Today I sampled my voltage signal range of all O2 sensors. I sampled with the ignition on/engine off and again with the engine running. This is what I got.

Bank 1: Upstream ENG/OFF: 86.8mv Downstream ENG/OFF: 79.6mv
Bank 2: Upstream ENG/OFF: 86.5mv Downstream ENG/OFF: 86.9mv

Bank 1: Upstream ENG/ON: 95. Downstream ENG/ON: 148.-150.
Bank 2: Upstream ENG/ON: 95. Downstream ENG/ON: 149.-158.

Can anyone tell me how these ranges are actually effecting the fuel/air ratio. Is it more fuel, less fuel, more air, less air? What are your O2's reading. I ask because the scanner showwed bank 1 & 2 sensor 2's inoperative. I have recently changed them out and still have a fuel consumption problem. I have swapped out my MAF with no change to the engine. Wondering what exactly my O2's are telling my engine to do with these voltage ranges? Anyone???? Still getting around 7-8MPG. Noticed my spark plugs were fouled out with black soot. She is still useing fuel like it is going out of style.

 

The O2's you installed, are they universal, did you splice the wires, were they used?

 

Do a bit of Oxygen Sensor research but keep in mind when you do, NOT all O2's are the same and your Rover uses Titania (not Zirconia) based sensors. They operate as a resistive sensor sort of... a fixed supply voltage is supplied and the return signal is based on the constantly variable resistance. (deja vu).....

If the air:fuel mix is rich, the resistance in the sensor is low. When the fuel mixture is lean the resistance in the sensor is high.

 

Might want to look at Lambda sensor - TechWiki, has info related to voltage readings and conditions they represent. Hope you have the vehicle under the corporation so you can expense that fuel used when demo-ing the regulator rollers.... That is about the mpg I get with my work 454 Suburban towing something.

 

I tossed in two spare O2's that came off my 97D1. The wires were cut so I soldered them to the connector. I don't really think the O2's are the problem because the readings are well within range of eachother.

 

How about a faulty fuel regulator? Would that cause excess fuel use, or is it all in the O2's sending signal to the injectors to dump? I'm still not seeing what my current voltage readings are doing to my engine. With the engine running all the sensors are still comparitively the same signal voltage. Besides the MAF and O2's what else can cause the engine to become rich. Would any of the temperature sensors create this?

 

97 02's are not the same as the 99's. Start there, buy 4 new ones based on your mileage then lets talk about your other issues.

 

Here are the NTK numbers for everyone's entertainment... again

Front Oxygen sensors-


DI and RRC running on the 14cux EFI (1995 and earlier) - NTK 25016
DI w/o AEL - NTK 25017
DI with AEL - NTK 25044
DII - NTK 25624

Do like Mike sez and check which system your '97 has ... *edit* whoops, I thought you had a '97 for some reason.... never mind my figure out whatchu got suggestion.... you can't get away with cheapo substitute sensors... 25044 is what you need to find and BONUS, they're on sale.


apparently BP of Utah is running a sale on the AELS o2's right now... pretty sweet deal....


I coppied this from their site...

Discovery I (96~99) has a specific 'Evaporative Emissions Family' that will help you determine key fuel system replacement parts like the oxygen sensors, fuel pump, fuel filler cap, fuel tank and filler pipe assembly, charcoal canister and more. To identify your 'Evap. Family', check your vehicle information label under the hood on the vertical face of the hood latch panel.
VLR1124AYPFE - Advanced Evaporative Loss System
VLR1060AYPBC - Standard Evaporative Loss System

 

So this morning I removed all my spark plugs and wire brushed them. They were all covered with black soot. She runs better now, but I still can feel alot of engine miss (vibration). The 99D1 O2's are exactly the same as the 97D1 O2's I dropped in. Matter of fact I do not see any difference in the upstreams and the downstreams. They both exhibit the same voltage range. Another question? My plugs are Bosch platinum 2's and my wires are I think 7mm advanced auto specials. Don't remember the brand name. Do you think the vibration problem can be corrected with going back to manufacturer recommended plugs & wires?

 

The Advanced Auto plug wires are pure crap.
The upstream and downstream O2 sensors on a DI are exactly the same.