Mountaineer AWD V6-4.0L VIN K Flex Fuel (2003)
pintle. An IAC valve damaged by backfire should be replaced. Refer to Figure 1.
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Inspect PCV system for leaks especially looking for cracks along any rubber elbow joints; also verify that the correct PCV valve is installed.
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Inspect for vacuum hoses loose or disconnected from intended ports and connections. Induction backfire can loosen or disconnect vacuum
hoses.
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Two indicators can help you identify if a vacuum leak is present, even if the engine RPM appear normal in the service bay. If the duty cycle is
below specification that is indicative that the engine is receiving too much air (from a vacuum leak) and the PCM is ordering the valve to close
up to restrict flow. Another indication is fuel trim. Record the long term and short term fuel trim PIDS (LONGFT1, LONGFT2, SHORTFT1,
etc.), if short term fuel trims are high (above specification) this is a possible indication of a vacuum leak, making the engine run lean, and the
PCM is attempting to compensate.
IAC Diagnostic Service Tips - DTC 1507 (IAC Under Speed Error) and Other Low Idle
Concerns:
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An under speed error may not necessarily be a fault with the IAC valve. A large friction load on the engine or obstruction in the air intake system
could also reduce the engine RPMs.
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There are four possible sources of friction load that can contribute to under speed error or low idle concerns.
1.
Power Steering Load
2.
Air Conditioning Load
3.
Electrical Load
4.
Automatic Transmission Torque Converter Load
EAC Diagnostic Service Tips - Rough Idle
Concerns:
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Rough idle concerns are often a result of a lean running condition
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Another possible cause is contamination build up on the MAF sensor
EAC Diagnostic Service Tips - Engine Hard Start/Engine Crank-No Start
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While performing diagnostics, the technician should ensure that the fuel system is working correctly for all engines with hard start/crank no-start
complaints.
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When diagnosing a mechanical return less fuel system, the following correction to the PC/ED pinpoint HC (4) diagnostic procedure should be used
when performing the KEOE fuel pressure test:
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Perform the KOEO fuel pressure test as specific in the PC/ED manual.
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The fuel pressure should drop off no more than 10 psi from maximum pressure (no lower than 55 psi for a 65 psi max system or no lower than 45 psi
for a 55 psi max system) within 5 minutes of the start of the test.
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The fuel pressure should drop off to no less than 30 psi within 30 minutes of the start of the test.
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For greatest accuracy, the service technician should read the fuel pressure as soon as possible after pump shut off, no more than 5 minutes after the
start of the test.
NOTE
RETURNABLE AND ELECTRONIC RETURN LESS SYSTEMS SHOULD ALSO BE DIAGNOSED USING THE PROCEDURES LISTED
FOR THEM IN PINPOINT TEST HC.
IAC Diagnostic Service Tips - High Idle RPM at Start Up:
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Most engines will have a temporary high idle at engine start up to allow for catalyst light off. If DTC 1506 is not present, this indicates that there is
no fault present with the IAC.
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A vehicle with very low odometer miles, may exhibit a higher than normal temporary startup fast idle (1600-2500 RPM that decreases slowly). No
