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#1
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'92 SVX misfire dealer lost
Fellers,
Took our '92 SVX with 165k to the dealer for an intermittent check engine light and the engine rough idle. The engine codes say the rear O2 sensor which doesn't exist. Anyone have any suggestions? thanks tdog |
#2
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Best is to check the code yourself.
Check the SVXipedia on http://svx-iw.com/ for how to check the codes.
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David B. SVXipedia @ SVX-IW.COM -- SVX Information Warehouse 2.0 coming...eventually! Ebony 1992 SVX LS-L 5 spd Koni/GC Stebro 187k miles RIP (Rust In Pieces) 1993 SVX 5 spd Koni/GC Stebro Polyurethane bushings still available! |
#3
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Check your MAF signal or connections.
Does the car have a K&N filter and if so has anyone re oiled the filter lately?
I've seen over oiled air filters cause the MAF to give false readings. Either way if the MAF is not accurately metering of air at intake and the computer uses lookup tables to relate MAF and 02 sensor readings it may name the 02 sensor but be completely wrong. I suggest this because it sounds like you've allready replaced the 02 sensor. How did you obtain the code and definition? If you are using a scan tool then it may be trying to identify which bank the sensor is on. Good luck. Last edited by SEA Sleeper; 06-14-2005 at 05:09 PM. |
#4
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I don't agree
sorry sea sleeper, I don't want to make enemies especially as new as I am to the community so with ALL due respect, I disagree. as a technician I can hoestly tell you that an air mass meter reading does not effect 02 codes. atleast not 95% of the time. you would get 2 codes. the reason for this is because the 02 sensor does not cross reference anything with an ECM. the 02 sensors' ONLY job is to keep the catalyst alive. it JUST SO HAPPENS that a perfect burn is 14.7 a/f ratio. so, while the computer is in closed loop operation(using 02 sensor and TP sensor to make decisions) the 02 sensor is constantly trimming fuel to meet an AFR of 14.7:1. remember, the 02 sensor is measuring parts air not fuel. if you do not have a rear 02 sensor, this is probably attributed to an untrained tech seeing a bank 2 sensor or something and thinking it means the rear 02 sensor. we all know that obd1 cars have no rear 02 sensor. atleast not most.
a word on air mass meters. air mass meters measure air MASS. not pressure or speed(that would be a speed density car using a MAP sensor to calculate fuel). air mass meters on this car are hotwire style sensors. they have a wire that they heat through a controlled short circuit and measure how quickly they cool, cross it with a linear resistance table and subsequently supply fuel accordingly. it is true that an air mass meter could be taking a dump and not supply a proper signal thus causing too little or too much fuel however as long as they do not cross their voltage threshold you get no codes. it has been my experience that a MAF causing an over or underfueling problem is so far out of it's voltage range you get a MAF code. could you get an 02 code as well? maybe, but you would have both and not just one. I would pull the codes yourself, list them here, and we'll do our best to diagnose the car online to save you cash. if you are so inclined, you can monitor your 02 sensors via a voltmeter. just check the signal wire with ground and see what you get with the engine idling. you should see it switching back and forth somewhere between roughly .2 and .8 volts evenly but at a brisk pace. there are a number of 02 codes and problems that cause them but this is a good way to check the sensors general operation. since you have 2, if only one is sticking somewhere, it is a bad sensor. if BOTH are sticking either to a low voltage or high voltage then I would investigate the MAF voltages.. just my 1 cent. 2 is simply overkill on my budget. Last edited by move_right; 06-14-2005 at 05:58 PM. Reason: mistype |
#5
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The code is probably for a "bank 2" sensor, which would be the rear sensor on a car with 1 front and 1 rear sensor. However, on the pre-OBDII SVX with 2 front sensors, it obviously is a reference to one of those. Tell the dealer not to give your car to the new guy in the shop.
Dave |
#6
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'92 SVX misfire dealer lost
Fellers,
the tech thinks it is the spring on the left top intake cam which helps to stabliize the idle. They have looked for vacuum leaks and are somewhat stumped on this one. He even called a subaru tech for help. We had the tranny rebuilt about 6 months 6000 miles ago and my wife says it has had a rougher idle ever since then which would make you think perhaps a vacuum leak but they have checked that. The dealer wants to go in and check the springs, change the timing belt and oil pump while they are in there but i don't have any guarantee it is the acutal problem. The codes pulled are 33 and 36 i believe. please help thanks Tdog Cincinnati, Ohio |
#7
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That spring is meant to keep the gear teeth tight against each other to minimize slack in the drivetrain. He thinks that's the cause of a rough idle? I'd start by replacing the bad O2 sensor that was previously diagnosed (#2 is the left one). Sounds like these guys are on a hunting expedition at your cost.
Dave |
#8
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have them or do it urself, replace both 02 sensors. Idle would really be more orientated towards sensors or dirt in the throttle body. The spring on the intake cam would make some noise(more than likely) if it was broken, they don't just come loose. Try to 02 sensors and work from there. Don't let them tear younr engine apart at your expense, and you don't really need a new oil pump as lng as you have been up to date with oil changes, they are self lubricating so in reality they won't go bad for a long time. Well I hope you get it figured out without spending too much
Tom |
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