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#1 |
![]() Join Date: Feb 2011
Location: Vicksburg, MS
Posts: 135
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I've got an interesting one I think. A few weeks ago I started up my z to let the fluids get circulated and burn off some condensation. Cars been sitting a lot lately. I started the car as I always do. Turned the power on and let everything prime before starting the car. Usually the vacuum pump runs a few seconds like always, priming the system. Well, this time it came on and did not turn off. Even with the engine running, it ran continuously. The car had a little trouble starting, but nothing major. I chalk that up to it having been sitting a few weeks.
The engine didn't idle high or low. No sputters, nothing that was out of the ordinary. I didn't take if for a drive because I didn't have the time. Well, this weekend I had a little time to go mess with the car. This time everything behaved as it always has. Turn the power on, vacuum pump runs a few seconds, shuts off. I even turned the car on and off a couple times and the pump didn't even come on to re prime the system, and if it did, it was for a second or less. Car started fine and held a vacuum. What could have been the deal? I will say that when the pump was running continuously, it was a few weeks ago when the temperature dropped like a rock. May that have had something to do with it? I've never had any vacuum problems before. I know that they can pop up suddenly, but go away suddenly as well? Thanks guys
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[B][U]1991 No. 519[/U][/B] |
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#2 |
![]() ![]() Join Date: Jun 2005
Location: pittsburgh
Posts: 4,633
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Mines doing the same thing. I'm stumped
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It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B" |
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#3 |
![]() Join Date: Jun 2005
Location: CenCoast California
Posts: 899
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Have you guys leak tested your secondary vacuum system?
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Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878 |
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#4 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,697
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Guys,
When the weather turns cold, my tires will lose pressure. It may be a case of something shrinking faster than something else. Then everything stabilizes. As Hib suggested, I would do a quick vacuum test. Perhaps even the secondary vacuum solenoid may have been stuck and then freed up once warmed..
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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#5 |
![]() ![]() Join Date: Jun 2005
Location: pittsburgh
Posts: 4,633
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![]() I did. And it tests fine but sets a low vac code. It it did. Last time I drove it, ran fine.
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It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B" |
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#6 |
![]() Join Date: Jun 2005
Location: CenCoast California
Posts: 899
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"low vac code".
Code 56?
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Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878 |
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#7 |
![]() ![]() Join Date: Jun 2005
Location: pittsburgh
Posts: 4,633
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__________________
It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B" |
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#8 |
![]() Join Date: Aug 2013
Location: Kane Pa
Posts: 28
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there's a vacuum-electric switch that is probably sticking. Try tapping on a running vacuum pump when the engine is running.
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#9 |
![]() ![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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Third time was the charm on mine for that nonsense: Strike THREE! Now it NEVER comes on! (& You can guess why not!
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Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry |
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#10 |
![]() Join Date: Feb 2011
Location: Vicksburg, MS
Posts: 135
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It's been on the list...
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[B][U]1991 No. 519[/U][/B] |
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