Hello all.

This is connected to my other thread about repalcing downpipes and removing all CATs...

Question has to do with the future of 02 Sensors... Basically, will they function the same way without the catalytic converters in place?

Mine are heated 3 wire sensors that I think are toast, anyways. I am looking to replace with a set of Denso 3wire Sensors. Since the first days I (think) have had the OXY dummy light on in the dash. She runs way over on the rich side of things. Removed a few of the plugs yesterday,,, plugs that I replaced way back at the beginning of this journey,,, to find them black-ish... Evidence of rich running or idling tooooo much while working on things and not enough real ripping and running on the roads...

All advise, suggestions and information is GREATLY appreciated... Thank you

 

Yes

The sensors are mounted upstream of the converters. They don't know if the converters are present or not


Cheers
DD

 

They might need replacing due to age/laziness or even outright defect but I doubt that the O2 sensors are the cause of the rich running....if that's what you're wondering. They are not the primary mixture control system; they're more of a trimming device. Blackened plugs suggest a problem that is beyond the O2 sensors' ability to compensate for.

Cheers
DD

 

Very good to know. A relief actually. Money don't grow on trees, as they say.

Still, let me try to describe what I am looking at. The placement of the sensors is in the same location on both downpipes, but different on both pipes in the sense that one side has two CATs,,, and the other has only the one.... On the RH side, the 02 sensor comes before (upstream of) the ONE CAT which is found after the downpipe and the olive connection... The RH CAT is situated on the intermediate pipe.

And, unless I'm remembering wrong (at work now) on the LH side (driver's) the sensor was between the TWO CATs. One CAT above, one below, the sensor being in the BEND in the downpipe, just before the downpipe connects (shotty connection) to the intermediate pipe... It ain't pretty.

I don't mean to be a worry wort... Just trying to plan ahead as best I can. Getting shut down,,, when working in the street, sucks!

 

JJJ
If you are running really rich, then first, when the car is warmed up, measure the hydrocarbons, CO, etc. and get a proper reading. If it is high, then first check the fuel pressure. After that report back.

 

Understood... Could be a while,,, but that's ok.

 

If you have an air leak in the manifolds then the O2 sensors will ramp up the mixture to try and compensate.

 

Good point and thank you, James... Yes, I am on the chase. I have changed clusters,,, also part of the chase, attempting to fix a speedO that still isn't working. In that, I shuffled the damn dash warning lights BUT I am pretty sure that the light that I am seeing (and always have) is the OXY light. I think I have bad sensors...

Q: when there is a VAC leak, will that trigger the OXY light?

I think that I have eliminated most all of my VAC leaks. I have idle under control (recently) and I actually believe my butterflies MIGHT just be closed down too tight. I am still suspicious of my PVC and crank fume inlet, tho... Need to get very thorough with a aerosol can with some sort of tester,,, and spray around the upper engine listening for changes.

Thanks!!!

 

So here's what I learned when I came home...

First I measured across the single wire coming from the sensor that I assumed to be the 12v 3rd wire for the heated 02 sensors... I was wrong I think,,, is this a dedicated signal wire??? Maybe someone can make sense of the numbers >>>> on both I got a steady .45 to .48 volts which I guess could mean 4.8??? I should have lowered the setting on the mm. Is that just pinned high?

On the double connector I found the +/- 12.50v lead on one pole and what I expect is ground on the other.

The sensors are heating it seems,,, but honestly,,,, I don't know exactly WHAT to make of the results. This is not my cup O tea... Call me Barney Rubble!

 

I've done a little reading about 02 sensors and think I might have figured some things out. I am thinking the .48/.45 reading might be telling me that the 02 sensor is flat, producing no usable signal for the ECU??? No fluctuations?

I intend to try and get a BETTER reading. I'll try and stick a safety pin thru the ground wire (as a test point) while reading off of the single lead (that isn't part of the 2way connector in this three wire set up). See if I get the same results. I am not sure if using the body as a ground point,,,, while probing the signal .48/.45 wire,,, is the way to GET an accurate reading?

Any suggestions?

