Upper wiring harness 4-pin connector

[mb_love]

I replaced the upper wiring harness today and I'm not sure about the 4-pin connector in the front. Does it have a specific direction? The male is numbered and can spot a dot on the outside of female connector but no numbers inside.

This harness was bad and repaired by previous owner I pray now this is the last piece to the puzzle causing high CO2

 

[gsxr]

The 4-pin connector works in any position - it's designed that way. There are 2 separate temp sensors and they are wired diagonally.

 

[nocfn]

you are a wis-spewing savant!

 

[mb_love]

Thank you so much. Don't know what I would do without you guys!

I went to inspection with only new harness and original MAF today and it was still bad CO2. He said Lambda was fluctuating and sometimes was good. When I came home I saw it's the same fault code (004 Air mass sensor with hot wire B2/2 Volt. too large/small). I will try other MAF I have also but still suspect it could be something else since nothing have changed.

If new MAF works both harness and MAF was bad. I will check tomorrow.

When I replaced harness the small two pin connection on the right side of engine had a shortage no insulation on wires.

 

[mb_love]

New MAF and rubber fitting. On idle CO2 is around -0.2 to 0 I couldn't measure at different RPM:s. Maybe it could be solved I'm too afraid to hope. Like when I tried this MAF before sometimes idle isn't stable. I should probably read threads but is it something I need to reset installing new MAF?

 

[gsxr]

A faulty MAF could, possibly, affect LH adaptation over time. Ideally you'd reset LH (fuel injection) adaptation and then drive the car a few hundred km's to let it re-adapt with the "new" MAF.

If you have access to SDS / HHT-Win to view live data, check the airflow readings with the engine at operating temp. Details are in this thread.

 

[mb_love]

Thank you!!

I feel it's this button to reset. No master of SDS / HHT-Win but will be able to check values later against the thread you shared.

 

[gsxr]

Yes, that is it! The HHT-Win will show you current adaptation values. Take a photo of the old values before resetting. If they are very high (1.1xxx+) or very low (0.85xx or less) that indicates something isn't right, causing values to be outside the normally expected range.

 

[mb_love]

Do I need to select 2:nd option Perform self adjustment or will it start automatically after resetting?
I drove a lot today still more to go

 

[gsxr]

If desired, you can "perform self adjustment" to speed up the process. Follow the instructions on screen. It may take several attempts. This will get you a ROUGH adjustment, afterwards the module will continue to make fine adjustments automatically.

Or, just drive the car and it will adjust over time.

 

[mb_love]

I feel self adjustment don't look good and CO2 really high now. Could it be lambda sensor? Idling voltage from sensor fluctuates from around 80mV to 750mV. Only sensor and LH module I haven't replaced.

 

[mb_love]

O2 sensor mounted is 1405400881. I can’t see it mentioned in any threads.
Did previous owner mount wrong sensor?

 

[gsxr]

That number (1405400881) is for the electrical connector, not the oxygen sensor assembly. The date code stamped on there, if I'm reading correctly as "1193", would be November 1993... if so, it could be original!

 

[gsxr]

I feel self adjustment don't look good and CO2 really high now. Could it be lambda sensor? Idling voltage from sensor fluctuates from around 80mV to 750mV. Only sensor and LH module I haven't replaced.

The adjustment values are abnormally high. The LH module is sensing a lean mixture and is trying to make it richer. This could possibly be from a faulty reading from the O2 sensor, or MAF, or an air leak somewhere in the intake manifold tract.

Normal O2 voltage at idle will oscillate between roughly 0.1v to 0.9v, but you don't know if the numbers are accurate or not. If the sensor is really old, a new one would be a good idea, they are not expensive (details here).

 

[usarover]

I replaced the upper wiring harness today and I'm not sure about the 4-pin connector in the front. Does it have a specific direction? The male is numbered and can spot a dot on the outside of female connector but no numbers inside.

This harness was bad and repaired by previous owner I pray now this is the last piece to the puzzle causing high CO2 View attachment 190637View attachment 190639

Do you squeeze the tabs at the bottom to remove the 4 pin connector?

 

[gsxr]

Do you squeeze the tabs at the bottom to remove the 4 pin connector?

No, the round 4-pin connector should come off pulling straight up.