Joeltron

2.2ltr

The engine starts up just fine when cold but idles very low and just feels sick. When I try to drive it without being at full temperature, it hesitates very badly almost as if it's down a cylinder or something (it is not). When it's all warmed up, it's fine. My first thought was warm-up regulator, but let me run this by you:
My fuel pressure regulator (EHA valve) will sometimes leak a little gas out of this little hole - see picture. It's not really enough to drip or make much of a mess, but you can smell it and when you wipe it away, you can see it seep out of the hole again. Could this actually be the culprit of my lack of power/hesitation? Does anyone have any experience with these otherwise? Thanks!

Joeltron

I'm not sure if anyone cares but I've got a little update.

I replaced the fuel pressure regulator with a used one off of ebay and the coolant temp sensor (on the bottom of the water outlet). The car is running MUCH better. It's got way more power and no more feeling like it's cutting out. I kinda wish I replaced these 2 things one at a time so I could know which one did the trick, but something tells me there were benefits from both.

The car still idles like crap when it's cold though. Next up will be some in-depth vacuum leak searching. I plan to use the cigar method mentioned by Rog.

Side note: anyone ever have trouble with the evaporative emissions control valve, part # 035 133 517 ?
I've seen in other posts where the diaphragm can tear but it's unclear if causes your car to run poorly?

socalclimber

You need to see where your A/F mixture is during open-loop (warm-up) and closed-loop (warm) operation (the signals your ECU is sending the DPR during warm-up and once warm).

See this post:
https://www.audiworld.com/forums/sho...=CIS-E+mixture

or search the forums for "CIS-E mixture".

And, yes, making sure there are no vacuum leaks is also a great idea!

Freeflow90

[QUOTE=socalclimber;24409252]You need to see where your A/F mixture is during open-loop (warm-up) and closed-loop (warm) operation (the signals your ECU is sending the DPR during warm-up and once warm).QUOTE]

agreed. Had a cold start problem a simple bump in a/f made all the difference

Joeltron

That is good advice. Definitely going on my to-do list. I'll let ya know how it works out.