02 sensor / running open loop
 

Hey everyone,
Just changed my power steering fluid and serviced my ACE (via mike's instructions... Thanks again Mike). Afterwards, I took the Rover to the car wash to spray off the engine bay to get all the drip drops off everything. I need to stop doing this as every time I do something happens! Last time it was a simple rough idle for a couple seconds and a few misfire codes which immediately went away once everything dried up. No worries, just an edgy spark plug or something.

But this last time I got more. Same rough idle for a couple seconds which went away very quickly. But now my UG shows an open loop and is throwing a p0174 (pretty sure this was it). Could I have either damaged my O2s or maybe loosened some wiring on accident? I have to believe it is connected with the engine wash as this did not happen until right after I did that...

As always, your help and guidance is very appreciated. I have been able to tackle a lot of projects and saved myself some major $$$ because of this site!

the connectors on O2's are known to give off code from oil dripping into them, so i would assume being sprayed with high preasure water could do the same.
You might want to try pulling them apart and cleaning them up with some contact cleaner. I would them coat them with some dielectric grease before putting them back together. Just an idea

Hopefully it will dry out and you can clear it. This is one of thoses codes that takes two drive cycles to show up. Did you get air filter wet?

exceeded RH bank

Also, you may have angered the Rover gods. They like a leaker.

Well I think I found my problem. Last night as I was going through all my electric connections, cleaning them off, and throwing some di-electric grease on them. I was also adding new heat tubing around many of the wires which the original tubing had broken off. While I was doing that, I found a little hose disconnected. Right on top of the engine the clamp on the hose with the arrow pointing to it, was clean off. I reattached it and put a wider clamp on it (luckily I had a couple extra from replacing all my coolant hoses a couple weeks ago).

I am now not running open loop anymore and don't appear to be throwing any codes. Can you help me understand what this hose is for and why it was running open loop with it disconnected?

https://landroverforums.com/forum/me...ereng-3999.jpg

Might be easier to see from the diagram from the RAVE.

https://landroverforums.com/forum/me...reng1-4000.jpg

James, are you still running factory plug wires, they will cause you a lot of grief when wet.
As for that hose, there are 2 of them, one one each valve cover that are then attached to the manifolds to help equalize as well as suck oily air from the engine to be burned off in the cylinder area, it would not cause you to run in open loop once the engine has warmed up.

Hm. Thanks Mike. I do have 8mm blue wires that were replaced about a year ago. New plugs as well.

Interesting that it should not run open loop once the engine has warmed up. It was running open loop all day yesterday, and as soon as I discovered the hose and got it put back on, it has not run open loop or thrown any codes. (It was throwing a p0150 and maybe a p1174 or something like that).

Just a weird coincidence that it has solved itself now?

If you have a real time scanner, and this happens again, see what the engine temp is.
For the most part, it is the ECU that determines if the engine is warm enough to switch to closed loop based on engine temp.

Thanks Mike. I have an UG and my temps are normal. Running about 194 on the highway, about 199 around town +/- a few. I'll keep an eye on it though and see if anything changes.

No what I was suggesting is for you to check the engine when stone cold and watch the temp rise and see when it goes into closed loop. Or test the temp when not coming out of open loop to see what the engine temp is at that time.