SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSFORD1987CUTAWAY 7.5 LREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISCEC DIAGNOSING & TESTINGCIRCUIT TESTSTEST S - 2.9L, 3.0L & 4.9L EFI FUEL CONTROL
1987 Ford Cutaway 7.5 L

Test S - 2.9L, 3.0L & 4.9L EFI Fuel Control

1987 Ford Cutaway 7.5 LSECTION Test S - 2.9L, 3.0L & 4.9L EFI Fuel Control
NOTE: See HOW TO USE CIRCUIT TESTS  before performing this test. Fuel contaminated engine oil may affect service codes 41 and 42. If this is suspected, remove PCV valve from valve cover and repeat QUICK TEST . If problem is corrected, change engine oil and filter.
  1. Turn key off and wait 10 seconds. Install fuel pressure gauge. Start and run engine. Fuel pressure must be 35-45 psi (2.46-3.16 kg/cm2 ) for 2.9L and 3.0L engines, 50-60 psi (3.45-4.14 kg/cm2 ) for 4.9L engines. Fuel pressure with engine on must be 28-38 psi (1.90-262 kg/cm2 ) for 2.9L and 3.0L engines, 42-52 psi (2.90-3.59 kg/cm2 ) for 4.9L engines. If engine will not start, cycle the key off and on a few times to build up fuel pressure. If fuel pressure is outside range, check electric fuel pump and fuel pressure regulator. If fuel pressure is correct, go to next step.
  2. Turn key on. If fuel pressure cannot hold specification for one minute, go to step 7). If fuel pressure is okay, go to next step.
  3. Fuel Delivery Test. Turn key off. Install fuel pressure gauge. Pressurize fuel system as in step 1). Disconnect fuel pump inertia switch. Crank engine for 5 seconds, then take pressure reading. If pressure drops approximately 5-8 psi (.34-.55 kg/cm2 ) at end of crank cycle, EEC system is not at fault. If pressure does not drop, or complaint was car runs rough or misses, go to next step.
    NOTE: Make sure that fuel is of good quality and not contaminated by air or water, as pressure readings may be incorrect with bad or contaminated fuel. Also, pressure drop will be greater when engine is cold than when engine is warm. If coolant is 200°F (93°C) pressure should drop approximately 10 psi (0.7 kg/cm2 ) in 5 seconds while a pressure drop of 20 psi (1.4 kg/cm2 ) should occur in 5 seconds with engine coolant at 60°F (15.6°C).
  4. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for damaged pins, corrosion or loose wires. Connect breakout box, leave ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance of injector bank one between test pins No. 37 and 58 at breakout box. Measure resistance of injector bank 2 between test pins No. 37 and 59 at breakout box. If both readings are between 5.0 and 6.5 ohms, go to step 6). If not go to next step.
  5. Turn key off, breakout box installed. Leave ECA disconnected. Set DVOM on 200-ohm scale. Disconnect all injectors on suspect bank. Measure resistance of each injector by connecting one injector at a time. Read resistance between test pins No. 37 and 58 for bank 1, or test pins No. 37 and 59 for bank 2. If readings are not between 16-18 ohms, service harness and connectors on injector for possible opens or shorts. If okay, replace injector and repeat QUICK TEST . If readings are between 16-18 ohms, go to next step.
  6. Turn key off, breakout box installed. Connect ECA to breakout box. Connect test lamp between pins No. 37 and 58 at breakout box. Crank or start engine. Repeat test between pins No. 37 and 59 at breakout box. No. light on one or both tests indicates ECA needs replacing if there is 12 volt battery power at pins No. 37 and 57. Repeat QUICK TEST . If bright light on one or more tests, check banks 1 and 2 for shorts to ground. If okay, replace ECA and repeat QUICK TEST . If dim lights glow on both tests, go to next step.
  7. Connect tachometer to engine and run at idle. Disconnect and reconnect injectors one at a time. Note RPM drop for each injector. Each injector should produce a 100 RPM drop. The ISC will attempt to re-establish RPM. If not, replace defective injector and repeat QUICK TEST . If system works properly, fuel delivery is okay. Check for possible vacuum leak.
  8. Turn key off, wait 10 seconds. Disconnect vehicle harness at HEGO sensor. Set DVOM on 20-volt scale. Turn key on. Measure voltage between EGO signal and power ground at HEGO harness connector. If voltage is more than .5 volts, repair short to power in EGO circuit. Repeat QUICK TEST . If voltage is less, go to next step.
  9. Turn key off, disconnect HEGO sensor. Set DVOM on 200,000-ohm scale. Measure resistance between key power input to EGO circuit at HEGO sensor. If reading is 10,000 ohms or less, replace HEGO sensor and repeat QUICK TEST . If reading is 10,000 ohms or more, go to next step.
  10. Turn key off, wait 10 seconds. These non-EEC areas can cause a code 42:
    • Engine oil contaminated with fuel.
    • Misfire caused by ignition.
    • CANP malfunction.

    Disconnect vehicle harness at EGO sensor. Jump (ground) EGO circuit at EGO sensor vehicle harness connector to engine block. Repeat ENGINE RUNNING SELF-TEST. If code 41 is produced, remove jumper and go to next step. If not, remove jumper and disconnect ECA. Inspect for damage or corrosion. If okay, replace ECA and repeat QUICK TEST .

