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#1 |
Join Date: Nov 2006
Location: Las Vegas, Nevada
Posts: 137
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After all of my under plenum repairs ext. I just got back from an after rush hour highway drive and I go to Full Power and my secondaries don't engage at all.
I feel a slight hesitation and then a check engine light, as soon as I go back to normal light goes out and car runs better than ever, I looked at the obvious plenum tube routing and I think its something else I probably knocked something loose. Any quick checks outside of the plenum? Thanks "The beat goes on" ![]()
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[SIGPIC][/SIGPIC] |
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#2 |
![]() ![]() Join Date: Jun 2005
Location: pittsburgh
Posts: 4,633
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it's a vacuum leak
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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 2010
Location: back in lone pine
Posts: 591
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do you have a scan tool .?is it code 61? when you just turn the key to on what does the vacume pump do ??
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#4 |
![]() ![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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Marc Haibeck wrote a great article. "Verifying Secondary Actuator Operation with the Plenum in Place", available on his web page.
Below is a schematic of the vacuum circuit for the secondaries and HVAC: ![]() Marc's article goes into detail, but it doesn't mention the possibility of the accordion snorkel tube between the air cleaner and the air horn collapsing; which it may well be doing at WOT IF either you don't have a Semco tube, or the wire hoops that Marc provides to support the tube, or a sleeve inserted inside of the tube to support it (and also smooth the air flow!). Overview: The vacuum pump provides initial vacuum to the vacuum reservoir, but mainly provides vacuum for the secondaries under extended WOT periods. Once the engine is running, the plenum provides all necessary vacuum to maintain the actuator reservoir, during normal driving. Upon snapping the throttle open, it is the secondary port throttle valve solenoid (#4 on the schematic) that opens and the reservoir provides the initial vacuum to pull the throttle plates open. Then if plenum vacuum is too low to hold the secondaries open, the vacuum pump will kick on and sustain the actuators. So, IF the vacuum pump does shut off (doesn't run continuously) then the system integrity - up to the solenoid - is good enough. (Refer to Marc's article for further troubleshooting of the actuators, etc.) If the pump does not shut off, then a there is a leak or the plenum check valve is bad, or the pump is not working. Disconnecting the line at the rubber connector as the vacuum line goes under the plenum and holding your thumb over the vacuum pump line should result in the pump shutting off in a second or two. If not, then the pump may be bad, or there is a leak somewhere. OR you could just take all the secondary crapola out and be done with it and it's problems forever...but that is another topic. Gotta run, but this should give you a place to start. Be back later to see how ya get along. P.
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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 Last edited by Paul Workman; 02-08-2011 at 08:23 AM. |
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#5 |
Join Date: Jun 2009
Location: I live at Devens, one run at a time
Posts: 455
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Every time (so far - knock on wood!) when I've had secondary problems it's been the cars way of telling me that the battery connection has loosened. Here's hoping that's your issue, the symptoms have always been just as you described.
Good luck, - Jeff
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[I]91 ZR-1 #1840, autocrossing in SCCA BSP. FIC S/S's DRM chip/Watson/Borla/lid/LW batt&headlights, springs, shocks, pads & lines, quick rack & Turn One, camber brace, 32/22mm sways, A/C halfway deleted 17x11 & 12 CCW's, 315 & 335 Hoosier A6s [/I] |
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