Help with Vacuum Hoses

76green · 05-11-2006, 04:00 PM

I have been looking at the vacuum hose diagram and I feel like I am definitely missing some parts that I PO might have taken off. Here are some pictures...I am wondering about the two holes where the throttle body mounts and is what the decel valve looks like. Any help would be appreciated...

Dave at Pelican Parts · Dave at Pelican Parts's Garage

I have no clue what that thing in your first picture is! It looks like it has two hoses (air? fuel?) and a couple of wires going to it. It's not a stock part that I am familiar with.

The second shot shows two of the fittings on the manifold. In the 74, one is connected to the PCV valve on the oil filler. I am not sure the 76 has a PCV valve (some of the crankcase ventilation stuff is different on the 75-76 cars, and I'm not certain about which late cars had what), and if not then you would not hook up the manifold to the oil filler.

I would hazard that the small port (the one on the 73-74 manifolds seem to be bigger than that one is) would go to the decel valve's small fitting. The larger one would go to one of the two large fittings on the decel valve. I can't find a reachable pic of the decel valve--the Rennlist Member server seems to be hanging up or dead.

The last picture shows the Auxiliary Air Regulator. That fitting should get plugged into the intake manifold right at the cold-start valve. Check for a fitting there--on the left-rear corner of the manifold. The other fitting on the AAR (hidden by the hose in the pic) would connect to the air cleaner. If you were to turn the AAR around 180 degrees, the two fittings would match the angles on the 74 hose diagram more closely.

--DD

76green · 05-11-2006, 04:44 PM

can you post a picture of a decel valve...i don't think I have one!!!

The first picture is the line off the throttle body and the line off the nipple closest to the distributor...(dashpot???) and is there supposed to be a line on the other side of the dashpot...thanks for your help again...

Dave at Pelican Parts · Dave at Pelican Parts's Garage

The line off the distributor dashpot that points away from the distributor body is the advance line. Your throttle body does not have a fitting on it for vacuum advance, therefore you do not hook up the advance fitting on the dashpot to anything. Lots of 74+ 914s are this way, and have advance fittings that aren't connected to anything.

--DD

76green · 05-11-2006, 05:01 PM

what does the decel valve do? how important is it? where do I get one, I just saw a picture and I know I don't have that on this car. The two holes off the manifold were just plugged...thanks again for the feed back...

sean_V8_914 · sean_V8_914's Garage

it reduces emisions under deceleration by adding fresh un-metered air

http://members.rennlist.com/pbanders/decel.jpg
or
http://members.rennlist.com/pbanders/DJetParts.htm

Dave at Pelican Parts · Dave at Pelican Parts's Garage

I think I may have figured out what the mystery component in the first pic is. This is or was an AC car, right? Looks like the engine tin on the right-front corner was cut for the compressor.

It might be a high-idle solenoid--when the compressor kicks on, it would open up and let extra air go through. That would raise up the idle RPM, in theory about as much as the load from the compressor would lower it.

--DD

76green · 05-12-2006, 03:53 AM

I think you are right Dave!...It does go to the air compressor for the air conditioner (which I don't believe works)...thanks for all the help...

Should I find a decel valve? Is it OK to run the car without it...I noticed previously it would backfire on deceleration...Would that help things out? Thanks again...Brent

Dave at Pelican Parts · Dave at Pelican Parts's Garage

The decel valve might help with the backfire, but probably not. It is not a completely necessary component, but I feel it is good to have...

--DD