1988 f-250 w? a 351 windsor is surging...is it the map sensor?
HI. there are several problem areas that will need to be inspected. follow the list below to address this issue further.
1. Fuel Filter. If the filter has not been change recently, this will be the culprit. Clogs in the filter will cause surging. replace if needed
2. Intake Manifold Gasket. Check this gasket for leaks, or worn edges. replace if damage is visible.
3. Fresh Air Intake Hose. This hose may be clogged, or damaged. inspect for these faults. replace if needed.
4. Fuel Pump. A weak, or poorly grounded pump will cause low fuel pressure, in return, causing the surge effect. inspect the fuel pump for these faults. replace if needed.
5. Fuel Injectors. A dirty, or faulty injector will cause the surge as well. inspect the injectors for faults. replace any injector that is faulty.
6. Oxygen sensor(s). A faulty O2 sensor will promote surging as well. This will usually be accompanied by an illuminated check engine light. If this is the case. the O2 sensors should be changed.
7. Carburetor. A Dirty and Improperly Functioning Carburetor will cause the surge effect, also. Check to make sure the carb is functioning correctly(IF EQUIPPED)
8. Map Sensor . A defective manifold absolute pressure sensor may cause a rich or lean air/fuel ratio, excessive fuel consumption, and engine surging. this diagnosis applies to map sensors that produce an analog voltage signal. To check the sensor, back-probe the 5-volt reference wire(with the ignition on), and connect a voltmeter from the reference wire to ground. If the reference wire is not supplying the specified voltage, check the voltage on this wire at the computer. If the voltage is within specifications at the computer, but low at the sensor, repair the reference wire. When this voltage is low at the computer, check the voltage supply wires and ground wires on the computer. If these wires are satisfactory, replace the computer.
With the ignition switch on, connect the voltmeter from the sensor ground wire to the battery ground. If the voltage drop across this circuit exceeds specifications, repair the ground wire from the sensor to the computer.
This concludes the surge inspection chart. you will find the issue in one, or more of the areas stated above.
Nov 10, 2009 |
1988 Ford F 250