$500 for an oxygen sensor?

[OLAK]

It shouldn't affect idle in a big way. If the o2 sensor is not working or absent or the wrong one, as 5-90 mentioned above, the system will not go into its closed loop fuel management when it warms up. You will loose some efficiency in your fuel management and likely get poor milage

 

[5-90]

Wow you guys amaze me all the time the vast wealth of knowlege that is here. My FSM does not tell me which one i have but maybe you guys can. I have a 2.5L 1986 vintage TBI my oxy sensor does not have a plug setup the wires were cut and crimped in. Would this effect the idle if it is the wrong one. Not tryin to steal the thread just tryin to get the info i need.
Thanks John

The RENIX system was used from 1984 to 1990 on the XJ and MJ, when equipped with an AMC engine (meaning the AMC 2.46L/150cid I4 and the AMC 4.0L/242cid I6.) The GM 2.8L/173cid V6 was an OBD-I engine, and I am unfamiliar with the control system that would have been used with the Renault 2.1L/126cid I4 turbo Diesel.

Considering most RENIX parts swap, I'd think that all the RENIX-controlled engines used the "variable resistance dividing a reference voltage" type of HEGO sensor

I'd be rather wary of crossing back and forth - while a variable resistance in place of a voltage generator should cause no harm, I'd wonder about connecting a voltage generator into a circuit using a reference voltage. I don't suppose we can draw old_man into this? As I recall, he's an EE...

 

[bajacalal]

Oxygen sensors used to be much more expensive. So I guess its believeable that it could cost $500 at a dealership back in 1989 maybe. Maybe the guy is just behind on the times.

 

[mr_W]

The RENIX system was used from 1984 to 1990 on the XJ and MJ, when equipped with an AMC engine (meaning the AMC 2.46L/150cid I4 and the AMC 4.0L/242cid I6.) The GM 2.8L/173cid V6 was an OBD-I engine, and I am unfamiliar with the control system that would have been used with the Renault 2.1L/126cid I4 turbo Diesel.

To add some more/less valuable info:

2.1 Renault diesels did not have any electrical control system or engine management system. You could rip out all the wires and it would still run. The only thing that needed +12V supply was fuel cutoff valve which wouldn't let fuel flow if there was no power applied.

Everything else in that engine is mechanical and vacuum activated (I had most of - if not all vacuum lines removed, and it was till able to run).

 

[lawsoncl]

"I'm drinkin' Heartbreak motor oil and Bombay Gin..."
Anyone got any guesses for this one?

Warren Zevon - I'll sleep when I'm dead.

 

[AkJeepKid]

http://www.partsamerica.com/ProductDetail.aspx?mfrcode=BOS&mfrpartnumber=12009&parttype=291&ptset=A

 

[1985xjlaredo]

ok after all of that reading I want to kick this guys ass now! but you should just tell him to give NAPA a call while he is around one day.

 

[Ecomike]

The RENIX HEGO sensor is different (but he's wrong as to why.)

The typical "Titania" HEGO sensor used in most vehicles generates a variable voltage, between 0 and +1VDC, with +.5VDC being a "normal" reading, or "lambda = 1." Under .5VDC, as I recall, indicates a "lean" condition, and over .5VDC indicates a "rich" condition.

The "Zirconia" sensor used in RENIX (and limited other vehicles,) is a "variable resistance" which is fed a +5VDC "reference" voltage by the ECU. The Zirconia HEGO sensor then works as a voltage divider, and a return signal of +2.5VDC is "normal" - with lower voltages indicating "lean" and higher indicating "rich" (again, as I recall. I may have those voltage signals reversed, but the idea is still there.)

This is why you see a lot of posts by me telling people not to use "universal" HEGO sensors in their RENIX rigs - the universal is a Titania type, and is incompatible with the RENIX system. Since the Zirconia only costs a few bucks more, generally, why not just get one that works?

