My first Spider! Unidentified part

[moses]

Just started restoration on my first Spider, it's a 1976 CS1.

I've got a part that I can't seem to find in either the Haynes manual or the factory manual. It's on the driver's side of the engine bay along the wall. It appears to have one hose running to the master cylinder and the other hose was destroyed and I can't see where it was supposed to lead to.





What is this?

[DieselSpider]

Looks like an electrically operated vacuum valve. If one end goes to the brake booster then the other end goes to the intake manifold to regulate vacuum to the power brakes. The hoses need to be gone through on that one before you try to make any assessment of the brakes or carbs. Is this on a currently running vehicle?

[moses]

No, it has a no spark condition, which I've determined to be either the distributor/distrib cap or plugs/wires.

I'm assuming this will cause a decent vacuum leak. Do I need to be worried about attempting to start it with that line being demolished?

[DieselSpider]

No, it has a no spark condition, which I've determined to be either the distributor/distrib cap or plugs/wires.

I'm assuming this will cause a decent vacuum leak. Do I need to be worried about attempting to start it with that line being demolished?

Any large line broken like that is a conduit to suck dirt directly into the intake manifold so you do not want to start it with any large lines in that condition especially if you are hoping to avoid rebuilding the engine. Even if it does not ingest dirt the line being open can cause the engine to run lean enough to potentially burn valves or piston tops.

[Ramzi]

Its a fast idle valve... If you have an owners manual or original shop manual.. its explained there

[DieselSpider]

Is it connected to a tee on the brake booster or straight to it? A fast idle vacuum actuator valve should not be plumbed to act directly on the brake booster itself but should be set up with one hose going to a good vacuum source and the other to the fast idle pot on the carb. It should have electrical connections to the clutch pedal and the transmission along with possibly an emissions test switch on the fender/firewall.

This discussion is on the Spider 850 however operation should be similar:
http://forum.fiatclubamerica.com/viewto ... f=8&t=3631

Regardless of its purpose the integrity of the vacuum lines need to be restored before running the engine for any length of time or making any adjustments aside from a valve clearance/lash adjustment. Too many make the mistake of adjusting the valve clearances last and then have to redo or undo their last carburetor adjustment. Don't forget to check the fast idle vacuum pot on the carb for leakage while your at it.

[moses]

Its a fast idle valve... If you have an owners manual or original shop manual.. its explained there

I've got the factory shop manual and the Haynes manual but I can't seem to find any mention of it.

[Ramzi]

As I recall and confirming w/ Csaba it was used to add to air on deceleration - it is controlled by switches on the transmission and clutch pedal. I will have to look at some OE manuals I have at home to confirm this.. but the button behind the valve in the photo (above) was also used to actuate the fast idle for testing that . If I have time, I'll dig it up later this week and post the pages

R

[moses]

Anybody have any idea where the broken hose led to? A picture would be great. The vacuum leak is definitely causing a rough idle.

[DieselSpider]

Anybody have any idea where the broken hose led to? A picture would be great. The vacuum leak is definitely causing a rough idle.

The discussion I provided the link to had the vacuum pot on the carburetor pictured in one of the replies. You need to verify if the other end is connected directly to the brake booster or is just sharing the same vacuum line with a Tee or Y in it.

Below are some of the relative pics and diagrams.

Compensating vacuum device on carb:


Basic diagram of complete system: