Vacuum Gauge Installation problems

[UltraJosua]

Hey!

I've just received my new Vacuum Gauge. Went to search for where to plug it in. search a little more, scratched my head a few time, punch a hole here and there, cut a little, put in the T, wire everything back the way to normal.

Start the car, then I only see 4-5 psi on Idle... damn, Starts revving a little, goes down to 1-2 psi...

Searched a little more, find exactly what I cut up. Realise I messed up. Search for more information. Found my throttle body, look for a hose, nothing, find my MAP sensor, no hose there. ...

I'm in a bit of a fight here.
To worsen my situation, there is no haynes manual for my 2004 jeep wrangler...

This is a picture of my actual motor compartment.

Could someone help me to figure out which hose should be the one!

Thanks!

[SVOboy]

Does the line that goes to the brake booster get full manifold vacuum?

Good luck getting it up and running.

[Christ]

Any line that is coming from the intake manifold will do, as long as it's not valved or restricted in any way.

If you need a line specifically for the vacuum gauge, get a threaded barb, remove your throttle body, stick a vacuum nozzle in there, drill/thread a hole for the barb, while the vacuum is on, so you don't get any metal shavings in the engine. Screw the barb in, then plug the line onto it.

[Old Mechanic]

Use the manifold end of the booster hose. Bore a small hole right next to the fitting on the manifold so you can shorten the hose if you ever want to take it out.

Get one of those cone shaped adaptors that goes to many different size hoses for using the vacuum gauge.

Make the hole big enough to stick about 20% of the cone shaped adaptor in the hole in the brake booster hose. Shove the sucker in and if necessary use some adhesive to hold it in place.

Worked perfect in my Echo. The valve for the brake booster is in the booster itself.

regards
Mech

[vtec-e]

When i put a vac gauge in my civic i just teed it into the brake booster line. Then i ran some pneumatic hose through the firewall to my gauge. It worked great.
The revving you describe suggests an air leak in the intake pipework. Go through all of your connections to make sure they are tight and sealed. Also check your vac gauge. There is a tiny possibility that it is leaking. Take it out and apply a vacumn. Listen for hissing or just the sound of air moving. Should be quiet, otherwise the gauge is faulty.
I must also point out that if you do tee into the brake booster line, make sure your connections are solid and won't break. Although if you are paying attention to the gauge you'll spot vacumn problems quickly.

ollie

[Christ]

My Caravan will run w/ the booster line disconnected and not capped... it just closes the IACV. The only way it won't is if the influx of air occurs too quickly for the PCM to adjust, then it will either stutter or stall.

[UltraJosua]

Thanks everyone, The booster line was actually my next guess, So as soon as it stops raining outside, I'm going to fix it.

As for the revving, it was just me pushing the throttle on neutral. Testing the Vacuum to see if something would move. Sorry for the confusion

[Johnny Mullet]

I hooked the vacuum gauge up on my Metro using the brake booster line and it worked quite well. The closer you attach or "T" it to the engine, the more accurate the readings will be.

[UltraJosua]

As funny as it can be, It's probably the first place I can see people telling actually where they plugged their vacuum gauge. Every time they simply say , OH! I plugged it and it worked beautifuly for the first time. meh I'm no car mechanics I know...