Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved!

Topic: Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved! (Read 2375 times) previous topic - next topic

Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved!

Reply #15 – February 14, 2008, 05:17:21 PM

Quote

You went like this [motions two flat hands crossing in a "safe" action]

I went like this [waves flat hand up and down in a chopping motion]

LOLOLOLOL

I am SOOOO using that one!

Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved!

Reply #16 – February 14, 2008, 10:43:54 PM

Also i want you to check something else.
When you get your vac guage, ,,,,

hook the vac guage to the FPR line and FP tester up to the shrader valve
start motor
Jot down your vac and fuel psi at idle and at 4krpm

shut down
reconnect the FPR vac line
disconnect FP tester

Hook the vac guage to the vac distribution block and FP tester to the shrader valve
start motor
Jot down your vac and fuel psi at idle and 4krpm.

If you see a vac difference at the distribution block, something in between there and the FPR is sucking closed, clogged or partially working.

Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved!

Reply #17 – February 14, 2008, 10:50:24 PM

Good way to pinpoint. Thanks!

Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved!

Reply #18 – February 14, 2008, 11:16:44 PM

you mentioned earlier about driving with a vac guage hooked up. The shop manual called out to test drive the car with a FP tester hooked up and the guage secured to the windshield to simulate a load to observe fuel presure.

having said that, you typical FP tester does not come with an extention hose so i had to hand make my own FP tester rig with a long hose and a 100psi water guage. I watched my FP go from 40psi at idle and as i stomped the gas and the r's increased just to when 2nd was ready to kick, my FP was a low as 22. Thats back when i went with a 1990 SC 3.8L pump. That cured my power issues,, not to say a 3.8 had any but it was a night and day improvement.

just shootin breeze cause doing that vac guage on the motor while driving can be done easy enough. Im sure you could use the vac line up near the pedals that comes from the vac dist block as a source to hook up your vac tester.

Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved!

Reply #19 – February 15, 2008, 11:43:45 AM

OK, vacumm guage hooked up.....
12 inches @ idle in park -- 900 RPM
21 inches 3000 RPM in park :eek:
6 inches in drive @ 1600 RPM with foot on brake car not moving......
Time for a drive.

Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved!

Reply #20 – February 15, 2008, 04:55:16 PM

Quote from: V8Demon;204372

OK, vacumm guage hooked up.....
12 inches @ idle in park -- 900 RPM
21 inches 3000 RPM in park :eek:
6 inches in drive @ 1600 RPM with foot on brake car not moving......
Time for a drive.

If it is inches of mercury, the difference between park and 3000 RPM is 4.5psi in manifold pressure which would indeed change your rail pressure by 4.5-5psi between idle and 4000 RPM.

Everything sounds like it's working properly.

Vacuum increase at part throttle??!! Apparently It's OK in park.... Solved!

Reply #21 – February 15, 2008, 07:15:52 PM

A stomp on the go pedal creates havoc at the stop signs and the vacuum guage to pin @ 0.....All is well:evilgrin:

Chalk this one up to paranoia:toilet:

Thank you all for your input & help;)