Miss At Idle - Diagnosis (NIS0287AP)

Publication date: 1998-03-01
Reference number: NIS0287AP

MISS AT IDLE - DIAGNOSIS

TECHNICAL INFORMATION TIP

Reference Number(s): NIS0287AP, Date of Issue: March 1998

MISS AT IDLE - DIAGNOSIS

YEAR(S): 1987

MANUFACTURER: Nissan

MODEL(S): Stanza

DATE OF ISSUE: March 1998

ISSUE & TIP

The owner of 1987 Nissan Stanza with 150,000 miles claimed that there was an engine miss at idle. Normal maintenance had of course been neglected on this vehicle, but now he wanted the fuel injectors cleaned or replaced as necessary.

After doing a cylinder balance test, the problem was apparent. Number one cylinder was dead at idle. A compression test showed 140 psi. No vacuum leaks were detected by spraying the intake manifold area with carburetor cleaner. A spark tester on the intake and exhaust spark plug wires revealed no ignition problems. Attaching a propane bottle to the intake to richen the mixture caused the engine to lower its RPM. and didn't pick up number one.

To pinpoint the problem, I removed the number one injector and installed a propane bottle into the injector port in the intake. This was the only way to pick up the number one cylinder. Knowing this showed there had to be a leak in the intake system.

I started removing the intake manifold. After removing the upper intake, there it was. The EGR system was ported to each intake runner. Remember the lack of maintenance I mentioned? Oil residue had clogged the small holes in the lower intake, except for number one. After removing the EGR valve and cleaning it, and using a pick and a blow gun to remove the blockage from the lower intake, the gremlin was purged.

Courtesy of Import Service Magazine

with thanks to:

Audie McCoy

Miami, Oklahoma

REFERENCE NUMBER

NIS0287AP

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