 

You really need to use a scope to look at the signal, the DMM will struggle to give an accurate reading with a switching signal. That said if its averaging the signal then around 4.5V would be correct for a standard zirconia type sensor in closed-loop. Have you tried measuring the resistance of the heater element?

 

I don't have a scope. DMM is all I have access to.

 

Jay,

just a quick note. i dont know if you have resolved this or not, but here is my experience of the last two weeks..

My Jag wasnt running rich, but it was not as smooth as it should be, I cleaned all the injector connections, the resistor pack, and ground points. Not much improvement. And I was getting an FF44 code.

So, I replaced both O2 sensors. The error remained. An hour perusing thread came up with what may be the clue. I used Walker sensors, as they were $50 each. But apparently, the ECU is tuned in such a manner that the O2 sensors must respond in 450ms. Only the Bosch sensors do that. Our forum member in Japan found that out the hard way.

So, two points: You will not be able to see anything but an average output with a voltmeter. So if you are seeing a voltage in the range of 0.45, the sensors are working. But if you are going to replace them, dont use anything but the Bosch sensors, And yea, they are $90 each.

If you dont want to spend that much and still want to replace them, I have a pair of next to new Walkers I can send you. Maybe 3 miles on them. They are supposed to be replaced every 50k miles anyway.

Also, make sure you clean the ground at the rear end of the RH intake manifold.

Cheers

 

What about NTK's? They are the OEM sensor for the X300 series and I have always though them to be a high quality supplier. Do you know anything about them? Jaguar specifies their sparkplugs for the engine, so seems logical their O2 sensor should also be sutable.

 

I actually dont know. But given what Ive read, I would be tempted to go with what has apparently solved someone else’s problem

of course, if we could ever find a spec sheet for any of these sensors...

 

Hey Y'all...

I would have been coming back to this (and will be) in the next days. I have my LH downpipe which will replace the CATed downpipe on the LH side, and my middle RH muffler was delivered today, WELSH Enterprises. Ended up paying $170,,, ouch!

So, I have everything I need to complete the exhaust... >>>> praying my exhaust guy can manage manufacturing the two essentially straight intermediate pipes and the flanges to go to the olives on the downpiping connections...

A bung will have to be added to the LH downpipe for the 02 sensor I have.... RH has an O2 sensor as is... And here is the risky part AND a question. A question I HOPE doesn't turn into a thing.

I got 2 NEW Bosch sensors,,,, $18 each. Thing is they DO NOT come with plugs. The idea is to SOLDER or SPLICE them and use the plugs I have with the old sensors... So, the question:

SOLDER or SPLICE???? Or is the whole idea a disaster?

I have these connectors that have the solder built into the shrink-wrap. I used them to "solder" the wires in repairs on my XK8 today. Replaced 3 of the 8 coil plug ins... Total of 12 joints... They can be done with a heat gun and it takes minutes and gives a water proof seal. I liked them for this application.

Like these!
What say you???????


Repaired my broken odometer gear on the 928 today as well... A good fix day!

 

Those are great connectors. I have been using them for a year on my boats and cars. Used them for rewiring the TVR.

My question: where in God’s name did younfind Bosch sensors for $18??? And are they the heated type?

 

Oh ****!!!

I just pulled this up because you asked and I realize they are DENSO SENSORS and not Bosch... Hoping I didn't just make a big mistake... Here is the link, for some reason it just keeps showing me that these are something "I bought"... Let me know if the link works for you...

https://rover.ebay.com/rover/0/0/0?m...2F132578305233

 

Or try the "item number"... 132578305233

I was asking because people say to NEVER solder 02 sensor connectors... Supposedly,,, the sensor "breaths" thru the wire and the spaces between the wire... I just have a hard time believing it because over time, pulling in air (like an air filter) the "spaces" between the wires would get gummed up...? Right?

Anyways.

 

I think that's an urban legend. I'd always solder, as it ensures a good electrical and mechanical connection. Finish with heat shrink tubing and it's corrosion proof. I've seen far too many problems wit crimped connections failing over time.