The Subaru SVX World Network   SVX Network Forums
Live Chat!
SVX or Subaru Links
Old Lockers
Photo Post
How-To Documents
Message Archive
SVX Shop Search
IRC users:

Go Back   The Subaru SVX World Network > SVX Main Forums > Technical Q & A

Reply
 
Thread Tools Display Modes
  #1  
Old 06-14-2005, 03:00 PM
tracedog67
Guest
 
Posts: n/a
'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
Reply With Quote
  #2  
Old 06-14-2005, 04:56 PM
Earthworm's Avatar
Earthworm Earthworm is offline
Meow!
 
Join Date: Mar 2002
Location: Winnipeg, Manitoba
Posts: 11,957
Send a message via ICQ to Earthworm Send a message via AIM to Earthworm Send a message via MSN to Earthworm Send a message via Yahoo to Earthworm Send a message via Skype™ to Earthworm
Best is to check the code yourself.

Check the SVXipedia on http://svx-iw.com/ for how to check the codes.
Reply With Quote
  #3  
Old 06-14-2005, 04:56 PM
SEA Sleeper
Guest
 
Posts: n/a
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.
Reply With Quote
  #4  
Old 06-14-2005, 05:51 PM
move_right
Guest
 
Posts: n/a
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
Reply With Quote
  #5  
Old 06-15-2005, 06:04 AM
red95svx
Guest
 
Posts: n/a
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
Reply With Quote
  #6  
Old 06-15-2005, 08:09 AM
tracedog67
Guest
 
Posts: n/a
'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
Reply With Quote
  #7  
Old 06-15-2005, 10:13 AM
red95svx
Guest
 
Posts: n/a
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
Reply With Quote
  #8  
Old 06-16-2005, 03:59 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
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
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 06:23 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
© 2001-2015 SVX World Network
(208)-906-1122