Plug Purge Valve vac line and retry...

Update:

Jcyuhn: Symptom is not present at cold startup. I'll have to check, but I think O2 sensor is original. Would you recommend replacement as a matter of preventative maintenance?

Mr. Dalton. Thanks for pointing me in the direction of the purge valve.

I plugged the hose on the intake manifold side of the valve, then drove the car. If anything, the symptom seems to be worse. I removed the valve and found about a half tablespoon of what I assume are charcoal granules in the upstream (canister side) valve connection nipple. I suspect that these came from the evaporation canister located upstream of the purge valve. Does the presence of these granules indicate anything? Could they cause the valve to not function correctly? Could a plugged vent line to the canister change the air flow path through the canister thus drawing granules to the valve?

I’m going to look at the canister this afternoon to see if there are any plugged lines. Also, next time the symptom presents itself, I’m going to remove the gas cap and see if that has any effect. Could it be that idle hiccup/burble is the result of excessive vacuum in the gas tank?

Thanks for the help so far.

Any other ideas?


J. M. van Swaay

Update:

Removed gas cap when symptom present--no change.
Checked for unrestricted flow through cannister--OK

Swapped purge valves with known good vehicle. Caused idle surges and unstable idle in good vehicle, but symptom still present in problem vehicle.

Swapped valves back to original cars.

Gave a few squirts of WD 40 to cannister side of valve during run. (recommended in other posts I found on this subject) No change.

Is it possible that the valve is/was indeed malfunctioning but the adaptation has done it's best to correct? Wouldn't this caused an "adaption at limit" code to be stored?

I'll post if I come up with the answer.

J. M. van Swaay

I checked my notes from repairing the car. It was throwing code 13 - rich or lean limit on the O2 sensor. The symptom was more of a fluctuating idle than what I would call a burble or hiccup.

I don't have enough experience with the O2 sensor to recommend replacing it based strictly on age/mileage. Perhaps Arthur or one of the experienced techs can comment.

- JimY

Here is my .02 cents of advice. I would get fuel pressure reading before starting, at idle and after shut off. Hookup the pressure meter to the fuel rail if one available. Sometimes it could be fuel pressure regulator. If the reading are abnormal it could be fuel pressure regulator. it is located on the fuel rail. mine is E420. I am not sure where it would be on E320.

Also, check if any of the vaccum hoses are damaged. white plastic parts are brittle after going through beating from the heat build up in the engine compartment. Do a visual check. I hope this helps.

__________________

Kamal Atwal
2005 Triumph Bonneville T100 (Black/white) [Sold]
2007 GL450 (Dersert Silver)
2009 Toyota Corolla (Metallic Silver)
2002 Tundra V8 - 2WD (Desert Sand)
1995 MB E420 (Silver Smoke) [crashed, now resting in peace at Silverstar Recycling Center]