Mike J

Back in June 2003 I spent a whole bunch of time on this trying to source the connectors from various suppliers including AMP directly. They will supply the parts (and I managed to sample a small amount of them) but the order quanities are what killed it. You need several variants and I seem to remember that the total order was over $20,000. At the time I did this the list did not seem that receptive to what I would have to charge per unit to make it so I abandoned the project...in retrospect maybe I should have finsihed the project.

Here is a quote an part numbers for the connectors. The part numbers I have written down in my old notes are (using AMP numbering):

To intercept each pair of O2 sensors you need (I cannot guarantee these numbers but they are close..its easy to order the mirrors):

2-967-059-1
2-965-261-1
1-967-059-1 Junior Power Timer Socket Housing
1-965-261-1 Mating Tab Housing
929937 is 1.5-2.5 mm² (14 AWG) contact for Junior Timer Socket Housing P/N 962916 is 1.5-2.5 mm² (14 AWG) contact for Tab P/N 963208-1 is Facial Sealing

Two sets are required for car, one for each side. Total of eight connectors/car.

Here is some old pricing:

CAD Quote Expiry June 14/03

1-967059-1 MOQ = 500 $ 3620.55 per TH
1-965261-1 MOQ = 4500 $ 921.98 per TH
963208-1 MOQ = 10000 $ 764.24 per TH

Minimum Quote Value $ 13,601.59. This does not include the female or male inserts, insertion tools or crimping tools.

Here is an old response from AMP about these connectors:

"The 4 POS JR Power Timers are not stocked by our distributors on a regular basis. I have checked all our distributors in North America and nobody has stock. These connectors are designed and manufacturered in Europe. I can get you 40 samples of 1-965261-1, however 1-962338-1 is not a sample room item. Typically we have an MOQ of 2400 pcs with a lead time of 60 days. We show that we have 1200 pcs in Europe, I would need to check to see if I can get these parts. Please advise on the female side. What is your application ? Your company name and address."

I also worked quite a bit with another Rennlister to try to fabricate these connectors but we could not get materials that we could be sure could take the heat for long periods of time. Since then other options such as sourcing out of China have opened up so there might be possiblities.

If any of our Europe based rennlisters are listening it appears these connectors have to be sourced out of Germany and in fairly large quanities.

Now this assumes that the connection is "t'ed off the connector. If people are willing to crimp into the O2 side of the wiring harness (this will only crimp into the O2 side which is replacable) then the kit becomse much easier and cheaper.

Cheers,

Mike

Reynard38

"All you have to do is clamp the the output of the O2 sensors to ground (or close as you can get with a transistor) when the pump is running."

So the way I understand it is the extra air running across the sensors LOWERS the voltage output of the 02 sensors. The circuit is designed to take the O2 sensor voltage to ground to simulate the these effects...correct?

pcar964

I have nothing technical to contribute to this thread - I just wanted to say YES! This is what Rennlist is all about! Good luck on this guys, what a coup for '96+ owners if this thing actually works out!

Mike J

Exactly...when there is extra air runing past the O2 sensor the sensor reports a lean condition (i.e. lots of O2 in the air) which is a low voltage. My understanding is that the computer looks for a lean (i..e. low voltage) on the O2 sensors in front of the CAT that signfifies that air with a high oxygen content is goin gpast (which means the pump is pumping fresh air in). I actually don't know if it also looks at the O2 sensors after the cat although the circuit clamps that output as well.

If this circuit is installed one can effectively disconnect the pump since its not required anyways.

I looked for other spots in the wiring harness where the O2 sensors and the air pump control circuit exists but could not find an easy spot to tap in. My idea was to buy a air pump relay, take it apart and solder a wire/connector to the activation pole of the relay. On the side of the relay a switch can be mounted to turn off the air pump if needed. This way one plugs in the relay and **voila** you have a feed for the controls circuit.

I guess I should have done the product but I got scared with the liablity...but I did put in quite a bit of thought and research before I dropped it back in '03...

