Check Enigne Light, Fuel System Pressure from gas cap?

[ballhog]

I am checking out this 98 Viper, and the owner tells me the check engine light comes on. Says the car was checked out at the dealer and has something to do with the fuel system pressure and the gas cap. Doesn't have anything wrong with it, however they can't stop the light from coming on. Sometimes the light does not come on, but eventually it comes back on. Suggested he try a different gas cap or disable the light. Anyone ever heard of this?
Older guy, seems like a stand up guy, car has no mods. For some reason I couldn't get the Diagnostic code, with the key trick. I couldn't find anything searching, so maybe its not common. Just don't understand why the dealer wouldn't replace the cap, but then it is a dealer.


Joe

 

[PSilverGTS]

I have a 98 Viper and you can only get the code with an OBII reader that you can rent for free from AutoZone. I had the same check engine light issue with my fuel cap when I added a locking cap (model recommeded on this site). I now use a little bit of silcone spray on the rubber part of the cap. The check engine light will only go out if you disconnect the cable under the hood or use the OBII reader (best way) after you fix the problem. Get the code and if your not sure about how to fix it, post it here.

 

[Jack B]

It doesn't have to be the cap, it can be the canister or the vacuum connection off of the engine. The canister willcost you a bit more than a new cap. Give Chuck Tator a call and he will give you the what-ifs.

 

[RAYSIR]

Any 96 or newer car is OBD2 so has to be done with a scanner, also to reset computer, I had a EVAP code also, I smoke machine tested my 99 RT I bought used and it turned out that they had changed the fuel pump and the gasket for the vent was tweaked and caused a vacuum leak in the tank and turned on the light. Fixed now had to remove the gas tank because fo a dealer screw up. DONT use a keyed gas cap/ If it won't hold vacuum(done every 3 key sterts)thenit sets an EVAP code. The caps leak in the key slot.Every 3 starts there is a motor that pulls vacuum on the fuel tank system and if it sees vacuum doest hold it sets the code and the light.

 

[Fred(DrivingSchool)Kinder]

My check engine light came on my 2002 Jeep. Viper tech replaced the gas cap. No check engine light.