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Please walk me thru checking the check valve just in case I misunderstand how it works.
The two nipples that are on the same side of the large part of the body (that can be determined to be visually connected), are for the vacuum reservoir and the HVAC/T-case connections. The nipple by itself on the other side of the large part would be for the intake manifold/vacuum supply.
This picture below illustrates how I think it works. Note that the pressures are relative to atmosphere; i.e. "not-as-low pressure" means only a small vacuum and the pressure is only a little bit lower than atmosphere. "Even lower pressures" would be for when there is lots of vacuum at the engine such as when it is idling or cruising.
So, if you plug one of the outlet nipples that go to the HVAC/T-case or to the vacuum reservoir and then pull vacuum on the other outlet nipple, the valve should hold a vacuum. This scenario would be equivalent to the engine being off or pulling hard and the vacuum system relying on the reservoir.
This is exactly how I thought it should work, that being said, it seems the vacuum reserve isn't adequate on those long uphill runs. I am going plug the main vacuum line where it plugs into the check valve and give it a go and see if that stops the stuttering/power fluctuation issue under a heavy load and work from there......wish me luck.
This is exactly how I thought it should work, that being said, it seems the vacuum reserve isn't adequate on those long uphill runs. I am going plug the main vacuum line where it plugs into the check valve and give it a go and see if that stops the stuttering/power fluctuation issue under a heavy load and work from there......wish me luck.
OK, I figured you had the same understanding I did. But as we all learn, sometimes the hard way, it is worth checking even the unlikely stuff. If the valve ends up being good, I wonder if there is a slow-leak somewhere? I forget, did you put the zip-ties on any more of the fittings to make sure you eliminated all possible leaks from them?
Going to take the reservoir, HVAC and 4WD out of the loop and start from the back side and work out from there in hopes I can isolate the problem area. That should at least tell me if I have a different issue causing the stutter and roaming RPM under a load.......I hope.
UPDATE
I have narrowed the vacuum leak down to the HVAC, I'm thinking the plastic line where it goes through the firewall with wiring has cracked somewhere in the harness, will tear into that this weekend. Unfortunately after taking all the vacuum accessories out of the loop it did not do anything for my issue with stuttering/skipping and hunting RPM. Guess I will start looking at fuel pressures and such, not going to dive into this too deep as it is getting a marine intake this fall.
Hi Christine,
My Bravada has a check valve in the same location as these pictures. My check valve is smaller than the one in the picture. I have another valve, new, that looks as the one in the picture. I'll attach a picture. Do you think this valve is good to use?
Thanks
Hi Christine,
My Bravada has a check valve in the same location as these pictures. My check valve is smaller than the one in the picture. I have another valve, new, that looks as the one in the picture. I'll attach a picture. Do you think this valve is good to use?
Thanks
RTJ49
Yes that looks like the right valve and it is easy enough to give it a try.
BTW, I suspect you replied to the wrong thread as this was started by someone else (although with similar question). It is considered bad form to hijack a thread so just be careful not to make the mistake in the future.
