View Full Version : Is Link and dead OČ sensor related ?

Jan Shim
1st May 2001, 07:26
Calling all LINKers !!

I first replaced the OČ sensor at 68,000 kms and now the rex has done 78,000 kms and the sensor is stuffed again ? I understand from Mark that he's had several stuffed OČ sensors the whole time he's been running the Link ECU. My Subaru dealer who's big on modifications says prior to cars fitting Link ECUs, they have never had to change OČ sensors and these days they have to stock more due to increased demands.

I am under the impression that OČ sensors are typically prone to heat damage. Is it also possible that running too rich is also unhealthy for the sensor ? One of Link's problems is idle control on earlier Subaru models, and it's nearly impossible to idle lean without compromising idle stability.

What other reasons are they for such short life span ? I recently blew a radiator hose but that was promptly replaced. The engine didnt even have a chance to overheat before i shut off the engine although coolant was oozing out of the big hose from what appears to be a 0.5 cm tear. Tell me there's a way to not have to change OČ sensors every 10,000 kms !!

1st May 2001, 09:55

it is true that Link idle is generally rich, but it IS possible to get it to a lean idle. But this takes SERIOUS dedication!!! I recall a conversation with Bob on the subject, he has spent many an evening messing around with idle to get a good lean idle! I too have spent many long hours messing around with it.

As for sensors, what you might wanna do is get a Bosch LSM11 sensor, part number 0 258 104 002, it's a high quality unit which supposed to be lead tolerant for about 80,000 kms, I've had one and it worked really well, finally suffered a mecanical failure due to being removed far too many times.... far too many engines... LOL http://bbs.22b.com/ubb/wink.gif

Hope this helps,


Jan Shim
1st May 2001, 10:08
P/N of new OEM sensor is BOSCH A24-631 209 07170 (in case anyone wants it). You said the Bosch LSM11 sensor is lead tolerant-how does being lead tolerant helps with longevity if used in my WRX ? Does a high compression ratio engine also equal higher exhaust gases? I dont have an EGT gauge but I do have a nice shiny BPM venturi pipe which I am seriously thinking of fitting one there.

Is there a web based supplier for these Bosch OČ sensors. In Brunei, I pay B$209 (~GBP80) for a new sensor. I gotta know where i can get new ones cheap.

Jan Shim
2nd May 2001, 13:26
Just fitted the new OČ sensor and confirmed working ok. Left it to idle for extended periods and LambdaLink showed last green as expected.

What i didnt expect was on full throttle, it stayed at first green then progressively leaned out to amber. All this time, I have not touched the Link map and a ZF48 on row 6 cannot possibly produce amber lights on full throttle (not when i had the previous sensor anyway before it got stuffed).

The Part Number on the box is 22690A161 while the number on the sensor shows BOSCH A24-631 209 07170. It has one red, white and black wire whereas previous unit had two whites and one black. Unfortunately, my dealer is pretty hopeless when it comes to these things. Can someone help me check if this part number is indeed correct for a '98 WRX ? The previous sensor I fitted had P/N 22690AA170.

Jan Shim
4th May 2001, 02:32
I re-fitted the JECS ecu last night not expecting anything good to come out of that exercise but merely to satisfy my curiousity that the Link ECU isnt responsible & to see if there's anything else wrong (Check Engine light and all that).

Well, FMD, what i discovered shocked me. First of all, no Check Engine light. Engine starts to warm up, LambdaLink starts to light up led by led. 10 minutes later, took the car for a drive, did a number of WOT runs and LL showed full rich. 20 minutes later of trashing, and LL was still showing rich !!

I have checked and rechecked the Link paramters, nothing looked dodgy and since I'm the only person who has access to the car, not a chance someone could have fiddled with it. Never had this problem before i upgraded to the latest PX chipset. I was also losing fuel pressure from 4 bar dropping to 3.5 bar as revs climb on full throttle with the Link. With the JECS ecu, fuel pressure was held.

Truly weird.

4th May 2001, 07:28

First I'd check out the fuel pressure drop problem, then I'd try using your original Link chip again.