93 Classic LWB Code 44 - Part of a larger problem?

[lsawicki]

I just had a rather expensive fix up to take care of the laundry list of problem I had on my 1993 range rover with 142k miles on it. It ran perfectly (minus the slightly rough idle) for a good month and a half until now. After some erratic idle and stalling, the check engine light came on and the diagnostic screen gave me code 44 (left 02 sensor). I've had this code pop up almost exactly one year ago, about 10,000 miles ago, and I replaced both the 02 sensors myself and the problem went away. I've narrowed it down to a couple of problems:



1) Wiring is dirty. I know it is not disconnected because I checked just now. A few squirts of CRC electronics cleaner will do it.

2) Sensor is bad, and after 10k should be replaced. I would probably replace both of them.

3). The problem is larger...a vacuum leak perhaps?

Anyways, I will probably do #1 first, and I would like some input from you guys. Do 02 sensors go bad after 10k?

P.S The check engine went on after towing two sea doos to and from the lake, but the rough idle/dying happened two days ago. I don't think this is from towing, but from my lessons with my rangie, ANYTHING is possible.

Thanks!

 

[joey]

Just a guess, but the rough idle could very well be causing the code to kick on. Remember if the O2 sensors are not getting enough of air mixture it will kick the code, so a rough idle... which could be fuel or air issues or even spark will cause other issues.

 

[lsawicki]

Sparks plugs replaced with Bosch Platinum +4 plugs about a month ago. No apparent vacuum leaks either. How long do 02 sensors usually last?

Yesterday I adjusted the idle by about 150 to 175 RPMS and didn't make too much difference. Now in P she idles at the 750k. Also, when the car starts up which engine/o2 sensors cold, she idles like a champ. In my opinion, I think this is the biggest symptom pointing to o2 sensors?

Thanks for the timely response Joey

 

[joey]

Just curious the the issue start after the expensive plugs? Having worked on a few LR's now and working with several LR techs that I trust. Every time I see something other than Cheap Champions in an older LR (i.e. older then 99 D2 or 98 RR) the tend to have issues with the high end spark plugs. Just a thought and a cheap test.

 

[lsawicki]

No it ran fine with the Bosch plugs for a solid month...I hear that classics run better on the champions that they were designed to run because the stock dizzy/plug wires don't give the newer plugs enough juice. I have an after market dizzy/performance plug wires, so I didn't think I would have any issues with the Bosch plugs

 

[lsawicki]

Also, I noticed that the plunger on my stepper motor does not move very much when I press down on it. The stepper motor has been replaced, but I found it odd that the plunger would not move?

 

[lsawicki]

Update: Code 48.

I gave the stepper motor a good cleaning (the plunger itself was still very clean from the last time I cleaned it, but the seat in the plenum had some carbon deposits). Gave the plunger a shot of penetrating oil just in case, and I am leaving the battery disconnected overnight.

After rummaging through previous stepper motor related posts, I found that sometimes the stepper motor can cause an o2 sensor code. I hope this is my case

 

[lsawicki]

Found the problem to Code 44....the weld on the header for the aftermarket exhaust system sprung a small pea-sized hole. I got that welded up (for free!) at a local exhaust shop. As for Code 48...I replaced the stepper motor with an 89' Chevy Astro stepper motor (looks EXACTLY the same), and I keep getting code 48 after disconnecting the batter for 20 minutes, twice. How long do I have to disconnect the battery before it registers that I now I have new part?