#84137, "low vacuum at idle, give me some insight"
last night on the way home from work my car started running kinda rough at idle, lower than normal vaccuum is the first thing i noticed. no cel's, no obvious vacuum leaks i checked them all and dont hear any hissing or anything. i noticed the problems when i was coming down fast from 100mph through a tunnel and braked hard. (increasing vac and possibly increasing the leak?)
one thing though, my cyl 2 injector has a lot of oil and dirt on the outside looking from the top over the valve cover, the rest are clean...i dont get how or why this one is dirty.
my idle doesnt go up or anything it stays at about 850-1000, i changed out the plugs thinking one might have fouled since im so rich and it only helped about 2hg on my boost gauge. i dont think its a vaccum leak, i did the keydance and got CEL 31 but my logger doesnt show any codes when i run it through the datalink port. i capped off the evap at the tb to see if it was the evap line possible vac leak but still no dice.
help me out here, im kinda lost. i think its just a vacuum leak but it was dark last night and i didnt have much time to try and figure it out. i dont hear any hissing like a vacuum leak typically does.
one question though, you think it might be cyl 2's injector o-ring? like i said that injector was unusually dirty for some reason on the outside compared to the rest of them
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96 Black ESi 91 Red TSI AWD (RIP) 02 WRX
"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"
Aerospace Certified TIG welder for Precision Castparts in Portland, OR.
#84140, "RE: low vacuum at idle, give me some insight" In response to Reply # 1
Originally posted by grain if the inj-oring isnt seated right, it will leak. and if you say its dirty. then id take that as an answer.
yea i know i just love to answer my own questions but i was confused on how the injector could even get dirty like that...dirt flying out of the intake manifold past the o ring?
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96 Black ESi 91 Red TSI AWD (RIP) 02 WRX
"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"
Aerospace Certified TIG welder for Precision Castparts in Portland, OR.
#84143, "RE: low vacuum at idle, give me some insight" In response to Reply # 3
Originally posted by thedawg Gasoline has oil added to it. If you're leaking fuel onto the injector, dirt will eventually stick to it. As far as the rough idle, low vacuum, do a compression test & boost leak test.
thanks dan, my money is definately on a leaking injector o-ring now, i'll do a compression test but im 99.9% sure thats fine
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96 Black ESi 91 Red TSI AWD (RIP) 02 WRX
"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"
Aerospace Certified TIG welder for Precision Castparts in Portland, OR.
#84159, "RE: low vacuum at idle, give me some insight" In response to Reply # 5
Originally posted by turbo8u got this from exile's site... ..."Check for stains around the injectors, seeing stains or spots can be a sign of a leaky injector O ring."... i think thats my culprit
well.....whats the verdict. did ya check it out.?
I eat emo kids for breakfast
1995 Eagle Talon (SOLD) 72' SuperBeetle 72' Standard Beetle 56' Deluxe Beetle
#84161, "RE: low vacuum at idle, give me some insight" In response to Reply # 6
Originally posted by Blizare
Originally posted by turbo8u got this from exile's site... ..."Check for stains around the injectors, seeing stains or spots can be a sign of a leaky injector O ring."... i think thats my culprit
well.....whats the verdict. did ya check it out.?
no i had to work today so i got a ride and my talon is sleepin at home for the day. i'll check it out tomorrow
bump, slick where you at?
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96 Black ESi 91 Red TSI AWD (RIP) 02 WRX
"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"
Aerospace Certified TIG welder for Precision Castparts in Portland, OR.
#84163, "RE: low vacuum at idle, give me some insight" In response to Reply # 7
Yo whaddup my homie...
I'd start with the injector o-ring. If it still happens... try unplugging the ecu for 5 minutes. Sometimes my IAC will get whacked out, and the ecu needs reset to get it back...
Also, check the PCV valve... if that's fubared, you can have lower vac... but the IAC might be able to compensate enough with the idle speed...
#86015, "RE: low vacuum at idle, give me some insight, again" In response to Reply # 10 Feb-15-05 05:18 AM by turbo8u
ok i replaced my injector o rings because those seemed like they needed it and also replaced a lot of vac lines, car runs perfect when its warm with no problems.
however, the car idles really bad ONLY when its cold and just started. idles between -10 and 0 and choppy as a mother fucker. if i rev it a lot and warm it up a bit it idles perfect again pulling strong vaccum...
any ideas?
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96 Black ESi 91 Red TSI AWD (RIP) 02 WRX
"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"
Aerospace Certified TIG welder for Precision Castparts in Portland, OR.
#86016, "RE: low vacuum at idle, give me some insight" In response to Reply # 10
Originally posted by turbo8u im also going to spray some crab cleaner on my vac lines and see if something turns up
Your car gets around, huh? Crab cleaner. Heh. Sorry had to comment on that. Anyway... Nothing in my motor stays clean, and my injectors are always dirty. I don't think that is your problem, but you never know. After you give that a look, or even before that, I would check your compression, hope thats not the problem tho!
#86017, "RE: low vacuum at idle, give me some insight" In response to Reply # 13
compression is good, like i said the motor runs fine but not when its freshly started after a night of staying cold.
now its my understanding the EGR is used to warm up the motor faster? if the EGR is fucked up, it would cause a shitty idle like this wouldnt it? the IAC and the EGR work together, especially during warm-up...
tonight when i leave work im going to disconnect the EGR and see how it runs when started up...
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96 Black ESi 91 Red TSI AWD (RIP) 02 WRX
"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"
Aerospace Certified TIG welder for Precision Castparts in Portland, OR.
#86034, "RE: low vacuum at idle, give me some insight" In response to Reply # 14
Well I've noticed when resetting the ECU(when you have the EGR totally disconnected and NON functional), the ECU does the EGR flow test. It closes the IAC and tries to get the air from the EGR valve. Since the EGR isn't working, the motor will run rough and stumble for a minute, then get back to normal. This happens on my car whenever I reset the ECU, OR erase the CEL with my logger. It only does it once though, after the CEL comes on and not resetting.
One more thing to look into, is the EVAP system. If you have a larger leak somewhere, it may cause lower vac. The ECU generally opens the EVAP solenoid and purges the gas tank at warm up, and occasionaly during normal driving. An easy way to bypass the EVAP system, is to cap off the vac nipple directly on top the throttle body. It's the line that has that short 90 degree rubber vac line, that goes to a plastic hard line by the firewall, and around to the passenger side, right infront of the timing belt area.
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#86035, "RE: low vacuum at idle, give me some insight" In response to Reply # 15 Feb-15-05 11:55 AM by turbo8u
yea i scouted around for a vaccum leak but didnt find anything, also replaced a ton of vac lines. (not the evap or boost gauge though) i figured if it was a vaccum leak the car wouldnt run right even when it was warm, the boost gauge would let me know.
you know, i think you're on the ball though with the motor trying to get the idle air from the EGR at startup and not the IAC, i think thats why when i rev it a bunch it starts to idle strong again. no CEL though...but i have a 96 and i dont know if it even DOES a flow test...
any problems with disconnecting the evap? besides a 31 code or something?
thanks matt
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96 Black ESi 91 Red TSI AWD (RIP) 02 WRX
"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"
Aerospace Certified TIG welder for Precision Castparts in Portland, OR.
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