jai05002

Hey all,

I've got an '88 Cherokee Chief 4.0, and I've been trying to get the idle a little smoother. Unfortunately today, while disconnecting the MAP sensor vacuum line (the one from the MAP sensor to the intake), the plastic on the line snapped, probably due to age . Now I've got it rigged together with makeshift tubing made out of an old CAT5 cable, but thats obviously not going to last. I've searched and searched NAPA, AutoZone, etc for the part number for just the MAP vacuum line, but have failed to find a part number. Has anyone replaced this line, and if so, would you happen to have the part number for NAPA or such? Any help would be greatly appreciated. Thanks!

--Johnny

jai05002

Nevermind, answered my own question. Could not locate the vacuum hose anywhere, so I salvaged the MAP sensor end and the elbow to the intake, and found some 4mm hose to fit snugly around the existing tubing, XJ runs better than ever! Here's a picture of the "new" hose.

4literranger485

I apologize for bringing this back from the dead, but I had the same issue today. Thanks for the help on the fix, but I have a question

What is the additional port for on that black grommet that goes into the throttle body? Should I plug it, leave it open, or does something else need to be hooked to that port that I am missing? Thanks in advance for any help!

Bustedback

Post a picture of what you're talking about.

4literranger485

Here is the best shot I could get. Thanks in advance for any help!

Bustedback

If it's sucking air you should cap it off as long as nothing goes to it.

4literranger485

I was wondering if something is supposed to go to it lol. The vacuum diagram in the manual and under the hood only shows the MAP line going to the T-body and nothing else. I think I'll just cap it per recommendations, it seems to idle a smidge better when I plug it with my thumb.

Thanks

cruiser54

It just helps retain the connector. A hole that has no vacuum.

4literranger485

I just got back in from fixing the line and realized that I bet I looked pretty smart shoving my thumb over it and imagining the rpms changing ever so drastically. Live and learn I guess! lol

cruiser54

So, have those voices still been bothering you since you got out of the institution? LOL. Welcome to CF!!!!

I'm also known in some circles as Major Brainfart. A cutesy nick-name given to me by me fellow members.

gusjdj

Hi all,
I'm working on a rough idle..not that bad, but noticeable...Thanks for the info on the extra hole in the gromet...thought for sure that was my problem..what I did find..The 2 small oh...guessing here..6/32 bolts that hold the map sensor in place are missing the nuts that hold it in place...so it's rattling around..wondering if it'll make a difference to tighten these up..I'll let ya know here in a few...wonder if they create a seal when tight...thanks for any info...
Jay

scottmphoto

I had this problem on my last XJ. What I did was to get a piece of metal brake line and use it instead of the plastic. I also had a problem where the plastic vacuum line just above the rubber connector on the intake would melt shut every 2-3 weeks. This was the fix for that too. I don't remember the size of the line but it was just a little bigger than the stock vac line. Pretty soon, every plastic vac line in my Jeep will be replaced with steel.

cruiser54

[QUOTE=gusjdj;2856345]Hi all,
I'm working on a rough idle..not that bad, but noticeable...Thanks for the info on the extra hole in the gromet...thought for sure that was my problem..what I did find..The 2 small oh...guessing here..6/32 bolts that hold the map sensor in place are missing the nuts that hold it in place...so it's rattling around..wondering if it'll make a difference to tighten these up..I'll let ya know here in a few...wonder if they create a seal when tight...thanks for any info...

What year?

gusjdj

1987 Jeep Cherokee Laredo 4.0 Straight 6

cruiser54

Loose MAP nuts aren't a problem.

Spraying something like carb cleaner around your vacuum lines at idle will assist you in finding vacuum leaks.

Make sure your intake manifold bolts haven't loosened up.

I would click on the link in my signature and do Posts 1 through 5 and even 27 if you can solder. < before doing anything else.