88 Carbed ea81 with code 24

[matrixops]

Well, I'm cruising down the highway the other day going along just fine when I start to notice that the Hatch is "lagging" a bit. At this time the CEL comes on. I continue to my destination without pressing the car too hard. When I return the car to head home the CEL is no longer on, but on the way home the light comes back on and the car starts to behave as earlier in the day.

 

Once I get home, I drop the panel below the steering wheel and watch the LED to see what code is being presented. It is a code 24 which according to the USRM listing for codes is a Temp sensor circuit fault.

 

I did a bit of searching on the forums which basically said to check the connectors on the thermosensor on the intake near the thermostat housing for corrosion. These leads were mildly corroded so I cleaned them up. While I was at it I decided to stick an Ohm meter across the leads to check the resistance. The engine was still warm from the recent driving (not full operating temperature, but warm) and the resistance measured was infinite (open). Now, I am not sure how these sensors operate, but usually they either increase or decrease resistance based on temperature. I have never came across one whith infinite resistance. My question to the board members is this:

 

What kind of reading should I expect from this sensor?

 

Thanks for your help.

 

matrixops

[GeneralDisorder]

Yeah - you need a new sensor. I've had the EA81 feedback carb temp sensors fail as well. The good news is the price is only about $15 for one. It's a double blade connector on it - one side is for the dash guage, and the other is for the ECU so you would NOT see anything on your meter the way you tested it. You need to test each side of the sender to ground. But if the ECU has detected it being fualty, it's most likely the thermistor inside is going out of range or has burnt out completely. It happens - might want to change the 02 sensor while you are doing sensor related stuff. Cheap, and they get old and slow.

 

GD

[matrixops]

GD,

After a quick call to the parts store, they can't seem to find anything in the price range you describe. They have the single pole sendor for $24 and a dual pole one for >$100. Hopefully this is just the wrong part.

 

Update:

After a quick call to the dealer, I was able to get the Subaru Part number which is 21203AA021. They indicate that this part, called a Thermo Gauge, would be $65.60 from them. After calling the local parts store (Advance Auto) with this number, they were able to locate the part for $41.94, but they don't have one available anywhere in the country. I'll call a few more places just to see if they have them.

 

Heck, I would be willing to buy a good used one from someone with a broken EA81 engine if they wouldn't mind selling one to me.

 

Thanks again for your help.

 

MO

[GeneralDisorder]

I'll have a look around my parts - I don't have an EA81 with a feedback setup anymore, but for the short time I did (replaced with a weber when I lifted it) I had purchased a brand new sending unit. Now that I think on it, it's the single pole sender that I've bought for around $10 - $15.... but my local discount parts store had the two pole for less than $25 I think.

 

thepartsbin has it for $22.02. That's not too bad, and it's in stock:

 

http://oem.thepartsbin.com/parts/thepartsbin/quote.jsp?make=SU&year=1984&product=P4036-29938&application=000362622&part=Water%20Temperature%20Sender&category=All&dp=false

 

GD

[matrixops]

GD,

Thanks again, I will be ordering that one right now.