[Lugboot]

Here's one for everyone.  I have an issue right now with my 2000 EV GLS with the 12 valve motor.

When ambient temps are high--mid 80s or so--and am running the van at highway speeds ~70mph or so, and running the AC on manual with air directed to vent and floor, fan speed high, and temp set to about 68-69, for about 40 minutes or so....

the van loses power and goes into what can only be described as "limp mode" and a high-pitched whine can be heard from somewhere up front.  It is easier to hear inside than out.  If you pull over to the side, turn off the AC, idle for a few minutes, the whine does not go away, but you can drive off again normally, leaving the AC off.

The first time this happened, the MIL came on but then turned itself off after a few drive cycles.  It happened a second time and I pulled the codes, which are:

P1128, confirmed (lean condition)
P0442, pending (evap leak, small, been chasing this one for awhile)

It happened a third time, the MIL did not come on, but the codes are the same.

The shop had it yesterday and drove it, but did not replicate.  The ambient temps were lower, though.

Would really like to sort this out as we are planning to head to CO with it in a few weeks and Kansas with no AC is not my idea of a good time.

Any insight?

[albertr]

Do you have access to Bentley manuals? They should have the steps to troubleshoot EVAP system.

Take them with grain of salt, thou. I had P0455 code before (large EVAP leak) and following steps from Bentley my EVAP purge valve (N80) was testing good. Tested everything else and no leaks were found. Replaced N80 valve and bingo! Problem is gone. I have dissected  N80 valve and found that it got clogged internally with activated charcoal from EVAP canister! I guess electrically it was working, but got some internal clog.

-albertr

[Lugboot]

The evap code has been on and off for months with no adverse driving affects but this losing power behavior is brand new and is accompanied by the P1128 code. 

Ironically, i have a Bentley, but not the license to access it.  I should consider ponying up the $55 for the license, methinks.

[Lugboot]

Might be getting closer to figuring this behavior out.  The Climatronic system has vacuum controlled servos. I'm starting to think there's a bad vacuum leak at one of these since the behavior only happens when Climatronic is engaged.  Also, the whistling/sucking noise is getting worse...now bad enough to hear outside the van with the hood up, but it is much, much louder inside the van.

In conjunction to the noise getting worse, the van now wants to stall when it happens.  And when restarted, it barely wants to remain running until things cool down.

The most recent episode was on the way home from a trip to the NJ beaches.  It left us sit at a liquor store in Delaware (good choice of spots) and after it sat for 15-20 minutes, we started it back up, turned the Climatronic to Econ, and drove another several hours with no issues.

[Lugboot]

For reference, here's a thread from VW Vortex that started me down this path, even though it's not the exact same behavior:

http://forums.vwvortex.com/showthread.php?5640499-2002-Eurovan-A-c-vents-roar-when-pressing-the-gas

And a specific post from that thread:

"Just took care of this on our 2000 MV....
For some reason, when you step on the gas when the climate control is on "AUTO", the climate computer shifts into recirculate mode. The vacuum motor that controls the recirculation flap does not work on my van. When the computer tries to activate this valve, it leaks. That doesn't allow sufficient vacuum to keep the flap to the center dash vents open, hence the loss of air flow and extra noise.
This vacuum motor (part # 7D1820625) is in the far right hand side of the air distribution housing that contains the fresh air fan, etc., and is accessible from the passenger side. There is a removable panel under the passenger air bag, that allows you to reach up to the vacuum motor.
I haven't pulled the vacuum motor yet - it is held by two screws in a really tight spot. Until I get a chance, I pulled the vacuum hose (Black with green stripe) off the vacuum valve rail (N53 in the Bentley - bright red box) and put a plugged piece of hose on the rail. I don't have a recirculate mode, but I also don't have my wife asking me what the heck is wrong with the air conditioning.
As I said above, this only happened when the climatronic was in Auto mode, or the recirculate feature was turned on. Can anyone explain why the computer would want to recirculate airflow when accelerating?"

This morning I also spoke to the shop that does most of the maintenance on our van, and based on the behavior I reported and his own research, he is leaning towards the controls of the recirculation flap as well.

[Lugboot]

So, I'll bring some closure to this thread.  Based on troubleshooting while on a driving vacation (does not equal a low-stress vacation, btw), the issue was narrowed down to a heat-related electrical fault causing fuel starvation across all cylinders.  It only happened when the under-hood temps got hot enough or there was enough load on the engine for a long enough period of time.  There was never an engine overheating issue.  The coolant temps never budged from the 190 on the gauge (I know there's fudge built into the gauge, but still a valid indicator).  Not running the AC helped delay the issue, but ambient temps and engine load (like climbing a pass) were the determining factors.

So, how did I fix it?  I traded the van and our 1995 Land Cruiser on a 2014 Toyota 4Runner.  Consider this the straw that broke the camel's back when it came to dealing with this particular van.  I may purchase another one at some point, but not soon!