through during normal running. Carburetor flooding after shutdown on a hot day can be a common issue if the vent is blocked.
Where it's legal, a systematic and thoughtful desmogging of the early cars can be an improvement, as the pollution control equipment was engineered in as afterthought. There are some old threads about how do this, what you can lose, what you may want to keep, and what you have to keep (mostly the fuel tank vent system).