Infobit: inexpensive BOSCH heated O2 sensor

[the_sicilian]

does any of this 'heated' stuff apply for a southern california spider?

tifosi, does your 'waiting to warm up' issue come up for you over the summer or just in the spring and fall?

red, you ran this on a motronic without issue? the 56$ one? im about to order one.

[Elio Comello]

The "warm up" issue refers to the Zirconium oxide sensor cell. It needs to be at some 350+ degrees to "do its thing". In the single wire Sensor it would have to wait for the exhaust to heat it up to temperature. With the 3 wire sensor, 2 wires are used for a ceramic heater connected to the 12V. Hence a very fast warm up of the sensor and hence much quicker contol of the mixture richness...

TTFN Elio

[Tifosi]

What Elio said

[Munchen]

Quote:

Originally Posted by Tifosi The other two leads can be tapped on with as long a set of wires as you like to get it somewhere easy to work or deal with. Bosch part # on the box is 15726 and the long Bosch # is 0258005726D09 The point of all this? The standard Bosch replacement for the S3 runs around $100-$110+ and the heated one for the S4 starts at around $120-$140 and both go up from there.

[lasajef]

After reading this thread I installed a 15726 on my '84 with a single wire sensor and it works great. The car used to be lethargic until 3,000 rpm but now it pulls steady through the entire range. Wiring suggestion: I had previously converted my speedometer to a single cable so I used the 30,000 mile sensor light circuit to power the heater wires. It is located in the same vicinity as the connector for the sensor primary wire. I made the splices using the old connectors so everything can be quickly disconnected at the same location. The console light will come on so just unplug the lamp and install a jumper between the wires.
Thanks Tifosi for a great upgrade.

[Tifosi]

Glad to be of service

[Capt Don]

Elio I have not looked at the wiring page my three wire o2 has two whites wires and a black do you know which two are for the heater and which is for the sensor? iam going with the bosch 15735 thanks don

[Tifosi]

White's for the heater, black for the sensor.

[Elio Comello]

Hi Capt!
Tifosi gave you the answer!

Your existing Bosch sensor has the same colour wires. You will have to reuse the two connectors. Cut the old wires leaving enough (generous) so that you can splice the wires. The two whites not polarity sensitive. The Black is the Black.
If you want a neat job, stagger the splices and solder them. use a heat shrink sleeve or tape then an overall heat shrink sleeve.
You will need a purpouse built socket to get the sensor out, your local garage guy will have one, if not Princess Auto or Crappy tire.
I've got my Injectors off to Cruzin'...Found some interesting things..Ms Martellina P will really hum this driving Season!! LOL

Guess unless you have an icebreaker you aren't doing much Captaining these days!

Best regards, Elio

[MAINELYALFA]

I did this upgrade today on my 83 Spider and have to say it is well worth it. The car feels more responsive and has smooth pick up. I used a denso 3 wire for a 88-89 Spider I bought on ebay $25.00.
Jim McGraw

[wutdhec]

So, how much hassle is it taking the old wiring out to splice in with the new sensor and then putting it back? Is there any way to splice it in without removing the wiring and putting it back?

[Elio Comello]

There is no "removal of wiring". You siply cut off the connectors with some retained wire from your old Oxy sensor. You then connect the cut off connectors to the new sensor, which has plain wires and no connectors.

Not too difficult.....Elio

[wutdhec]

Thanks Elio, I asked because in the photos it looked like all the wiring was pulled out to be soldered somewhere other than near the car, but that was my assumption.

[Tifosi]

Some folks pull the whole thing out to do the soldering at the bench, which is likely what you saw.

If you do decide to go that route, it's not too big a deal.

In your case, there will be 3 wires on 2 harness plugs, (single wire on one, 2 wires on the other), all located near the clutch and brake master cylinders. (the single, which is the sensor signal wire, will likely be a green wire with an orange or yellow plug insulator)

Disconnect them, then release the wires from the little hold down thingies on the chassis (the metal tabs that are here and there to guide wires) and drop them down through to the shop floor.

Once you unscrew the sensor, it'll all come right out to be worked on wherever you are conmfortable.

[wutdhec]

Thanks Tifosi - that clears things up for me.