Connecting a Vacuum guage to the intake manifold

[shepherd]

Hi again!

So I have my 65 Jeep home. I posted originally here - http://www.jeep-cj.com/forums/f7/looking-advice-turn-signals-65-cj5-13111/

I have since realised that the turn-signals ( now installed ) are the least of my worries and problems.

The vehicle has a very rough idle, and will stall if I don't give it a little gas every ten seconds or so. Sometimes it idles for up to three minutes, and sometimes it's just always on the verge of a stall. The Previous Owner told me the carburetor was rebuilt and the timing was done. I don't disregard the possibility that he may be full of ... however. The vehicle has to turn over quite a few times to finally get started, and sometimes it just makes a high pitched whirling noise, which I presume is the starter motor failing, once I DO finally get it started, it will start right up on the first or second turn after that, unless it is really cold or my battery is dieing ( both common occurances )

I have a vacuum guage which I was advised to connect with a T-adapter to the intake manifold to diagnose engine problems ( apparently it will allow me to interpret some other nifty things as well ). The problem is that I do not know where the cable that I want to tap into is.

I've included some pictures, unfortunately I couldn't get any really good shots because of the strong sun, and for some reason this website rotates the pictures whichever way it wants, I will try to take some better ones later. Eye-candy! let me know thoughts or observations.

Thanks for the help, as well.

Regards

 

[derf]

First off, you don't want to cut a cable, you want to cut a vacuum hose. They are hollow rubber hoses that go from the manifold or carburetor to other things under the hood.

On an old Jeep, there's no telling what hoses are connected and if they're connected properly.

A diagram from a factory service manual would be your best bet for finding where the hoses are supposed to go. You should be able to find something around here I think. Get those figured out first and set up correctly. From there you can find a good manifold vacuum hose, cut it, stick a T into it and attach the open end to your gauge.

 

[jasonmark1993]

Fuel pump could be failing allowing. This may explain why you have to crank for a long time on initial startup. A fuel pressure test should always be done when having driveability problems.

I like to see fuel pressure while running and driving. You should be able to get a cheapo fuel pressure gauge and even the valve/adapter at Vatozone or NAPA.

 

[Niedhogg]

What a cool old Jeep... This model won't have too many vacuum lines at all, look for small hoses or tubing or any small nipples that come directly off the intake, and that is where you will want to connect your vacuum gauge. It is a good way to adjust your low idle setting. I am not too familiar with these older carbs, but there should be a low idle mixture screw somewhere near the base, I would screw it all the way in, counting the turns to see where it was set, and then I would start by backing the srew out about 1-1/2 turns, start the engine and see what your vacuum reading is. If you're having trouble keeping it running, you can adjust the idle screw on the throttle stop to ease up the idle so it will stay running, and then you can adjust the idle mixture screw to where you have the highest vacuum reading, reset the idle to a normal 600-700 rpms. Piece of cake..

One other thing I would try before doing this, is while it's running, spray some carb cleaner around the base of the carb, if the engine idle increases while doing this you have vacuum leaks at the base of the carb, and will need to replace the gaskets.