The only HEGO sensors I've seen run anywhere near $500 (and they're more like $300!) are the "Wideband" HEGO sensors used with AFR meters. The conventional HEGO sensor responds on a "knuckle" - you get a linear signal within a very narrow range of AFR (say, 14.0:1 to 15.5:1) and then it's just a flat "rich" or "lean" beyond that. These are typically referred to as "narrowband" or "knuckle" HEGO sensors - I usually call them NHEGO (Narrowband Heated Exhaust Gas Oxygen) when I'm talking about both of them.

Wideband (WHEGO) sensors will give a quantifiable response from, say, 5.0:1 to 25.5:1 AFR, and can therefore quantify just how "rich" or "lean" an engine is running. They're typically used as tuning tools.

Side note - you can change a HEGO sensor yourself on RENIX in about a half-hour - use a HEGO sensor socket if you have one, a 7/8" wrench if you don't. Pull with the engine still warm, it will be easier.

Get a replacement from Borg/Warner, ACDelco, or Bosch - I've had good luck with all three. Make sure there is never-seez on the threads - apply it if not present. Use a socket to reinstall, torque to 21 pound-feet.

Connect the electrics, and have a beer - you're done!

5-90,

What was your source on the Renix & Zirconia O2 sensor voltage, ECU voltage, method and difference (Zirconia versus Titania). I just turned up this post after posting data yesterday on my test results on my current (fairly new, like 8 months old) O2 sensor. I did not see a reference voltage on mine like you mentioned here before, only what looks like a working 0-1 volt O2 sensor that acts like it and the ECU are performing properly to adjust A/F ratios in a closed loop mode. It reads a nice 1 second oscilation rate across the 0.5 volt boundary, and stays in a 0.4 to 0.6 range with a stable idle that widens a bit as I slowly accelerate or decelerate.

I did get about 3 volts going to the heater on the O2 sensor.

 

[Rick Anderson]

Notice the curve for millivolts vs A/F Ratio

Also, it doesn't show it in this graph, but the millivolt vs A/F Ratio curve changes greatly with the temperature of the sensor. Making it even harder to tell what the exact A/F ratio is according to what Millivolts goes thru the O2 Sensor.

But notice 14.7:1 A/F ratio, how broad the drop/swap over is, and that drop/swap doesn't change with temperature.

So, the only thing a typical "NARROW BAND" or "SWITCHING" O2 sensor can do accurately is switch back and forth from hi/low voltage right when you hit 14.7:1.

So they set up the Engine Management to work with the O2 sensor exactly that way, constantly switch back and forth between hi/low voltage, at the right freq of switching you close enough to hold the 14.7:1 A/F ratio, its considered good.

The advantage is the O2 sensor only costs $50.

A WideBand O2 sensor can read A/F ratio with a better gradient of millivolts vs A/F ratio, so its actually possible to read an exact A/F ratio off the voltage coming from the sensor.

But a wideband O2 sensor costs $500.

Like mentioned, your friend may have confused something and thought your Renix System uses one of the very expensive Wideband O2 sensor. Also mentioned, the sensor are not interchangeable, since the signals are so different the engine controller use a totally different scheme on how to manage the A/F ratio, and what signal it is looking for from the O2 sensor.

 

[5-90]

5-90,

What was your source on the Renix & Zirconia O2 sensor voltage, ECU voltage, method and difference (Zirconia versus Titania). I just turned up this post after posting data yesterday on my test results on my current (fairly new, like 8 months old) O2 sensor. I did not see a reference voltage on mine like you mentioned here before, only what looks like a working 0-1 volt O2 sensor that acts like it and the ECU are performing properly to adjust A/F ratios in a closed loop mode. It reads a nice 1 second oscilation rate across the 0.5 volt boundary, and stays in a 0.4 to 0.6 range with a stable idle that widens a bit as I slowly accelerate or decelerate.

I did get about 3 volts going to the heater on the O2 sensor.