  11. MAP Sensor Test. Turn key off, wait 10 seconds. Remove vacuum line from MAP sensor and install vacuum pump. Apply 18 in. Hg vacuum to MAP sensor. If sensor does not hold vacuum, replace MAP sensor and repeat QUICK TEST . If MAP sensor does hold vacuum, go to next step.
  12. Using "T", install vacuum gauge in intake manifold vacuum line at MAP sensor. Start engine, note vacuum reading. Turn key off, wait 10 seconds. Remove vacuum gauge and "T" and reconnect vacuum line to MAP. Install "T" to different source of manifold vacuum. Start engine and note reading. If vacuum readings were different by more than 1 in. Hg, check vacuum lines for leaks and service as necessary. If not, go to next step.
  13. Set DVOM on 20-volt scale. With EGO sensor disconnected from harness, connect DVOM from EGO sensor to engine ground. Remove PCV hose. Start engine and run at about 2000 RPM. If DVOM reads less than .4 volts within 30 seconds, EGO sensor is okay, repeat step 1). If DVOM reads more than .4 volts within 30 seconds, replace EGO and repeat QUICK TEST .
  14. Run engine at 2000 RPM for 2 minutes. Turn key off, wait 10 seconds. Do ENGINE RUNNING QUICK TEST . If code 41 is still present, go to next step. If not, to step 20).
  15. Turn key off, set DVOM on 20-volt scale. Remove HEGO sensor from vehicle harness.
    NOTE: Following vacuum/air leaks in non-EEC areas could cause a code 41:
    • Leaking vacuum actuator.
    • Engine sealing.
    • EGR system.
    • PCV system.
    • HEGO sensor contaminated with lead.

    Connect DVOM to HEGO sensor and engine ground. Plug vacuum line to MAP sensor. Apply 10 in. Hg vacuum to MAP sensor. Start engine and run about 2000 RPM. If DVOM does not read more than .5 volts within one minute, replace HEGO sensor and repeat QUICK TEST . If DVOM does read more than .5 volts within one minute, go to next step.

  16. Turn key off, install breakout box. Disconnect ECA. Measure resistance between pin No. 49 at breakout box and engine block ground and between HEGO circuit at HEGO harness connector and test pin No. 29 at breakout box. If both circuits are less than 5 ohms, service as necessary circuit with greater than 5 ohms resistance. Reconnect MAP vacuum and repeat QUICK TEST . If both circuits are less than 5 ohms, go to next step.
  17. Turn key off, EGO disconnected, breakout box installed. Disconnect ECA. Set DVOM to 200,000-ohms scale. Measure resistance between pins No. 29 and 40 at breakout box. If resistance is less than 10,000 ohms, correct cause. Reconnect MAP and repeat QUICK TEST . If resistance is 10,000 ohms or more, go to next step.
  18. Turn key off. Disconnect HEGO and set DVOM on 200,000-ohm scale. Measure resistance from power ground to HEGO signal at HEGO sensor. If reading is 10,000 ohms or less, replace HEGO sensor, reconnect MAP line and repeat QUICK TEST . If reading is 10,000 ohms or more, go to next step.
  19. Turn key off. Connect ECA and HEGO sensor. Disconnect and plug MAP vacuum line. Apply 10 in. Hg vacuum to MAP sensor. Start engine and run at about 2000 RPM for one minute. Let engine return to idle. Perform ENGINE RUNNING SELF-TEST. If code 41 is present, inspect pins for corrosion or damage. Reconnect MAP sensor and repeat QUICK TEST . If code 41 is not present, reconnect MAP vacuum line. Go to step 1).
  20. Turn key off. Set DVOM on 200-ohm scale. Disconnect HEGO sensor. Measure resistance between run circuit and power ground at heated EGO sensor. Hot-to-warm resistance is 5-20 ohms. Room temperature resistance is 2-5 ohms. If not within specifications, replace HEGO sensor. If specifications are okay, go to next step.
  21. Turn key on, engine off, set DVOM on 20-volt scale. Connect positive lead to run circuit and negative lead to ground at HEGO harness. If voltage reading is 10.5 volts or greater, HEGO system is okay. Reconnect HEGO and go to step 1). If reading is not 10.5 volts or more, go to next step.
  22. Turn key off, wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance of power ground circuit from HEGO harness connector to battery ground. If resistance is 5.0 ohms or less, service short in run circuit. If reading is more than 5.0 ohms, service open in ground circuit.
  23. Code 41 CONTINUOUS Testing. Code 41 indicates the EGO circuit has not switched during closed loop fuel control. Code 41 does not necessarily indicate a lean condition.
    • Closed Loop: fuel control under influences of EGO sensor.
    • Open Loop: fuel control NOT under influence of EGO sensor.

    Using fuel control service code, determine cause of fuel control problem. Areas to check are:

    • Vacuum Circuits: check vacuum leaks, PCV system, engine sealing.
    • EGO Fuel Fouled: When an over-rich condition has been found to exist, make a thorough check of the ignition system. EGO contamination can be burned-off by driving vehicle at sustained high speeds followed by a few hard accelerations.
    • Ignition System: always in default spark (10 degrees). See QUICK TEST .
    • Improper Fueling: lead fouled EGO sensor.
    • Fuel Pressure: repeat steps 1 and 2).
    • If condition still exists, perform steps 3) and 7) only.

Fig 1: 2.9L, 3.0L & 4.9L EFI Fuel Control Circuits
G12276
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.