What effect could I expect from having at least Two of my O2 sensors disconnected? I have had the D1 for Three months now and since owning I have removed a broken Catalytic converter on One side and replaced with a straight pipe to muffler (No emission testing needed until 2015). At this time the mechanic noticed the rear 02 Senors had been cut. Only light on the dash is the SBS light, although I have suspicions bulbs are out behind dash as I don't get the standard bulbs on startup (no ABS or other lights) and no readouts on the OBD1.

The only really negative effect I can tell so far is that the D1 might be running rich as I am burning through gas, barely 320KM a tank (unless thats normal..)- replaced the fuel pump and fuel filter recently.

Interested to hear what people suggest.

 

Normally a number of lights come on at engine start for bulb test, and sometimes those just get removed, painted over, cut, etc. Owners manual and shop manual tell which ones come on (warning lights).

198 miles for a tank is low. In reasonable conditions you could expect 15-17 mpg. Low mpg is an effect of O2 sensors. There are methods to "fool" them you can research.

 

You should not run 1 cat and 1 pipe cat causes back pressure so now you have half an engine with back pressru half without, unbalanced I am sure it is not much but it could cause problems IMO

When you turn the key on the see should come on and go out

My down streams are there but I welded the hole closed in pipe and welded extensions on to screw em into they only give a code for cat inop

Buzz I wish I got those MPG

 

As long as there is at least one good O2 sensor on each side it should be fine. The rear act as backups for the front in case one is bad, and vice versa. Of course the ECM will likely complain, but it shouldn't effect operation in any way.

 

Bit of a catch up on this older thread. The rear O2 sensors that were cut are apparently from a D2 pipe that was put in, likely including cats from an old D2. I have since replaced the front O2 after seeing a 44 code on the ODB1 readout, truck still running rich, new code 45, apparently other O2? My mechanic charged an arm and a leg to replace the other 1, not sure why I didn't just do it myself. Is there a difference between left/right bank sensors?

 

No, can be a bear to remove, had to re thread one of mine

 

The D2 uses a different Y pipe IIRC. The pipe on your truck likely came from a 96-99 D1, which use upstream and downstream sensors. Your 95 should have only upstream sensors, same a a 94 would since it uses the Lucas 14CUX system.

Does this truck start running like crap as soon as the thermostat opens? You likely have a bad coolant temp sensor for the ECU, once it hits closed loop the O2's see it is rich because the sensor still thinks the truck is cold.

I would ditch the other cat for the time being, you can replace them both once you get the truck sorted. At this point you are running a restriction on the side with the cat still present and this isn't going to help the situation.

 

Sorry for the delay, been away on business. The truck doesn't necessarily run like crap so not so sure if it's another sensor that's the problem, if I am going to replace the other O2 sensor is there a specific type I need to order? Amazon has NGK on special but is there a specific fitment for a 95 Disco Right/Left bank? Do I just need the tool for fitting or can I use a socket wrench? In terms of the Cat, I think I would like to just replace the missing one to try and return the vehicle to some sense of normalcy, whatever that is?..Anything to gain some MPG and quieten her down a notch.