Inertia 500
Active member
I've noticed that after almost every time I wash my 86 coupe, the engine will run poorly for a while. It will stumble and cut out on deceleration and then set a code 33 (MAF too high). I've gone through the troubleshooting sections in the shop manual for the MAF and can find no problems with it but I think what is really happening is that I'm getting some water in the gas from around the gas cap. This throws off the fuel injection system during deceleration because the oxygen sensor goes very lean. The ECM thinks the MAF is bad because the mixture is too lean even though the injectors are passing the right amount of fuel. Of course, since some of the "fuel" is water, the mixture is too lean but not because there is too much air.
After I drive for a while (40+/- miles) everything goes back to normal. The check engine light usually does not come back on the next time I drive the car.
I changed the MAF relays after the first time the car did this but I don't think that changed anything.
Two questions:
Has anyone else had problems with water getting into their gas tanks? I always tighten the lid until it ratchets. The drain hose is clear. However, when washing the car the gas cap will become submerged momentarily.
Does anyone have any comments on my theory as to why the code 33 is set?
After I drive for a while (40+/- miles) everything goes back to normal. The check engine light usually does not come back on the next time I drive the car.
I changed the MAF relays after the first time the car did this but I don't think that changed anything.
Two questions:
Has anyone else had problems with water getting into their gas tanks? I always tighten the lid until it ratchets. The drain hose is clear. However, when washing the car the gas cap will become submerged momentarily.
Does anyone have any comments on my theory as to why the code 33 is set?