Changed out the pre-cat o2 sensors with Amazon NGKs. B1S1 and B2S1 values are now happily jumping up and down.

 

Awesome! Good to hear! Which NGK model number did you use? The NGK # 25044 is the wrong plug type for mine.

 

A couple 25044 did the trick for me.
Yours is pre AELS?

 

Not sure what AELS is. Mine has ODB2.

And some previous owner swaped out one of the connectors to fit that 25044 O2 sensor (left connector in the pic below). but the other o2 sensors are of a different kind (right connector in pic) which look to be the original connectors.

 

AELS Advanced Evaporative Emissions Loss System
How To Identify Emissions System On Discovery 1
Mine has the AELS.

Hmm.. How 'bout that. I don't know if I wouldn't convert the other one over to fit the 25044 as well. The 25017 ares kinda high.

 

Ok. I see what you mean. I have the pre-AELS system it looks like. And someone tried to use a AELS O2 sensor on it. I wonder if that is whats screwing up my o2 reading on my ODB2 readings. Or if the 25044 and 25017 are compatible. I'll do some looking around.

Thanks for the info! Slowly making progress to fix my issue.

 

....it was probably Fish.

Look further up the funky sensors wiring and see if you can't find a spliced section. If not then someone removed the wires from the old connector and put them in the "new" connector. Ah, either way just snag another pre AEL connector from the bone yard or from Paul Grant/Will Tillery and then you'll have all the same.

 

Just so everybody here is on the same page....... 96 was the year Disco's went with the GEMS (Generic Engine Management System) ECU and no distributor. It's pre AEL. Midway through 97 is when the changeover occurred to AEL. How you can tell if it's AEL is the purge canister is square-ish and lays down on it's side. Pre-AEL uses a round purge canister, looks just like a coffee can and sits up vertical. From 97 1/2 to 99 1/2 when the Discovery became the Discovery Series II the Evap system was AEL.

 

Ground, ground, ground. Mine has was doing the same thing. Dim, pulsing and completely out with engine sputtering and dying. I grounded both sides of tranny and both sides of engine. Engine is running smoothly and lights are brighter than ever before.

 

I too am one of the "fortunate" ones with an AEL Disco 1; I just love standing in the cold rain filling the tank at a dribble pace because anything faster kicks off the nozzle. I tried disconnecting the vacuum line from the gas tank at the canister while filling and it helped a little, but is a pita to do every time. Thank you big brother for enhancing my enviornmental safety with this %$#*&^() system.