Bredd1

Is the device in the vacuum line near the throttle body a check valve or damper? My service manual calls it a damper but when I went to get a new one at the auto supply store, the device that looks exactly like it is labeled as a check valve. Is it some type of damper or is it a check valve or is it the same part? When I think of a damper, I consider a device that restricts or regulates flow and a check valve is a device that prevents/stops reverse flow.

vetteoz

Helps if you mention year model when asking questions;
many differences over 12 years.
The only check valve should be on the vac line beside dist on TPI cars
or on side of intake on LT1's.

Bredd1

Its L98 engine(86/87), its a swapped engine and not sure exactly which year, it does have aluminum heads. I was going by a picture shown in the service manual that has the check valve at the intake/TB. One of the ports off the check valve connects to the bottom of the TB, this vacuum line was missing on car causing the engine to "hunt" when idling. In an attempt to correct the hunting, I wanted to connect my vacuum lines as shown in the picure from the manual. Seeing as though this must be incorect, is there a diagrahm available showing the correct vacuum line connections for my engine.

Bredd1

[QUOTE[/QUOTE]

This is the way my engine is, with the check valve behind the distributor. One line goes the fuel regulator and the other goes to a vacuum line running in the wiring harnes. Is that correct?

toptechx6

The three port one way check valve is designed to maintain vacuum to the climate control system and cruise control during brief periods of low engine vacuum such as WOT. The supply hose should come directly from the intake manifold, near the fuel pressure regulator, but not connected to it. The other two ports supply the climate control system and cruise servo.

leesvet

The ck is supplied by 1 of the 2 vac nipples on the rear plenum. The 2 nips on the ck go to the cabin supply line behind the dist, and the other runs over toward the dist where it supplies the cruise control and merges with the evap lines.

Yes, you DO have a damper in the line from the Tbody that runs across behind the alt & air pump. The damper is just an orifice of sorts to regulate how hard the vac can pull on that line. You can find them in the "help" section at the store. Its not totally necessary, but if you want factory then yes, it don;t hurt to have one. Thats a "ported" vac source under the T-body that has variable vac from the different loads and butterfly positions in the Tbody. It changes with conditions. IIRC the vac bulb (storage) is for the cabin system. The evap system used larger hoses that serve the same purpose to store enough vac to operate the system should there be a sudden but brief drop in vac like when the throttle changes position suddenly. If it were not for the ball and the damper your a/c vents would change everytime you stepped on the gas and there is the risk that the diaphrams in the vent actuators could be blown out with too much surge in vac. (damper).

You need to find yourself a FSM if you really want to keep things as they should be. A CD version would be perfect....cheaper and they cover what you need.
That will have all the wire layouts and vac diagrams for that engine. I guess someone could copy the sections needed since this is a conversion and the rest of the book may not apply.

Bredd1

I went through and checked all the vacuum lines and made connections same as the diagrams I found online. I did find that the EGR vacuum circuit was plugged off and not connected. Also I found that the air switching valve and air control valves are not installed. Are these valves needed for the engine to operate properly?

leesvet

If you have smog test YES.
If you still have a CAT, BIG YES.

The air valves send fresh air to the cat OR the mainfold depending on temps and conditions. IF the cat cannot lite off when its flooded with rich exhaust gases, it can cook inside and the substrate can melt away and clog the thing. It can plug from the excess carbon and that kills CATS quick.It needs the fresh air flow to fuel the burn of the chemical reaction between the gases and the substrate to create harmless water vapor.
No Cats, no worries.

Assuming the air pump is still there....its doing nothing without the diverter and switching valves. All of the exhaust plumbing needs to be there as well. You REALLY want that EGR working too. That helps keep the engine from melting down from excessive combustion temps. Helps with engine knock as well. If all that is missing, look to see if the knock sensor is there...and ESC and all the other things that bubba hybrids end up missing...

Bredd1

I have CATs, preCATS and main. The AIR system is all removed. I did reconnect everything for the EGR system. Where would the air valves normally be located?

leesvet

wow...lots of plumbing...

They (valves) are on a bracket thats attached to the top of the water pump and hangs them toward the compressor. There is a vac line from the rear plenum (2 nipples) that runs up front to split to supply the 2 valves. On valve has the 3/4 hose from the air pump. The other has hose from the other valve, and the silencer, and to the manifold pipe system. There is a hose straight to the Cat air supply pipe. Its the main cat that gets the fresh air. Follow the supply pipe from the cat. Its been capped off somewhere...
If you still have the a.i.r.system exhaust manifold pipes mounted it should'nt be too bad to restore. This has a series of check valves that have to work.
You're going to need to look at a working system to study the pieces. I am not sure a pic would do justice to the complex valve arrangement.
Is the Evap system all there? charcoal can and lines? steel lines to tank and all that good stuff? Thats needed as well. I hope the PCV is intact.

Bredd1

Is the AIR system necessary? All of this already removed when I purchesed the car and the car ran fine. It was after I replaced the head gasket that I started having idle problems and the engine kind of lobe. The idle is much better but the engine still wants to hunt a little bit.

leesvet

if you want it stock again with the cats working trouble free and the other systems al connected as they should be...
Depends on if you want your cat to live long or not......

Bredd1

Not too worried about it being stock. Just trying to get the engine to run smoothly. Does the A.I.R. System need to work now that I've got the EGR connected?

Cliff Harris

The A.I.R. and EGR systems are completely separate.

The vacuum line under the throttle body goes to the EGR solenoid (mounted on the thermostat housing) and from there to the EGR valve.

The A.I.R. divert and switch solenoids determine where the A.I.R. air goes. Divert solenoid sends air to the outside world (diverted) or to the switch solenoid. The switch solenoid sends air to the pipes in the exhaust manifolds (where they attach to the heads) or to the rear catalytic converter (to help it burn off emissions).

Bredd1

I'm going to continue to work on the vacuum lines to ensure I don't have any leaks. I'll let you know how it turns out.

leesvet

Like I said, you can live without the a.i.r. system but you need to eliminate the cats so they do not melt and close off the exhaust system. That could be happening right now adding to the difficulty in getting it to run well.

AIR simply fuels the CAT. Thats all. BUT, if you have a cat you need the AIR.
A plugged exhaust is pretty much the end of the trip...and never happens at a good time.

Bredd1

Thanks leesvet, I understand your point.