As I'd also mentioned in my response to your PM, I'd found the data in the RENIX MPI Overview booklet (which can be found in a few places online - strokers has a copy, and I think Pirate does as well.) It is entirely possible I've gotten the two types reversed - I seem to do that fairly often (and that's why I try to qualify that most time. Did I forget?)

I could also be getting some signals crossed - a "reference voltage" in DC electronics is typicaly +5VDC - but it really could be anything, as long as the reference voltage is known and stable, and the programming is sound (+5VDC just seems to be the convention - but it could also be +1VDC, +10VDC, or even a negative voltage value WRT earth ground.)

You've got me doubting myself just enough that I'm probably going to look this up later to correct myself as well. I gotta stop gettin' hit in the head...

 

[Ecomike]

As I'd also mentioned in my response to your PM, I'd found the data in the RENIX MPI Overview booklet (which can be found in a few places online - strokers has a copy, and I think Pirate does as well.) It is entirely possible I've gotten the two types reversed - I seem to do that fairly often (and that's why I try to qualify that most time. Did I forget?)

I could also be getting some signals crossed - a "reference voltage" in DC electronics is typicaly +5VDC - but it really could be anything, as long as the reference voltage is known and stable, and the programming is sound (+5VDC just seems to be the convention - but it could also be +1VDC, +10VDC, or even a negative voltage value WRT earth ground.)

You've got me doubting myself just enough that I'm probably going to look this up later to correct myself as well. I gotta stop gettin' hit in the head...

5-90,

You were dead on about the voltage difference, etc. I spoke with a Bosch engineer today and got clarification and later discovered a meter error I made.

But first, it seems that the Renix and Chrysler O2 sensors are all Zirconia, (Titania sensor are rare, less than 0.5% according to Bosch) what is different is that the newer ones put out a 0 to 1 volt signal at operating temerature like you said, while the Renix O2 sensor acts like a resistor with the ECU feeding about 5 volts to the O2 sensor (like you said). Turns out 99.5 % of them are Zirconia, but there are 4 kinds of Zirconia O2 sensors (according to the Bosch web site). Won't go into those here, no need.

 

[Ecomike]

5-90,

What was your source on the Renix & Zirconia O2 sensor voltage, ECU voltage, method and difference (Zirconia versus Titania). I just turned up this post after posting data yesterday on my test results on my current (fairly new, like 8 months old) O2 sensor. I did not see a reference voltage on mine like you mentioned here before, only what looks like a working 0-1 volt O2 sensor that acts like it and the ECU are performing properly to adjust A/F ratios in a closed loop mode. It reads a nice 1 second oscilation rate across the 0.5 volt boundary, and stays in a 0.4 to 0.6 range with a stable idle that widens a bit as I slowly accelerate or decelerate.

I did get about 3 volts going to the heater on the O2 sensor.

Once again I have discovered that no matter how experienced we are we can all make dumb :banghead::banghead::banghead: mistakes, like puting the probes in the wrong spots on a volt meter. (high tech analog multi meter in my case has two ground and two positive post holes, one for low volatge one for high).

I had the probes in the high voltage 1kv spots by mistake, then I got the voltage readings I was expecting at the time, so I do not catch my mistake at first :banghead:. So I went back and rececked everything, sure enough my Renix ECU is supplying 4.8 volts to the O2 sensor, it is also getting 12 volts to the O2 sensor heater (so ignor my prior posted data).

Then it read (with the meter set up properly) :banghead::banghead::banghead:
1 - 4 volts and 2 - 3 volts with about a one second swing across the sweet spot of 2.5 volts. And as I increased the engine speed it tightened up nicely to a 2 to 3 volt range and at about 2500 rpm it got down to a 2.3 to 2.7 volt range! Quite impressive. Seems to be able to tighten up the control as the rpm increases on The Renix systems.

Rich Anderson, Nice graphs thanks for sharing!