Low Vacuum

[Jarrod]

Gents,
I have a 6.2 fitted to a Range Rover. The problem I have is the vacuum pump does not do it's thing all that well at low engine speed. At high speed not a worry all the vacuum in the world. Is this a normal characteristic ? Any suggestions I have already fitted a vacuum reserve tank which helps. The only theory I cold come up with is a partial blockage in the system that is overcome as the vacuum increases with engine speed.
Thanks
Jarrod

[gmctd]

Can be caused by leaks in system - hoses, fittings, etc.

Pump inlet\outlet one-way valves harden with age and heat. Symptom - low vacuum at lower engine rpm.

In the past, you could grind off outside rim of pod housing, replace valves, pop rivet housing halves back together with original diaphragm.
Don't know if valves are still available, now.

If all else checks ok - replace vacuum pod.

[A M A]

how would your truck run with a bad vac pump

[gmctd]

EGR\EFE not functional, cruise not functional, heater\ac system not functional.

[britannic]

Originally posted by A M A:
how would your truck run with a bad vac pump Trucks fitted with the TH400 that use a vacuum signal from the throttle position sensor, won't shift properly.