Can my Eec be going bad without codes.

[Itkix]

As title says I'm using a Quarterhorse chip I get my car running pretty good afr's around 14 or so, smooth idle, runs strong, go for a ride 10 minutes or so come back home and tune does a 180 afr's jump to 20, rough idle, only thing I can do to get it back to normal is unplug battery, and that doesnt work all the time, as of today I havent gotten it to go back to normal, everything mentioned above does not happen everytime I go for a drive. Its hard to dial in your tune when this happens. Think it could be eec. Just looking for some ides before I go buy a new eec.

 

[Charlie Allen]

This must be Deja Vu.................I am having very similar issues with a Tweecer, the difference being that I bought a replacement EEC to no avail. I will hold my thoughts until you get a few players on this thread.

 

[toyman]

I'm assuming it's in closed loop. Can you set it in open loop with the QH? If you can, try that and see what the AFR reads. An AFR of 20 is essentially off the map and may be a sign of a failing O2 sensor.

 

[Itkix]

Ive forced open loop and the O2's are new theres something wrong somewhere with either the eec or chip or some spark issue throwing the tune off, as for now mines on the bad side wont run right, might go out tomorrow and it will run normal again., for a while,I don't know what is going on.

 

[toyman]

Ive forced open loop and the O2's are new theres something wrong somewhere with either the eec or chip or some spark issue throwing the tune off, as for now mines on the bad side wont run right, might go out tomorrow and it will run normal again., for a while,I don't know what is going on.

Possibly, but don't assume new means it is working correctly. What were the AFR readings in open loop? That will give you an indication of how close the fuel map is in the idle/low load range.

 

[Itkix]

Open loop and closed loop Afr is the same, doesnt make a difference while its in this running bad stage.

 

[toyman]

Open loop and closed loop Afr is the same, doesnt make a difference while its in this running bad stage.

Which leads me to again suspect the O2 sensor (or maybe the controller). If the AFR feedback from the sensor is 20:1 in closed loop the the EMS will be adding fuel to the bring the reading to whatever is mapped. In open loop the AFR should be the mapped fuel load. At idle or low load conditions that usually results in a AFR between 14 & 15 to 1.

 

[Itkix]

Maybe I can try to disable my driverside o2 with the Quarterhorse then see how it runs if no better switch the driver, pass.,around disable and see what that does.

 

[toyman]

Maybe I can try to disable my driverside o2 with the Quarterhorse then see how it runs if no better switch the driver, pass.,around disable and see what that does.

Are these Wide Band O2 sensors? Just occurred to me that you might be using the stock O2 sensors.

 

[Itkix]

Stock O2's and a lc1wideband for the A/f reading.

 

[qikgts]

If you wanna take the o2's out of the mix just to check the computer and the wideband, run the L4C1 tune with whatever changes you need for fueling; i.e., maf transfer and injector settings.

 

[toyman]

Stock O2's and a lc1wideband for the A/f reading.

Perhaps I'm mistaken but the stock O2's are a narrow band sensor and are not intended to measure an AFR other than 14.7. An AFR gauge with a narrow band sensor has no value and at best are a light show.

 

[2002BLGT]

If you wanna take the o2's out of the mix just to check the computer and the wideband, run the L4C1 tune with whatever changes you need for fueling; i.e., maf transfer and injector settings.

good advice here

 

[Itkix]

Whats a L4c1 tune, heard of t4mo and j4j1 but not that. Just wondering.

 

[qikgts]

It's a factory export tune that doesn't use o2's, runs open loop all the time and has adaptive turned off.

 

[Itkix]

Where do you find that tune, I cant find it.

 

[Itkix]

I just saw it on the other site thanks.