ST-eater
21-08-12, 01:19 AM
Hi All, currently having a mate after removing an xe loom to rebuild. After taking it off the car I found no end of bodged wires and broken connections. However I've found two wires left near the big rubber grommet. A massive black wire, and a brown thin wire. I'm thinking that the loom 'could' be from a newer dizzy xe, with lambda.
My engine is a 20xe and didn't have a lambda to start with. The ecu is FP and is correct for the engine.
The thin brown wire goes to pin 24 on the ecu, and I have no idea what this is for. Looking on another loom I have from a different xe, the wires are in
A similar place to the 3 pin lambda plug.
If this is a slightly newer loom to the ecu, do I need to add a pin 20 into the loom and run this to earth? The loom currently doesn't have the female side for pin 20, however I can steal this from another loom I have knocking around.
I'm reading no end of conflicting stuff on here and google, such as ...
If you have a C20XE ECU then it expects a lambda sensor. On the motronic 2.5 engines (early C20XE) GM wasn't so sure that the law would make catted and lambda controlled cars required. So they made the ECU capable of ignoring the lambda sensor by connecting ECU pin 20 to ground. The only uncertainty is what the mixture is set to by default and on the early 20XE engines (not C20XE!) the MAF sensor was equipped with an accessible potentiometer (trimmer) to set the mixture/edjust CO level. The later MAF sensors still have the trimmer, but it is behind a little cap next to the connector. I strongly disadvise to turn the trimmer if you don't know exactly what you are doing, it can destroy the engine if the mixture is set too lean!!
And then...
FP coded ECUs on early GTE 20XEs didn't run a Lambda at all so don't need pins grounding.
And finally...
"pretty sure that the differance is in the loom mate the pre cat ones had an earth wire to pin 20 which disables the lambda function
Can anyone clear this up? The car is using a bit more fuel than it
Should... And has a lumpy idle :)
My engine is a 20xe and didn't have a lambda to start with. The ecu is FP and is correct for the engine.
The thin brown wire goes to pin 24 on the ecu, and I have no idea what this is for. Looking on another loom I have from a different xe, the wires are in
A similar place to the 3 pin lambda plug.
If this is a slightly newer loom to the ecu, do I need to add a pin 20 into the loom and run this to earth? The loom currently doesn't have the female side for pin 20, however I can steal this from another loom I have knocking around.
I'm reading no end of conflicting stuff on here and google, such as ...
If you have a C20XE ECU then it expects a lambda sensor. On the motronic 2.5 engines (early C20XE) GM wasn't so sure that the law would make catted and lambda controlled cars required. So they made the ECU capable of ignoring the lambda sensor by connecting ECU pin 20 to ground. The only uncertainty is what the mixture is set to by default and on the early 20XE engines (not C20XE!) the MAF sensor was equipped with an accessible potentiometer (trimmer) to set the mixture/edjust CO level. The later MAF sensors still have the trimmer, but it is behind a little cap next to the connector. I strongly disadvise to turn the trimmer if you don't know exactly what you are doing, it can destroy the engine if the mixture is set too lean!!
And then...
FP coded ECUs on early GTE 20XEs didn't run a Lambda at all so don't need pins grounding.
And finally...
"pretty sure that the differance is in the loom mate the pre cat ones had an earth wire to pin 20 which disables the lambda function
Can anyone clear this up? The car is using a bit more fuel than it
Should... And has a lumpy idle :)