Difficulty fueling in hot weather

mercury
mystique

#1

1998 Mercury Mystique. Something wrong with fuel tank. Can only fill ounces at a time. Any ideas? No problems in the winter.


#2

Have you been in the habit of topping off the tank when you fill it? If so it likely has damaged the vapor recovery system and it will need to be repaired.

Note: I don’t recall exactly when these devices first started showing up on gasoline cars, but I believe they were on 1998s. If you have a sticker in the glove box or under the lid where you put the gas, it has it.


#3

Check Service article 98-15-3. Mercury says this problem could be cause by a swollen flapper ball in the fill pipe. This swelling is cause by fuels containing ethanol. You must remove tank to install new flapper ball (or so the TSB says).

A good mechanic always checks for TSB’s before he makes a diagnosis. If you don’t and there is one (like there is here) you will be laughed out of the shop. Do it to many times and its your job.

We need to back off the topping of the tank blanket advice in these situations and check for TSB’s.


#4

Primitive systems were on cars back in the late 70s. Modern systems are a lot more sophisticated, and are monitored by computers through sensors starting with ODB-II.