Vacuum Gauge Install; Engine Line Tap Location

[user removed]

Not sure about true vacuum in the PCV system since it is basically a controlled vacuum leak, purging crankcase vapors to the intake manifold. I don't think the VX even has a pcv valve, just an orfice (from memory, could be wrong).

Booster line is absolutely manifold vacuum.

regards
Mech

[DOFZO]

Originally Posted by Cobb

The thing circled in yellow is the booster. You want to tap a hose from the intake manifold that is behind the yellow line on the image. Anything between the air filter and throttle plates wont have vacuum unless the throttle is open and the air filter is really dirty.

Originally Posted by Cobb

How about hose 19? Looks like the PCV I spoke of in another thread.

Thanks for the help! I'm avoiding the PCV valve hose because of what Jim posted earlier.





ZO.

[DOFZO]

Originally Posted by Old Mechanic

Big black metal "tank" behind the brake master cylinder is the booster. The hose runs from that to the top of the intake mainfold and the check valve is about midway on that fairly large hose (maybe an inch outside diameter). Make a small hole in that hose between the manifold and the check valve, close to the check valve so you could just shorten the hose and reattach it without any problem.

Push your metal vacuum connector in the hose until it is tight then run a hose to your gauge through one of the existing openings in the firewall.

regards
Mech

BINGO! Thanks!! I'm going to pick up a spare hose from the junkyard to actually tap into so I don't have any worries about where I splice the hose.

Just to confirm. Red circle is the check valve. Red arrow is the hose to tap.




Hose - #8. Check valve - #7.







ZO.

[DOFZO]

Originally Posted by Old Mechanic

Not sure about true vacuum in the PCV system since it is basically a controlled vacuum leak, purging crankcase vapors to the intake manifold. I don't think the VX even has a pcv valve, just an orfice (from memory, could be wrong).

Booster line is absolutely manifold vacuum.

regards
Mech

During a recent tune up I changed the PCV valve. Here is what I found; the original valve is on the top. No guts, no valve. The OEM Honda one is on the bottom and is shown as the correct part number for my VIN both online and at the dealership.




I bought the car with 224K miles on the odometer and as far as I know the PCV valve was original. I did put in a OEM Honda PCV valve, but I saved the "old" one just in case.





ZO.

[user removed]

You got it. I would just punch a hole near the check valve, then you could just cut an inch off an reconnect it if you wanted to remove the gauge. Get a piece of tubing or a tapered fitting and stick it in the hole (maybe with a little adhesive caulk), run the hose for the fitting to your gauge, use an existing access hole in the firewall (repeating myself).

regards
Mech

[user removed]

If the part you get does not look like the one you took off, then make sure you can reverse that part replacement. I prefer original equipment, unless the difference in cost is exorbitant. I did not like using my customers as guinea pigs to experiment with cheap parts, when I warrantied everything for a year and unlimited mileage. These days with chinese imports the quality issue is a magnitude worse than it was in 1999.

Picture below, just drill a small in the hose and stick one end in the hose (use some adhesive sealer if you want),

regards
Mech

[DOFZO]

Originally Posted by Old Mechanic

You got it. I would just punch a hole near the check valve, then you could just cut an inch off an reconnect it if you wanted to remove the gauge. Get a piece of tubing or a tapered fitting and stick it in the hole (maybe with a little adhesive caulk), run the hose for the fitting to your gauge, use an existing access hole in the firewall (repeating myself).

regards
Mech

Thanks again! I'll post pics up when I have it installed. Maybe someone can use this tread as well.

Originally Posted by Old Mechanic

If the part you get does not look like the one you took off, then make sure you can reverse that part replacement. I prefer original equipment, unless the difference in cost is exorbitant. I did not like using my customers as guinea pigs to experiment with cheap parts, when I warrantied everything for a year and unlimited mileage. These days with chinese imports the quality issue is a magnitude worse than it was in 1999.

regards
Mech

If this is about the hose, there's a '94 Civic sitting in the junkyard that I'll source the hose from.

It it's about the PCV valve, the one I installed is OEM Honda, but you're not the first person I've heard say the VX didn't really have a PCV valve so I saved the original one just in case I notice a difference with respect to the engine/mpg/idling, etc. The OEM Honda (part #17130-PM6-003) does have a valve in it.

I appreciate all your help! I'm excited to get the gauge installed, to "see" the health of my engine and to improve my "pedal control"!





ZO.

[DOFZO]

Installed! Idles at 16 in. hg.! Steady!

Although, I'm not quite finished yet. The readings were with the gauge hooked up resting in my hand. Once I had the gauge completely installed in the pod I was only getting 14 in. hg. It didn't make any sense so I pulled the gauge from the pod and found I had crimped the hose between the pod and the a-pillar trim. I need to enlarge the hole in the pillar trim and pull the hose snugly as I install the gauge.

Posted below are a few pics from the install. Thanks to all those who helped in this thread!

Brake booster line with the HELP tee installed.


Pulled an existing firewall plug and pushed a hole through to the interior. The line comes in just to the left and above the clutch cylinder.


Firewall plug drilled out to fit the vacuum hose and retain the OEM plug!


Gauge and pod installed! I sourced an additional A-pillar trim piece for the install. I primed and then painted the lower half of the pillar black then clear coated before installing the pod.

[user removed]

Very nice job. The windshield pillar pod mount is very nice and could pass for original.

regards
Mech

[DOFZO]

Originally Posted by Old Mechanic

Very nice job. The windshield pillar pod mount is very nice and could pass for original.

regards
Mech

Thanks. The pod is from Auto Meter, same as the gauge. It's a great fit with the interior trim. A must for me!

I really appreciate your help with installing the gauge, especially locating the brake booster line!





ZO.