Still smelling gas. Desperate for ideas.

[yz300]

Hi again. My wife has an 03 ecotec berlina sedan with a poliauto non injected gas setup. I took it for a gas tune the other day amongst other things and he said it was rich so tuned accordingly. He went over it with his gas sniffer and found no leaks. He speculated that the gas i could smell was unburnt gas from the exhaust as it was so rich. We've been able to smell gas at times for a long time. Before and after putting on a new converter, stepper motor and computer controlling the stepper motor and whatever else it does. I thought we were right this time but my wife smelt the gas again last night. I.ve heard there may be a gas temp sensor in the system somewhere, can these play up at times and cause issues?, if it has a temp sensor that it. Another thing worth mentioning is it seems like turning on the a.c and cruise when on gas makes it more liely to turn on the check engine light that only comes on when on gas. I think it's gotta be something electrical going on. I also replaced the abs module a while back which resolved other warning light issues. Anyone here have any ideas? Thanks in advance if you do, Gus.

 

[Fu Manchu]

If someone has put a sniffer across it I’d be putting it down to rich exhaust.

 

[Fu Manchu]

Also make sure someone hasn’t filled your AC with another gas. Take it to an AC place to have its contents identified.

If you had a leak in the evaporator core inside HVAC box, that would explain it all.

 

[DavesSV6Tonner]

LPG tanks/systems are fitted a pressure relief valve. Perhaps the valve on your tank/system is not holding it's rated pressure. Just a thought.
Pressure Relief Valves

Autogas tanks are designed to withstand even the most extreme conditions.


The tanks are designed with 20% unused volume to allow for any expansion of the LPG in hot conditions.


There is also a pressure relief valve that ensures that the internal tank pressure stays within safe tolerances, even when the tank may be exposed to an abnormal amount of heat.

 

[yz300]

Thanks for your reply Fu Manchu. Can you elaborate at all on what a rich exhaust means? What is the HVAC box? Might there be anything else that might happen to indicate a prob in this area?, the box you spoke of that is. For what it might be worth (i'm no superstar) we never smell gassiness on petrol with the a.c on. Thanks again.

 

[yz300]

Thanks DavesSV6Tonner for your reply. I'll keep that in mind too. You made me remember a hot day a long time ago when i walked past the car in the garage thinking i could smell a tiny bit of gas.

 

[Fu Manchu]

If the car is expelling unburnt gas (fuel) because it’s running rich, then your exhaust will smell gassy. Just like a rich petrol mixture would.

 

[Fu Manchu]

HVAC is Heating, Ventilation and Air Conditioning unit. These are what lies beneath the dash and are hard to get to.

inside that are two components like a radiator. One is the evaporator for the AC and further along the airflow is the heater core. The evaporators can leak inside the hvac unit. If someone has used an ac gas other than factory refrigerant and there is a tiny leak, you will smell a gas like smell. Normal refrigerant won’t have an odor.

 

[yz300]

Thanks again Fu Manchu. Any ideas on how the car could expell unburnt gas after it'd been tuned correctly? Also, it could be worth mentioning we don't smell any gas when the a.c is on when the car's running on petrol. Any advice is greatly appreciated, Gus.

 

[DavesSV6Tonner]

If there is a refrigerant gas leak in the HVAC system eventually all the gas will escape and the A/C will no longer work.