ECU Code 6/Engine quickly going through fuel...

[Susanoo]

Aww dang, I forgot to check mine out today.

I hope you can do that soon man, I actually took the car to a place since I failed local emission testing. CO was really high, if you wanna know but HC was only 15 points off. They tested all the sensors related to emissions and said they were ok, but that the O2 sensor was responding a little slowly. So that could also be part of the extra fuel usage, a faulty O2, but then again I still dont have the other manifold on.

So...I guess i'll try the other ECU and see if anything changes. Oh and im still gonna check that ECT sensor myself just to be sure...in the end I somehow pissed the mechanic off...somehow I asked "too many questions" and therefore told me "not to bring my toy back" so...yea I'm not sure im gonna trust his testing results too much...

[pickupman6]

Well I went by the shop to get my hatch and bring it home today and grabbed my dvom. I unplugged the ect and tested the car side of the plug with key on engine off and it said 4.999-5v. It was dark so I couldn't check it with it plugged up and running. I will do that tomorrow.

[Hauntd ca3]

dont be concerned with the 5 volts at the ect plug, its the voltage getting back to the ecu thats the important bit.
the tw sensor is a negative temperature co-efficient thermister.
which in plain english means the resistance of the sensor drops as the temp rises.
check the resistance of the tw sensor with the engine cold and as it warms up to normal operating temp.
it will start prob somewhere from 500 ohms or more and will be down to 50 or less when its up to temp if its fine.
the ecu sends the 5v to the sensor and measures the voltage that returns to the ecu, which will rise as the engine warms up, if the sensor is open circuit , there is no return voltage to the ecu, and it will stay in the cold start / warm up maps, which happen to be quite rich in the fuel mixtures and would explain the poor mpg.
if there is no resistance across the tw sensor, replace it, if the resistance is very high( ie still a few hundred ohms when its warm ), replace it.
if it checks out, check the continuity of the return wire between the plug and the ecu plug. dont forget to unplug the sensor before you measure it and disconnect the batt and ecu before checking for continuity between the plug and ecu. no continuity or high resistance, replace the wire.

[pickupman6]

Kinda already said that the voltage will change depemding on the engine temp, but thanks for confirming it.

[Susanoo]

Thanks, Hauntd ca3, for your detailed information. I've unplugged the car from power for the last 5-6 hours in hope that it'll clear the ECU to make sure this code isnt just still stored from after replacing the sensor. I've still yet to test the sensor, but I do wish to be more clear...the voltage I read and reported was the voltage at run/idle.

I'll try to get around to testing the sensor and wire. I just hate tracking down wires from one part of the car to another :P

[Susanoo]

So...I left the positive cable unplugged for about 16 hours and I still have code 6, so after I come back from some errands I plan on mapping out that circuit and checking the wires.

[pickupman6]

First I would unplug the ect and make sure you have 5v with he on engine off. If you do than next I would test the new ect. Just because its new doesn't mean its good.

[pickupman6]

Btw it only takes 30 seconds to reset the ecu

[Susanoo]

First I would unplug the ect and make sure you have 5v with he on engine off. If you do than next I would test the new ect. Just because its new doesn't mean its good.

Im assuming you mean the key on, but the engine off...I get 1.65. With the engine running I read about 2.4...Im getting a lot of interference from the plug wires and its about time for replacement...maybe this is complicating matters? I've never seen such a thing happen before and I figure its odd so I thought I'd throw it out there too. Im gonna look back over the testing procedure and recheck the numbers, then test the ect. However with such low voltages and the fact that these numbers have dropped since I last tested it, I'm thinking its not the sensor but either the ECU or the wires to and from.

Btw it only takes 30 seconds to reset the ecu

Thats what I thought but I guess code 6 pops up fast with voltages as low as they are...

[pickupman6]

If its reading that low unplugged , I would say its a bad ecu.

[Susanoo]

If its reading that low unplugged , I would say its a bad ecu.

Well I replaced the ECU and im now getting 3.6 volts, engine running....

UPDATE: I decided to also check that everything was wired point to point correctly...apparently I wired the two sensors incorrectly...

On the ECT I have the green and white (sensor ground 2) on the white and green from the sensor to the left of the ECT. I forgot what that sensor is called and what it does. However, since I found this im gonna rewire it and see if anything changes.

[Susanoo]

So I went back and finally swapped those wires around and now im getting code 10, IAT sensor. wtf? It never gave me anything but code 6. Soo...I could trace all this around all day. But someone out there has to be able to give me a good explanation as to what could have happened...I cant possibly have wired everything wrong and for it to give me just code 06...

[kentwat]

So does that mean you no longer are getting the code 6?

[Susanoo]

When I checked yesterday, it was only spitting out code 10. However I also notice that my radiator fans dont cut off since I swapped those wires. What could I possibly have done?

[Susanoo]

Update: I did some testing for the wires going to the IAT sensor. On the + side I get over 7 volts and for the - side I can read 3.3-3.6 volts...Gonna look up some testing info to see what this could translate to but any info could help...