The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support Rix Racing
Please Support ExtremePSI

No vacuum at P port at idle, but vacuum and boost while driving - what's up?

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Gremo87

Proven Member
128
2
Mar 14, 2013
Decatur, Illinois
So I've been working on a low vacuum issue, and I just read that the P port on the TB is supposed to have vacuum at idle - but mine doesn't. My boost gauge used to be hooked up there, and it would see vacuum and boost while driving, but nothing at idle. (I moved it to another source because of this)

I've read maaany people saying it should see vacuum at idle - including at least 1 "Wiseman."

I've read that it can be clogged, but if I can see vacuum and boost while driving, I wouldn't think that's the case....



Anyone know what the deal could be here? It might be completely unrelated to my low vacuum issue, but it just concerned me.

Edit to add: Just found this guy (http://chicago3s.proboards.com/thread/146/1g-mods-free) saying that the P port only sees vacuum on 90-92's....
 
Last edited:
the p port only sees pressure when the butterfly is open. the p is for pressure. so it'll only see any type of pressure after that. someone said the a port should read both. but most people just T into the vacuum line from fpr and intake manifold. people put the boost gauge and map sensors there
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top