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punx2400

95 legacy brighton wagon bucking around 2k

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I've been noticing this weird tick in my car's personality lately.  She likes to buck like crazy in 2nd, around 2k to 2250 RPM, and from about 1850 to 2250 in third, if I'm just puttin along.  like tailing traffic on 405, not moderate, even hard throttle.  just chillin.

I'm no pinball wizard, but I'm leaning towards either MAF malfunction or front cat clogged. rear is gutted already, due to misdiag for a failing fuel pump, TPS has been swapped with a scrapyard model of same MY range just to test, as well as the coilpack, which looks newer and actually has a part number versus the old one that looked like a Chinese Special.  


Your thoughts?

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is the car new to you? miles on car? tires all the same brand/model/size?

 

CEL on?

 

the whole car is jerking/bucking? does it maneuver OK in parking lots? will it turn a tight circle smoothly on dry pavement at idle or 1K rpm ?

 

any chance the car is OK when stone cold - then fails after warm-up?

Edited by 1 Lucky Texan

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No CEL, 260K, maneuvers just fine in tight spaces. All tires exact same, same tread % and everything. Clutch test checks out as well, however, the pilot bearing does squeal ever so gently when idling... If that helps.

Edited by punx2400

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Oh, and no, car isn't new to me. I've had it since late summer last year. This is a new development however. Been doing this for about 2 months.

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so, if you were at the problem speed and let of the accel. or push in clutch pedal - the car is smooth?

 

do you have the 2.2l engine? time since timing belt service?

Edited by 1 Lucky Texan

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as noted above...does it when still cold and warmed-up? Thinking CTS.

What about a loose vac line?

MAF can be cleaned, but they fail often enough to be suspect.

 

If it were a clogged CC, I'd 'think' you'd pop a 420 (UR in WA so whatcha expect? :-)   )

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Does it all the time. Put a "spacer" on the rear O2, so no codes. Not sure what you mean with the being in Washington comment...

 

 

Maybe engine/trans mounts overdue for changing?

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not sure about 95, 'most' 2.2s are not interference, still, you might confirm timing hasn't slipped a tooth or 2.

'90-'96 are NON-interference; everything newer is...including the '99+ Phase 2.

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I've been noticing this weird tick in my car's personality lately.  She likes to buck like crazy in 2nd, around 2k to 2250 RPM, and from about 1850 to 2250 in third, if I'm just puttin along.  like tailing traffic on 405, not moderate, even hard throttle.  just chillin.

 

...........I'm no pinball wizard, but I'm leaning towards either MAF malfunction or front cat clogged. rear is gutted already, due to misdiag for a failing fuel pump, 

 

Improper adjustment of the TPS's Idle switch circuit.

 

When you are cruising, light throttle, so light that it closes the contacts on the idle switch.  This triggers fuel cut for coasting/engine braking, becasue it thinks you are "off throttle".  You feel car slow, then hit a bit more gas which opens the contacts of the idle switch but also already your way into the % throttle open range.  This creates the bucking effect.

 

You need to test and make sure the idle switch circuit goes open at no more than a hair off throttle.  There is a spec for a feeler gauge to use.  Im guessing around .20mm.

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Could you elaborate on that? Not understanding where to check for .20 with a guage...

between throttle lever and stop screw.

 

Measure for closed contacts of the idle switch when full against screw.

 

then check that contacts are open when a .20mm feeler between the throttle and stop screw.

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At the same time, I read that someone tried it anyway, and had good results-----until the computer learned the throttle deadzone and the performance issue returned.

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Thanks gloyale, I'll try that next. So I changed out the CTS this morning. Man was that little bastard difficult to get to. All my air inlet hoses and harnesses are stiff as a board. After a drive test, it seems a little better. I'll address the TPS tomorrow if it's not snowing...

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Nope. Sat in traffic on the way home today, still bucks. Gotta be the TPS/MAF...

 

Furthermore, I don't know how CTS's work, but with the old one, the temp needle would NEVER get above the water line of the symbol on the temp guage. Today(this morning when it was cold out as well as on the way home when it was warmer out) the needle went all the way to the top of the thermometer symbol on the guage. I don't know if it's because of the air pocket that was probably created when I pulled the old sensor out and about a pint or more of coolant leaked out, or if this new sensor is just accurate. But if I'm cruising at 55-60,the needle reads normal. If I go 65-70, or lug the engine, the temp rides right around 70% of the needle's sweep range. Hmm. Hope it's not head gaskets that have been going that till now went undetected aside from oil leakage. No oil in the coolant or milky oil so..... Uuuugh

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indeed something still seems wrong if I understand your temp gauge description.

 

on both my cars, if the gauge were the left side of an analog clock, the hour hand indicates about 8:30

 

as shown here;

 

120625d1416601454-my-coolant-temperature

 

 

never seen my WRX go above 8:30, I HAVE seen the Outback get to ~10 in the desert; uphill grade, 3 people and luggage. 116*F outside.

 

no, I don't want to got to '11' !

Edited by 1 Lucky Texan

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Burp your cooling system.A  properly running subi should hold the exact same place on your gauge at all times when warmed up. Exception's for extreme temps are ok.  A new sending unit could read at a different location but it should remain rock solid !  Burp your system ,if its full maybe your thermostat is failing ? Electric fans working ?  

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indeed something still seems wrong if I understand your temp gauge description.

 

on both my cars, if the gauge were the left side of an analog clock, the hour hand indicates about 8:30

 

as shown here;

 

120625d1416601454-my-coolant-temperature

 

 

never seen my WRX go above 8:30, I HAVE seen the Outback get to ~10 in the desert; uphill grade, 3 people and luggage. 116*F outside.

 

no, I don't want to got to '11' !

Mine's a little different.

https://imgur.com/VtYQyxp

This isn't my car, I got the photo off google, but exactly the same.  On THIS guage, my needle will hit the top of the thermometer.

 

Burp your cooling system.A  properly running subi should hold the exact same place on your gauge at all times when warmed up. Exception's for extreme temps are ok.  A new sending unit could read at a different location but it should remain rock solid !  Burp your system ,if its full maybe your thermostat is failing ? Electric fans working ?  

Yes fans are working, but I think you may be right about the T-stat.  How do I go about burping the system?  I bought a gallon of coolant, expecting to be able to top off the radiator and call it a day.  I went to pop the cap off, which I might add was literally cold, whereas the upper hose was HOT.  Reservoir was half full as well.....huh.

Edited by punx2400

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In other news, I forgot to tell you guys about this little discovery I made the other day.....
Apparently, the PO bypassed the TB where THESE hoses connect.

https://imgur.com/AF1ED9V

Just one, what looks like a 3/8" fuel hose running from a nipple at mid passenger side, then under TB, and over to another nipple on the driver's side. 

 

What is the purpose of doing that, and what harm can/will come of it? 

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only use an original subaru thermostat on it. The parts house ones are not worth your time.

Dammit!  I already have one waiting for a not so rainy day to put it, the timing components and W/P in.  Some fancy shmancy MotoRad failsafe model.

Edited by punx2400

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I can only guess that one of the original hoses ruptured ... and he  didn't have replacement but he did have spare fuel line. Nothing good can come from doing this.  

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