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#1
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Random, violent hesitations
I have a 1992. While accelerating in any gear, any rpm, I'll sometimes get a really bad hesitation as if the engine is locking up or I'm slamming on the brakes. I just changed the plugs and all the coil packs look fine. I just sea foamed, replaced the air and fuel filters, replaced the maf, and it still hesitates. It used to have an automatic transmission but I did a 5-speed swap (2004 Impreza), still hesitates so I've ruled out the tranny.
Anybody have some ideas? There is a cel on but it's for some egr stuff. My car also loses horsepower at higher rpms, falls flat on its face.. that's probably egr-related but I'm more worried about the hesitations than power right now.
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Brian |
#2
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If you are feeling froggy, try changing out the 02 sensors. We had a car do that at the pumpkin carve meet. Changed em out and violah! It is the same issue we had with Dan's 94 pearly too.
Tom |
#3
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How does the O2 sensor do this? So if you were to remove the O2 sensor, would you experience this violent hesitation?
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Kevin Thomas 1997 2.2ltr Subaru Impreza Outback Sport Wagon (AWD/Auto) 13.03@100mph 1989 2.7ltr Subaru XT6 (AWD/Auto) 15.912@85.93mph 1996 3.3ltr SVX (AWD/Auto) 15.070@91.38mph ***R.I.P*** 2010 RAV4 AWD Sport (13.717 @ 99.19mph ) 2015 Honda Fit LX CVT (15.2 @ 90mph) |
#4
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I replaced one of them with a new one, waiting for napa to be restocked.
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Brian |
#5
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I thought if you remove the O2s it just runs in closed loop? Or was it open? One of the two.
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"That which can be asserted without evidence can be dismissed without evidence." '92 Dark Teal SVX LS-L, >146,000m 3 pedals, 5 speeds., restoration underway. 2012 Honda Insight, slow but cute. |
#6
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not sure either. it sure was strange to me. This is a real problem for people experiencing it, it def is not easy to diagnose either
Tom |
#7
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apparently, wacked out O2 sensors on the EG33 can cause extremely rich mixtures to the point of raw gas puddling in the exhaust pipes (I think OT was the first person to come across this little joy).
If replacing both O2 sensors doesn't clear up the problem, I'd look at the FPR and the ECU. -Bill
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Retired NASA Rocket Scientist Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023 Center Network Member #989 '92 Fully caged, 5 speed, waiting for its fully built EG33 '92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension '92(?) Laguna, 6 spd and other stuff (still at OT's place) My Locker |
#8
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or extreme lean conditions. This would cause erratic timing to be pull and thus the hesitation esp at highway cruising
Tom |
#9
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What about MAF? Remember our convo the other night Tom. We troubleshot my issue down to the faulty Z32 MAF.
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1992 SVX LS-L: Now TomStock Stage 3... 6MT, R180 Rear, Tomstock Short Shifter and hard rubber mount, Group N Motor and Tranny Mount, Stage 2V6 Chip, Z32 MAF, Stage 3 CAI, Stebro, Intake Cams, 17" STi BBS Powder Coated Black, Bridgestone Potenza RE070, and Koni inserts w/Mychailo's Springs! Sand Diego SCCA Solo 2 #308 RIP 84 VW Scirocco 02 WRX 88 XT6(regret the day I left her behind) socaleuro.com They like the flat 6... Check My New Homepage.. |
#10
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He said he replaced the MAF in the Original Post.
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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 |
#11
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I replaced the MAF in his car with no results... This is something completely different.... What the hell are you doing posting here, we haven't heard from you for a year
Tom |
#12
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If it's any consolation to anyone, my car also has this problem.
It did when it was driveable anyway.
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"That which can be asserted without evidence can be dismissed without evidence." '92 Dark Teal SVX LS-L, >146,000m 3 pedals, 5 speeds., restoration underway. 2012 Honda Insight, slow but cute. |
#13
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I'm getting crap gas mileage (~230 miles a tank) so I'd guess it's going rich..
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Brian |
#14
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Quote:
-Bill
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Retired NASA Rocket Scientist Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023 Center Network Member #989 '92 Fully caged, 5 speed, waiting for its fully built EG33 '92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension '92(?) Laguna, 6 spd and other stuff (still at OT's place) My Locker |
#15
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cam position sensor!
Quote:
My symptoms (while accelerating) - fell flat on its face at higher RPM's - this happened for about a year before the next two symptoms which occured within a two week period. No CEL of any kind. - violent hesitation - the motor would totally lose power for second and then gain it back - almost like a bad fusible link that shorting against the frame. I'm pretty sure this led to one of my motor mounts tearing in two. - bad miss (ultimately blew out the main converter) - this got progressively bad on my way home from work one day that by the end of my commute, the car wouldn't rev past 1800 RPM in any gear (with the gas pedal floored). Finally got a CEL, and it indicaated the cam position sensor. Don't wait until it gets this bad - change it now. You can get them new from Oreilley's for $150 or so or get one used. My fix - $40 and one used cam position sensor from Budfreak (before his demise) later and the problem went away. Took me ten minutes to change it out. I removed the battery to make it a bit easier. Hope this helps. |
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