I've searched many time now and come up with almost nothing on raising the vacuum. It sits pretty damn low at idle (15inHg) , and it worries me becasue I feel like I am not gettin all that much power off my old/new TII coil and mallory 6a cd ignition system, even though the car seems to be ideling just fine...a bit smoother if anything with the new parts but it doesn't feel llike its pullign any harder...slower if anything...and my last leading coil as fried. THE Mallory is workign properly becasue the light is on when the car is running meanning it is gettin a proper trigger signal. So whats a way for me to raise my vacuum....


I know I shoudl recheack all my vacuum hoses
check all my gaskets
check all the intake pipe connectoins
check my UIM and LIM bolts...
check if the turbo is properly tightened onto the car.
check housing compression?

THis is my set up.

DP, CB
pullies
no A/C
no air pump
Denso high feed fuel pump
new all trailing plugs
new magnacor wires
TII leading coil and mallory 6a CD
new vacuum hose job
By passed the solenoids at the front of the UIM.

 

If your concerned about the engine, then get a compression test . Vacuum around 15 inHg could be from worn seals or from a number of factors (like you have listed, or a ported engine). If the car is driving fine and you do not want to deal with the thought of a rebuild - then just enjoy it until it becomes an issue .

never mind.... just saw that this was a double thread.

 

I get about 15inHg vaccuum in my car. Idle is great, motor has about 55k miles, ran a compression test which came out decent but dont remember the numbers at the moment. I have had the car since that motor was new and vaccuum has always been the same. I would say not to worry about it unless something happened and it suddenly lost vaccuum.

 

Vacuum at idle is a not very comparable from car to car. It changes with idle RPM, altitude, boost/vacuum gauges aren't always very accurate, etc. If I hopped in a car and saw 15 inHg, I would not be alarmed in any way.

However, if your car always pulls 18 inHg then only pulls 15 inHg after some event, I would be concerned.

So, how much vacuum did your car pull before at the same idle RPM?

-Max

 

I made a reply yesterday, but the forum ate it...grrr...

Anyhow, one cause for concern with me is the missing air pump. The stock ECU (which I'm assuming you're running or a chipped ECU) doesn't like the air pump not running. Idle mixture is set by feedback from the O2 sensor, as is part throttle and cruise. The ECU knows when the air pump is injecting air in the manifold, and compensates the reading for the extra oxygen that the air pump is putting in the system. With no air pump, it is still trying to compensate the mixture, and you end up with either too rich or too lean.

I accidentally blew my air pump fuse a while back, and the car ran like crap without it. Idle was rough, throttle tip-in sucked, etc. I also lost some idle vacuum.

Dunno if it's possible to put the air pump on to test the effect - you may be too far gone to do that easily .

Dale