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#16
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-Jason (8/23/07-Present) 1995 Subaru SVX LSi (197k) Polo Green (#1102) 03/95 Mods: DDM Tuning 4500k 35w Low Beam HID, 100w H3 Bulbs, Extra Ground Cables, 15 minute $12.96 mod, svxfiles designed transmission mount (), sporting a "new" tail light bar, silver BBS rims, custom power steering cooler (one that doesn't dump ATF constantly), new negative lead cable, no more third or fourth gear (1977-Present) 1977 Chevrolet Corvette (81k) Silver (12/01/2011-Present) 2005 Subaru Outback 2.5i Limited 5MT (97k) I have a bad feeling about this. -Obi Wan Kenobi |
#17
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A dirty or faulty TPS will also cause slight surging. People usually don't notice until they use the cruise because no one keeps the pedal steady enough to notice it.
Doug
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1992 LS Touring (6/91) - Currently undergoing a five speed swap Black over Claret with spoiler; 235,000 miles; Mods: 2002 Legacy 5 speed, ACT Pressure Plate, Excedy Clutch, Short Throw Shifter, Aussie Powerchip 1992 LS Touring (6/91) Black over Claret with 2.5" setback spoiler; 202,000 miles; Mods: B&M Cooler 1994 LSi (4/93) Bordeaux Pearl; 198,000 miles; Mods: Weight reduction. 1969 Mustang GT Convertible 1970 Mustang Convertible 2000 Ford Excursion Sola lingua bona est lingua mortua. My Locker |
#18
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More to do with the gearing.
This surging has more to do with the gearing that the car has. Mine has standard gearing, but if it is in third, it will surge.
The way it works is, the Cruise vacuum motor pumps vacuum to the throttle diaphragm to open the throttle, the engine speed increases, the Cruise Comp. looks at the road speed to check if it is at the specified range, if ok, it holds it. If not it will adjust the vacuum to achive the specified range. All this is timebased, the set and checking intervials is fixed, to suit the 'rate of change' that the car will respond to the vacuum change, hence the gearing the car has. If the gearing is lower, the 'rate of change' will be quicker, than the timebase setting, so the speed rises faster than the vacuum setting, the Cruise sees this, so it reduces the vacuum, which drops faster, so it goes back and forwards, causing the surging. The fix for this is to reduce the engines reaction speed, so that it is more in line with the timebased setting, by restricting the vacuum line to the diaphragm. The type of clamp used on air lines used on fish tanks, or medical line equipment, can be used on the vacuum line, to adjust the flow to remove the surging. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#19
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LOL, now that's a technical fix...I love it. Off to the pet store I go! Thanks mate. Ali
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If it ain't broken it, doesn't have enough features!!! '92 SVX LSL '03 4Runner '96 FZJ80 Landcruiser '90 Mercedes 300E |
#20
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I fixed about 95% of the surging during cruise control. Turns out that at some point during maintenance to my car, the cruise control cable and the throttle cable got switched on the throttle body. The cam on the throttle body for the cruise control system is larger and this appears to be affecting how the cruise control works. Could be that the larger cam causes less change in the throttle position, or maybe the cruise control system is sensitive to the pulling force required to open the throttle with the larger cam. Anyhow, its nice to have a non-surging cruise control again.
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Mychailo :: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ :: 1995 Laguna Blue SVX L AWD 5MT (sold) Visit my locker SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads. |
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