Please confirm my O2 Relay - Page 2

tirwin · tirwin's Garage

I don't see how you could get the results you got with zero resistance across the WUR terminals. It seems to be behaving properly.

Your cold control pressure is just on the low end of normal. Everything else looks fine per the Bentley.

At this point I would move on to other possible problem sources.

tirwin · tirwin's Garage

Good reference for narrowing down potential problem areas:

911 CIS Primer - Troubleshooting

Look at the far left column in the table.

The one thing I'd add to this list is to make sure poor spark isn't an issue. Old plugs, plug wires, cap, rotor, etc can be a contributing factor. You said you've owned the car for two years. Do you have service records that indicate when those things were addressed last? If not, you might want to consider putting those things on the maintenance "catch up" list.

KKothand · KKothand's Garage

Tim, yes I do have the PO records and will go through that. But for the cold start idle, she runs beautifully. That is what is so annoying. Guess I have to go through the rest of the possible causes. Hope I nail this down before Oct-Nov, otherwise it has to wait till next spring..

KKothand · KKothand's Garage

Trying to check the AAR valve (closed or open), and looks like I have to remove the whole top end of the Air box. Is there a better way to take a look at this? Is the rubber hose towards the engine on the AAR is flexible enough that I can push it out of the way to use a mirror, after loosening the c-clamp?

gazzerr · 09:22 AM

Hi KKothand,

You can get it out but like everything else it's a bit of a PITA.

Remove the electrical plug - if it has a metal spring clip you have to remove that first - massive PITA, (lots of swearing - I used a small pick - careful it will spring off into the depths of the engine compartment) then the plug comes off. Then there's 2 capped 5mm(?) allen screws - one under the electrical plug and one opposite on the other side. The AAR is actually attached to the number 5 runner.

Then remove the right side hose - unscrew the clip and lever the hose off with a screw driver (be gentle). It's difficult because the air line is metal and doesn't want to move. Then loosen the hose clip on the left side under the air box and wiggle the whole unit out. This hose is flexible. It actually runs up behind the airbox to the air intake on the rear right of the CIS hat.

I'd also unbolt and move the ac compressor to the right rear fender with a thick towel to one side. I beat the crap out of my forearms with it in.

I've been traveling for work so I've paused on my injectors. I've got 5/6 done. Working on the really hard one on #6. Easy out method didn't work for me (wouldn't budge at all with the easy out in and I'm just destroying the seat) so I'm going to try an improvised neoprene expansion nut puller and see if I can pull it that way ...

Hope that helps.

KKothand · KKothand's Garage

Thank you Gazzerr, this kind of info is exactly what I was looking for before I start tearing into things.
I was going to start with the CSV, but reading other experts here decided to go after the AAR first.

Don't know if I will get to find out the root cause of my cold start problem before Nov, but have to keep working one at a time...process of elimination and all.

gazzerr · 09-07-2015, 04:37 PM

No worries - you can test the resistance across the electrical prongs and it's supposed to be 33 ohms.

If you stick the unit in the oven and heat it to engine temps then the valve should close in about 5 minutes.

My problem was the WUR being out of spec when it's cold. And assorted air leaks that I'm trying to address now.