So I have a 93 del sol si. When I drive it and turn my heater on since I live in Ohio and it's cold right now, the smell of gas fills my cabin, CEL is flashing code 41, and i'm only getting about 240 miles per tank of gas. I just replaced the Oxygen Sensor on my exhaust header. Also, my coolant temp gauge does not work all the time, and I just replaced that sensor this weekend when I did the oxygen sensor. I know that's a lot, but I don't know what to look for anymore. There are no gas leaks in the engine bay. Help Please! And thanks in advance!

 

Are you sure that it's the smell of gas in your cabin and not coolant? I just went through this with my dad and mom's car and fixed it for them. They both has bad heater cores and when you turn on your heater it causes a smell of coolant/gas come through all your vents and it fogs your window up with coolant haze. I could be COMPLETELY wrong but it just sounds very similar. Wouldn't cause bad MPG though.

 

Check whether the Yel/Blk wire in the O2 sensor connector gets battery voltage with the key in ON(II).

Check whether the heater hose valve on the firewall is stuck closed. If so, manually open it so you can get heat in the cabin.

Check for an exhaust manifold or exhaust pipe leak that may be allowing exhaust gas to enter the cabin. As mentioned, also check for a fuel leak around the fuel filter and fuel rail.

 

hmmm I had a small fuel leak from a a fuel injector o ring once. it was really hard to find.

 

I will have to check the Yel/Blk wire out. I do get some heat in the cabin already and not 100% sure where the heater hose valve is. And lastly I have checked everywhere in the engine bay, exhaust, manifold, fuel rail, fuel lines, fuel filter, and cannot find a leak. I may have to have someone else double check it in case i'm missing something. And yes, it is definately the smell of fuel. I figured since the oxygen sensor isn't working, the ecu is telling it to use more fuel, making it so rich it could be dumping raw fuel into the exhaust. This would explain the bad gas mileage, the CEL, and possibly the smell.

 

Isn't there another oxygen sensor down by the catalytic converter? I believe that is part of the CEL code. http://www.evans-tuning.com/support/...le/obd1-codes/

 

On your car, no. OBD2 cars have a secondary O2, OBD1 cars do not.

 

wow.. didn't know that. I thought obd1 vehicles had two oxygen sensors and obd2 vehicles have 4

 

Maybe in the world of V and H motors, but Hondas are inline (with the exception of the V6 models, which you definitely don't have).