Vacuum Gauge Readings

[woodjeep]

I just installed a vacuum gauge today. Idle hot reading is 16 and rock steady. I haven't taken it out for a run yet. Where can I find a chart that gives readings and their meaning..Thanks This is still stock 4.0, 1992. I want to get a good database so when I put the stroker in I will have something to compare it to. I now have vacuum and am reading my O2 sensor on a voltmeter

[amcinstaller]

16-24 should be fine vaccuum for an engine at idle. expect it to drop dramaticly upon throttle.

[03GC]

My engine (KB944,Bullet 211/217 duration at .050) has a steady 16 in at 750rpm.
Paul

[IH 392]

The stock 4.0 in my '97 TJ is only pulling 12" at idle, according to the scan tool and TWO map sensors, never bothered to put a real gauge on it.

[gradon]

16-18" is normal for idle.

[stroked'73]

Any Haynes or Chilton manual will have a section usually in the tune-up section on what different vacuum readings mean. Also, a search on google or such will give you plenty of good links.

[woodjeep]

I finally got to drive into work thismorning. At around 65 mph in OD/ not quite 2000rpm/ 31 Rovo's and 3.55 gears I seem to run between 7-12 inches. It runs about 10-12 on level ground and drops down a little to about 7 when it needs to pick up a little . The smallest touch of the throttle will drop it down close to 0 for a few seconds then it comes back up to the 7's. If I'm cruising and turn off the CC or totally take my foot off the gas it goes to 20 when the throttle plate goes closed. Based upon this it seems that the Fuel press regulator will be in HIGH mode for most of my commute. Does anyone know where the exact shift point from 31 to 39 is. When there is less traffic I will try to play with it in 3 instead of OD

[woodjeep]

I ran it in 3 on the way into work today. 65mph-2500rpm. It mostly stays around 12-13 compared to 7-10 at 2000 in OD. Don't know which is better. I think I will do a tankful in 3 just to see what the mileage works out to be.