Wow I should have gotten a vacuum gauge when we got this jeep. I had no idea how useful they can be to diagnose problems.

Unfortunately, there seems to be a problem at the source. (At operating temperature)



The needle vibrates but holds pretty steady at under 14. I’ve only watched a couple videos on this. But that sounds like the timing is slow?

I also found that the check valve above the source does not hold a vacuum.

But where do you guys get check valves? Part number? The ones they gave me at autozone don’t fit.

 

Those check valves are Napa part #2-1015.

Had to order the second one. Be here tomorrow.

In the meantime I tried the vacuum gauge on the manifold nipple that goes to the map sensor. Same result except the engine kept trying to increase idle and would get up to about 16i nHg before dropping back down to 13.5.

The line to the MAP seemed to hold but does not hold pressure after sitting a few minutes.

The MAP sensor itself seems to hold vacuum better. But the tube didn’t fit very tight and it dropped a tick while waiting a few minutes. Maybe just the tube.

On the passenger side the check valve also failed. Ao did the line coming off of it with the elbow.

The T at that location held a vacuum.

That line with an elbow on the T that failed seems to go into the firewall to the climate control.

I’m gonna cry. I hope I can find a tube I can reach that just isn't seated by looking under the radio.

And why am I still inly getting 13.5 inHg at the throttle body? Is that a separate issue?

 

Solved the low vacuum at manifold source issue.

I’m at 7000+ ft in elevation! It says here that vacuum is reduced by 22.8% and I should add about 6- 7 to get the actual reading.

https://www.asesystems.com/vacuum-li...-vacuum-level/

So that steady 13.5 Hg at the intake manifold is good news. I think.

 

Well, this HPSI vacuum hose kit sucks.


It’s not long enough to follow the original path to the evap canister. The instructions say to cut off four inches of the tube on the right to make an adapter for the CCV too.

Is this why I see pictures of jeeps with all the messy tubes all over the engine bay? WTF?

Anyone know a good alternate routing for these?

 

They labeled these two F and K because they’re both too F#%King short.

 

Here’s the way they it was going to be with the amount of hose they gave me. I didn’t like the sharp bend and it resting on the master cylinder.

They did not have the same hose a Napa. But close enough. $15+ a foot! And its rubber wrapped in silicone! Whatever. Got it done.


Replaced all this old brittle tubing. Feels good. Like taking a shower after a week camping. And I never would have found the break if i wasn't replacing it all. It was up under the rim of the firewall behind lots of other stuff.

If you zoom you can see that one side of the tubing is worn so flat that it wore into the center.


Purdy. And OMG I didn't know so much of that mess was vacuum lines until I turned them blue. Now I can keep an eye on them better. The A/C is working so far. Vents blowing out the front. Now let’s see if I can break it by driving the bleep out of it up and down a mountain every day.

 

What a difference!! Looks good too. Well done!!