adrial

Your decel vacum is similar to what I get and have gotten for years, idle vacum is low which to me indicates you should take a look at your idle system...

Netrunner09

Thanks Adrial, I was just thinking, could the idle rpm have an effect on idle vacuum. For instance, my idle is set at about 1000 rpm. Should I lower it down, or would that make no difference?

Chas

your idle vacuum can also have a lot to do with the work, or how easily, your engine runs at idle. For instance, if you have your a/c compressor running, your vacuum will be a little lower because your engine is meeting more resistance

MitchB

This may be a long shot, but -
Vac Gauge error? Possibly tiny leak in the vac line to the gauge? Sounds like the system is tight...

Sunroof. Cruise Cont. delete, tan Sport Seats - that's sweet. Welcome.

painkiller

Hey Joe, this may be a longshot, but did you zip-tie the hoses onto all the fittings? It would be more of an issue on boost but may be something to try if you didnt tie them. Also going with what Mitch suggested, what brand gauge are you using? If its an autometer it may be off a little bit. There was a thread a while back and a lot of guys had gauges that read either slight pressure or vac when the car was not running. If you re-used any of the rubber "hook" connectors you may want to double check them.

How did you connect to the vac canister, the interior vac fittings and the gauge?

John

theedge

Theres also the throttle body seals. Bruce Arnn made a kit to replace all those, Paragon carries it now as well.

brad-cam

What impact does the compression health of the motor have on idle vacuum ? For example, if a new motor runs 150 psi compression, and a worn one runs 130 psi, would the idle vacuum on the worn one have lower idle vacuum, assuming both engines had good sealed vacuum systems?

What about if one cylinder is weak on compression and the other 3 are strong ?

Netrunner09

Hey guys,

Boost gauge is a VDO. TB seals have been replaced. Idle vacuum is with a/c off. Boost gauge is hooked up off a t fitting on the KLR line. Will run a comp. test and check timing hopefully tommorow. Will update,
many thanks again, hopefully my rennlist membership status will update soon, I'm envious of the nice red under your names

Joe

Doyle623

Hello, I recently put a boost gauge on my turbo and all I am reading is boost and no vacuum.....where do I splice in my boost gauge line in order for it to show this.

hosrom_951

Do you have a boost gauge or a boost/vacuum gauge?

Boost gauges start at 0 and go on to 25-30psi, boost/vacuum gauges start from 30Hg till 20-30psi.

This is a boost gauge:



This is a boost/vacuum gauge:

Doyle623

It is a boost/vacuum gauge.

hosrom_951

motoxxxdeamon: Where did you connect the gauge? it should read vacuum regarless of where you hook it up.

Doyle623

I connected it to the line that goes from my intercooler pipe to the wastegate. I also have a manual boost controller instead of the diverter valve.

hosrom_951

Connect it to any other vacuum source, preferribly as close as you can to the intake manifold.