My 2000 EVC has over 100k miles.
In the past few years I've noticed some symptoms, and I wonder if they could be connected:
* very gassy / rich smelling exhaust at startup - not "evacuate the neighborhood" bad but "air out the garage for a while" bad. Definitely coming from the exhaust pipe only.
* after the van warms up, this stops, and subsequent warm starts don't have this problem
* sometimes, a "tick tick tick" noise upon cold start, especially if the van hasn't been driven in weeks. This usually goes away in minutes as the van warms up, and often doesn't come back for days.
* when it's very hot and/or at high altitude, gas fumes - these are not coming from the exhaust, but possibly from the EVAP system hoses around the gas tank or maybe from engine compartment?
* sometimes the tank "gurgles" after filling, and this happens even after I rehabilitated and later replaced my EVAP canister
On the positive side:
* R&R evap canister
* new gas cap
* new N80 valve
* all new plugs, wires, and coil packs (which fixed some misfires, but did not change these other symptoms)
* no codes
* MPG is expected
* passes smog
Basically, if you only encountered this van after it had warmed up, and never took it to the high desert, you would think it was running perfectly.
I have a few ideas - some of these are my own, and some distilled from prior posts on the list:
1. this is all normal, the van always runs in "open circuit" mode at startup, which runs rich, and I'm not remembering how gassy older vehicles are (I do live in California and my other car is an EV).
And, the other gassy smell when hot & high is due to extreme driving conditions (110F, high altitude) and just a flaw with Eurovans.
2. the "tick tick" noise sounds like a hydraulic valve lifter that lost pressure, which could cause incomplete combustion leading to the gassy exhaust.
Once the lifter pumps up, the problem goes away. (This does not explain the hot + high gassy smell, however)
3. it's one of the oxygen sensors? An oxygen sensor malfunction might not trigger a CEL?
But a malfunction could lead to rich running problems, explaining the super rich running at cold start.
Also, (so I've read) oxygen sensors are tied into the N80 (the valve which pulls gas fumes from the tank / charcoal canister and burns them).
If one or both of the Oxygen sensors is bad, this could explain both problems (ultra rich @ startup, and N80 not venting enough).
4. bad fuel injector - it gets stuck open when cold, dumping fuel into the cylinder, but when very hot, leaks into the engine compartment?
(This seems unlikely to me...)
I like #3 because it explains both problems, but am not sold on any theory at the moment, and some of my assumptions are likely wrong.
