Wednesday, November 24, 2010

How do i tell if my engine is backfiring or misfiring ?

i recently changed my spark plugs,rotor,wires, and distributor cap. once i finished installing every ting,i started the car and when i step on the accelerator, the car jerks, then returns back to normal operation. when i look under thee hood and have some one step on the gas, when the car misfires or backfires, there is white/gray smoke that comes out of the driver side of the carburetor area ! the car does this every time i step on the gas, it isn't continuous, its more of on and off when i press the gas pedal.

what is my problem and how do i fix it ?How do i tell if my engine is backfiring or misfiring ?
just a real simple 5 minute diagnosis for back firing is double check your high tension lines. are they going from the correct tower to the correct plug. also insure that they are firmly seated on the tower and the plug. something commonly overlooked is did you make sure you placed the wires back in their looms so as to not let them arc against something metal. electricity will always take the shortest path to ground. if one of these wires can discharge its spark by arcing, easier than firing the plug, it will. this will sound like a taser going off. %26quot;zap zap zap zap%26quot;.

WARNING: do your checking with the car off. this will save you from getting the beeejeeebers shocked outta you! and the embarrassment of your friend laughing at you while you dance around the yard glowing!

if you are absolutely sure you have the correct wires on the correct towers and plugs, then you have a problem other than this one.How do i tell if my engine is backfiring or misfiring ?
If the change came after your work, go back and check all your work. Unless you do the plug wires one at a time, there's a chance some could have been switched. Make sure the engine is timed right: It sounds like yours is firing while an intake valve isn't fully closed..

I once replaced the distributor cap on a '72 Dodge Colt. It wouldn't start afer that. I checked the timing and it was 40 deg off. I compared the old cap with the new one and discovered they were different- the new one had the connectors that far off.. Repositioning the distributor corrected the problem.How do i tell if my engine is backfiring or misfiring ?
It could be that, you could also have a pin sized hole in the head gasket, i'd get that **** into a garage and look at the gasket and engine block for holes.How do i tell if my engine is backfiring or misfiring ?
You probably mixed up the firing order putting it back together. You may also want to time it.How do i tell if my engine is backfiring or misfiring ?
If it was ok before, then you have two plug wires crossed up. A v8 will hide this at idle, but it will run like crap as soon as you try to put load on the engine. Gm V8 firing order is 18436572. Look on the intake just in front of the carb and it will be shown in raised letters cast into the intake. If you didn't pull the distributor out of the engine, then the 1 plug wire should be the left tower on the dist cap while facing it from the front of the car.The distributor turns right hand (clock wise). The cylinders are odds on the drivers side,1357, and even on the pass side 2468, from the front. Retrace your plug wires. I guarantee you got 5+7 crossed up. Easy mistake even pros make now and then. The cylinder numbers are cast into the intake also, right near where the intake meets the heads.Some of the older gms had the plug wire numbers embossed into the plastic retainer ring that hold the plug wire down on the dist cap.(the ring you threw out,because the after market wire didn't fit it)How do i tell if my engine is backfiring or misfiring ?
timing is off and the engine is backfiring through the intake valves. did you loosen or mess with the distributer? if not then recheck that you dont have either some switched spark plug wires or they were installed one hole off in rotation (i doubt this one) when the timing is set to far out the spark plugs fire before the intake valve has clsed causing the back fire you described exhaust bangs are due to the exhast valve open during the spark. if the wires are all correct in the holes and on the plugs than you must bring the motor up to top dead center on the crank shaft pully (tdc) or zero degreas advance or retatd on the crank, then lift the distributor cap and see if the pointer is aimed at 1 spark plug contact in the distributor cap. at his point it should be if its pointed directly accross then you must turn the motor 1 turn to the next time the tdc mark is lined up. now the pointer should be close. turn the distributer base to line up the cap and the pointer to 1 plug. this should stop the backfires now you simply need to gently turn the distributer till the pointer matches the line on the timing marks your engine calls for usually 6 to 8 degrees advance or so.

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