Hello everyone.

I have an '04 Discovery with 108k miles. Had the truck a few years now (got it at 62k) and I absolutely love it. I've done most of the repairs & maintenance myself with help from these forums. Lately I've noticed a few things and over the past 2-3 weeks, I've been getting 3-4 consistent codes. I've done a lot of reading on the forums and in my RAVE manual and I'm trying to piece together the info and decide where to start. I'd appreciate any input.

Here are my codes:

P0150
P0174
P1174 (sometimes)
P1415


Here are some changes I've noticed lately:

rough idle even when warmed up

louder SAI pump (wife is happy I found the source of the "shop vac" under the hood)

SAI pump kicking on for 30 seconds or so every now and then at a stop light or in a drive through, truck well warmed up at that point (this may not be something new, but just something I'm noticing as the pump has gotten louder)

Catalytic converter "eggy" smelling exhaust when I shut off the truck and get out

infamous ticking started up (I'm sure unrelated, but here's to hoping!)


Here are my thoughts...

I installed all 4 new bosch O2 sensors about 10-15k miles ago, so I'm thinking it's not those. Although the pump is louder (I'll probably do the filter fix), I don't think it's the culprit since the codes are all RH side of the vehicle and the LH seems to be functioning properly. So this leads me to think I have an SAI system issue at the Air Control Valve or after... I inspected the vacuum lines and the flex pipe from the valve to the exhaust and didn't notice any bad connections or cracking, so maybe I should start by replacing the RH Air Control Valve? $45 on eBay isn't too bad for a used part, but part of me thinks this isn't the problem because the SAI system isn't in use after the truck warms up, right?? So my idle wouldn't be affected at operating temperature by the Air Control Valve not working, unless it was stuck open...? And if it's stuck open, would that attribute to my "too lean" codes? - more air tricking the O2 sensors into thinking I'm running too lean and more air heating up the cats and making them smell?

Hard to imaging the rough idle and SAI code could be unrelated.

I'm probably over-thinking this and should just replace the valve, eh?

Any input would be appreciated.

- jon

 

My SAI pump used to randomly come on at stop lights even after the engine was completely warmed up. It stopped doing it about three or four months ago and hasn't done it again since. I had done a lot of maintenance and fixes though so it's hard to pinpoint what might have been the fix. Hope you find out what it is.