fault finding

Home ] Specifications ] Members Cars ] Technical tips ] Pontiac Gallery ] Links ] Vin decoding ] Garage scene ] Wiring diagrams ] [ Fault Finding ] Pontiac Articles ] Shows ]

Generator troubleshooting

Generator_1.jpg (116777 bytes)  Generator_2.jpg (192955 bytes) 


Troubleshooting Engine Smoke

Blue Puffs at Start

May indicate damaged valve seals.
The smoke, which in most cases disappears after a few seconds, comes from motor oil that has seeped past the valve seals and into the combustion chamber when the engine is turned off. This is more common in older engines.

There's no cause for immediate alarm. However, since you are burning oil, make sure that the engine oil is filled to the proper level. Problems may occur, however, if a lot of oil seeps into the combustion chamber. This can damage spark plugs and reduce engine performance.

Blue Plumes when Decelerating

The piston rings that seal the oil out of the combustion chamber may be old, perhaps to the point that the piston cylinder walls have been scratched and scarred. The problem is most evident when the engine has been pushing hard and then decelerates.

There is little reason to worry unless spark plugs are fouling or if the oil level is not checked regularly.

Black Clouds

In most cases, fuel-related problems will cause black smoke to puff from the tailpipe. With today's sophisticated fuel-injection systems, you'd be hard pressed to find this problem, but it does happen.

A certified technician should be consulted if the engine is producing an excessive amount of black smoke. For an engine to remain healthy, it needs a constant, correct mixture of air and fuel.

White Vapors at Start-Up

When first started, every engine will emit some white vapors that quickly disappear, especially in cold weather. These vapors are caused by condensation in the exhaust system and are perfectly normal.

Blue & White Smoke

This may indicate a blown head gasket, a fairly serious problem. If there is a problem with the head gasket, the engine will run rough, if at all, and antifreeze and/or oil will reach the combustion chamber. Antifreeze and water will cause white smoke. Oil will result in blue smoke.

A sure sign that there is a problem is if oil is in the water, or water in the oil. As in any case with heavy smoke, a certified technician should immediately check your car to help avoid costly repairs.


Diagnosing Driveline Noise

Whirring noise only while decelerating at any or all speeds is most likely caused by bad pinion bearings or loose pinion bearing preload, and almost never by bad ring and pinion gears.

A howl or whine during acceleration over a small or large speed range is usually caused by worn ring and pinion gears or improper gear set up.

Rumbling or whirring at speeds over about 20 mph can be caused by worn carrier bearings. The noise may change while turning.

Regular clunking every few feet may indicate broken ring or pinion gears.

Banging or clunking only on corners can be caused by broken spider gears, lack of sufficient positraction lubrication, or worn positraction clutches.

Rumble while turning may indicate bad wheel bearings.

A steady vibration that increases with the vehicle’s speed can be caused by worn u-joints or an out of balance driveshaft.

Clunking only when starting to move or getting on and off the gas might be loose yokes, bad u-joints or worn transfer case or transmission parts

eXTReMe Tracker