Hi,

Thanks for the offer, but I've already tried a new throttle body. Both the replacement and the original are fully closing the butterfly valve. Nanocom was showing them both open ~3% at idle, which from what I've seen elsewhere is within the normal range. Usually, I'd be second guessing myself, except the shop I had it at for a couple weeks (friend of a friend) spent quite a bit of time ruling out a mechanical problem and they confirmed that the entire throttle assembly is functioning normally -- in fact, the owner had another D2 on hand (they specialize in imports and happened to have one) to compare against. His theory about the high idle was that it was due to my doing the PCV mod from the forum: (https://landroverforums.com/forum/di...4x4-mod-92942/) by using the spring loaded PCV and removing the oil separator.

The change in idle started for me after I got it back from the first shop where they changed the CPS.

One thing I noticed about it, that I didn't catch at first, is that the duration of the high idle before it settles is while the secondary air is running -- it only idles high on cold start.

 

Before selling, try resetting the adaptive values. That should be done whenever the TPS is moved.

Also no mention of engine coolant temperature. Does ECT get to normal in reasonable time? ECT sensor is cheap and easy to replace. Thermostat replacement is a bit more complicated. Maybe setting O2 monitor relies on engine getting to temp quickly.

 

Hey there. Yeah, I reset the adaptive values a few times actually -- whenever I was replacing parts like the MAF, IAC, TPS, etc....

I was letting the engine get up to temp. I replaced the stock thermostat with Extinct's in-line thermostat kit (https://landroverforums.com/forum/di...thread-105010/), so that shouldn't be an issue. To be safe, I relied on the nanocom to let me know when it got up to temp.

I was also running the drive cycles (A-D) with premium gas between 1/4 and 3/4 full.

 

I probably should've consulted with chatGPT earlier on this... One of the symptoms that I had was the high metered air at idle. I just took a look and it's 17 g/s and the trims at idle (with ChatGPT's comments added)

Trim Reading % Adjustment Meaning
Fuel Trim A (STFT) 1.01 +1% Very normal
Fuel Trim B (STFT) 0.99 -1% Very normal
Idle Trim A 1.53 +53% Major correction – running lean at idle
Idle Trim B 1.54 +54% Same – lean condition
Multi Trim A (LTFT) 1.04 +4% Slight long-term fuel addition
Multi Trim B (LTFT) 1.05 +5% Ditto

So, if it's running over 50% lean at idle, its take is "That almost certainly points to a vacuum leak, idle air control (IAC) fault, or unmetered air leak downstream of the MAF."

I'd sprayed carb cleaner around the engine to look for a vacuum leak, but there was no apparent revving. I'm wondering if I ought to invest in a cigar...

 

Do the values change while driving on the highway? Can you block off or disable secondary air for a test?

 

Yeah, I think the last two values for multi-trim are the long term fuel trim values while cruising. They look pretty good.
Are you thinking that disabling the SAI pump might drop the idle trims?

 

Yes, then maybe allow the O2 monitor to set.

 

Hahaha outstanding timing — and thanks for confirming.

I just got back inside after disconnecting the harness for the SAI pump and the idle revs dropped to normal (MAF is still reading high metered air) and figured it’d be worth going for a long drive tonight to see if they set. IF that works, I guess the next step would be to reconnect SAI and hope that monitor sets before the CEL comes on.

 

No luck. Disconnected the wiring harness, reset adaptive values, did a long drive. The O2 heater monitor set (along with cat), but O2 sensor monitor did not set.

 

Then still pointing to bad O2 sensor, wire, or connector. Too bad it does not pinpoint why it doesn't set. If upstreams are working, then could be downstream sensor issue. Maybe a different scanner can do that? At least we figured out the high idle bit.