1994 Ford Ranger ignition timing off

J.STIEG

MEMBER
1994 FORD RANGER
6 CYL
4WD
MANUAL
156,000 MILES

The truck I am working with is not that responsive and somtimes pops and backfires under heavy load, I checked the ignition timing timing with a strobe light and saw it at 14 degrees before TDC at 1000 RPM, is this normal or not. There is no distributor, vacuum is at 23hg, there is no EEC codes. Truck is drivable but lacks power. Can you give some advice?

Tuesday, June 9th, 2009 AT 12:05 AM

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

At idle speed it should be 10deg BTDC 4degs advance won't hurt-

Probable causes:

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

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Tuesday, June 9th, 2009 AT 1:31 AM