how big is a gas tank in a 1989 mercury grand marquis

In an emissions-exempt application, using the OE Ford engine management system, you can discard the smog pump only if the following are both 'true': You're not running catalytic converters and never drive or start the car below 30 degrees Fahrenheit ambient temperatures. As the engine warms up, based on ECU input from air and coolant temperature sensors, a valve switches the air injection to a port downstream from the O2 sensor but still upstream from the converter, which keeps the converter hot or 'lit off.' With the O2 sensor no longer seeing additional air, it reports a normal 'stoichiometric' A/F ratio (about 14.7:1 at hot idle or cruise). Without the additional smog pump-supplied air, the O2 sensor won't read lean-which means the ECU won't order additional enrichment, causing a cold engine to stall out. With the extra injected air, the O2 sensor reports a 'lean' mixture to the ECU, which then commands additional fuel enrichment for the first 30 seconds of engine operation (it's the electronic version of a carburetor choke). On a cold start, it injects air ahead of the OBD-1 system's O2 (oxygen) sensor mounted upstream (before) the stock setup's catalytic converter. Removing the 'smog' (Thermactor) pump and related valves: This belt-driven air pump adds air to the exhaust. Because of possible turbulence that can result in an incorrect reading, don't locate the meter directly in the cooling fan path.ħ. Recalibrated aftermarket meter/air filter combo 'teams,' which are specifically designed to work as a unit, are available (Pro-M is one source). Don't butt a stock MAF meter directly up against the back of the air filter, either. The MAF should not butt up against the throttle body the delay between actual airflow through the meter versus the amount of throttle opening in the throttle body may confuse the signal to the ECU. If departing from the factory ducting and mounting location, a Ford OE MAF meter ideally needs about 10 inches of straight tubing on either side of it for optimal performance. Bends immediately downstream or upstream from the MAF disturb airflow through the meter, resulting in an incorrect reading. The meter might not work properly if relocated. Mass Air meter improperly installed or located (doesn't apply to 1987 Grand Marquis and other Speed Density vehicles): Factory MAF meter calibration assumes an original OE mounting location.

How big is a gas tank in a 1989 mercury grand marquis