Cheers,

Mike

Marv

Is that .45mV or .45 Volts?

If the intent is to suppress the signals at the sensors to <0.45 Volt, you may want to check the diodes that are speced in the modded circuit. They are Schottkey diodes, but their forward voltage drop is rated at 0.525V. That isn't going to get you down below 0.45 Volts. The forward voltage drop on regular diodes is about 0.7 volts. That probably will not be enough unless the gray lead is a negative voltage compared to ground.

Bottom line is that the circuit may not work at all or may be unreliable (works only some of the time on some cars).

All that presumes that the data below is correct.

KOAN

I don't need one yet, but am very encouraged by the discussion and enthusiasm for a fix. I wish I had the technical knowledge to contribute, but I don't. I love seeing the combined effort for the common good. This community is great.

cabrio993

Now...This CAT O2 sensor voltage deal has me thinking... (scary..I know..)

I have heard of many people here that run Cat Bypass pipes and they just leave the O2 sensors hanging in the engine bay and they don't get CEL's. So, if the SAI circuit involves readings from these O2 sensors. Why people that run CAT Bypasses don't get a SAI CEL??

Since the purpose of the SAI is to help the CATs to light up soon enough to burn the rich condition of the cold startup fuel mixture, and since these O2 sensors are disconnected, shouldn't then "CATless people" get SAI CEL's?

Or those out there with CAT bypasses are on MY95?

Anyone here with a MY96-98 running CAT Bypasses?

hoggel

Doh!! I typed it wrong as you suspected. A lean condition is <.45 Volts. I corrected my original post.

hoggel

If people are hanging their O2 sensors in the engine bay then the engine will never be running closed loop. They won't be getting the performance or gas mileage that they should. Maybe just the after-cat O2 sensors are hanging?

Once the O2 sensor heats then the DME starts metering fuel via the injectors to try to maintain the optimum mixture. When it's running closed loop the O2 sensor signal should be crossing back and forth across .45 Volts. If the O2 sensor is reading a lean or rich condition that is beyond the control range then the DME goes to the the stop position.

If the auxillary pump is running then the O2 sensor will send a lean (unburned oxygen in the exhaust) signal to the DME which will increase the Fuel/Air mixture via the fuel injectors. This puts more unburned fuel into the exhaust which mixes/burns with the aux pump air and further heats the cats.

cabrio993

Maybe...I figured they were there for a reason, I just couldn't figured how people that run without the CAT can get away with not plugging the sensors.

Reynard38

I spoke to a friend of mine this morning that had seriously modified some newer OBD2 cars. I explained to him the SAI fault and the bypass circuit. He thinks he can build and install it for me. I will be taking the diagram to him later this week. More to follow.

cabrio993

Mark,

Are you getting the SAI CEL? Otherwise, how would you know that the prototype is working? Just curious....

Red rooster

Rather than get involved with severe enviroment problems and "t" plugs and sockets down around the motor/cats why not pick up the lamda signals at the ecu plug ?Plenty of room for the extra wires with , maybe , a 4 way plug for the circuit box ?

Marv has highlighted a real problem with the 2nd circuit - diode drop + 2n222 "on " voltage is likely to exceed 0.45volts.
Circuit 1 looks more promising especially if a transistor array way used to reduce space.

I dont need any of this but is good to see someone thinking a bit outside the box !!
I look foward to hearing success stories !!!!!!!!!!

All the best

Geoff

hoggel

If someone builds a device they want to test all they have to do is disconnect the vacuum line from the solenoid valve or disconnect the hose from the check valve and there will be no flow from the auxillary pump. That gives the SAI System Malfunction code and a CEL.

Don't try it at home because the CEL doesn't reset itself when the hose is reconnected.

cabrio993

Thanks Hoggel for all the great info. I wonder how many people have gotten a SAI CEL and paid $5K for a head job and maybe all that was wrong with it was a vacuum line or a shot check valve.