pistons and firing

[danny nr crew]

ok i know this forum is not for preludes but i jus have a quick ?
wat do u guys think could cause pistons 1 and 2 to not fire
my friend already changed spark plugs and wires and also the distributor does send out electricity threw the wires it just doesnt ignite the gas
any ideas could really help out thanks

[russiankid]

Spark plug gap? Clogged injectors if its EFI.

[Rendon LX-i]

bad compression = blow rings/ring glands

[lostforawhile]

compression? you need air,fuel spark,and compression, and in the right sequence, first check to make sure the plug wires are going to the correct cylinders, if they aren't a couple of them might fire but not all of them

[danny nr crew]

sorry i didnt specify wat kind of motor it has its a b20a3 single cam carb if that help even more
also so if the rings are gone is the motor pretty much crap now?
also how do u check the compression?

[mephi]

If the rings are gone, you are probably going to need to either replace them, or more than likely have the engine bored and honed, and then replace the old cylinders with slightly over-sized ones and new over-sized rings. This is often still cheaper than replacing the car, and you get a larger displacement out of the deal.

There are a few other reasons compression could be down, but first you need to find out what the compression levels are. Get a compression tester from your local parts house, hook it up, disable the ignition system, block open the throttle, and give it a crank. You should get around 3-5 puffs from the cylinder. Look up the specified compression level for your engine, and see how far off they are. They should also all be within roughly 20% of each other. If the compression is slightly low in all cylinders, but they are fairly even, that isn't necessarily a huge problem, but if most are high, and a couple are low, you have issues.

Compression loss is not always caused by worn rings though. You could have restrictions in the exhaust system, you could have a damaged head or a leaky head gasket, and there could also be damage to the cam, various lifter components, or even the valves themselves. A compression test will only tell you if there is a leak or obstruction, not where it is. For that you will need to perform a cylinder leakage test, which requires a slightly different tool.


*First thing though* make sure the wires are connected correctly to the spark plugs. As stated earlier, having a few wires connected to the wrong cylinders can have similar effects. Also, is your engine currently using oil? If it is this may indicate the rings, if not, the problem is most likely something other than the rings.

[lostforawhile]

If the rings are gone, you are probably going to need to either replace them, or more than likely have the engine bored and honed, and then replace the old cylinders with slightly over-sized ones and new over-sized rings. This is often still cheaper than replacing the car, and you get a larger displacement out of the deal.

There are a few other reasons compression could be down, but first you need to find out what the compression levels are. Get a compression tester from your local parts house, hook it up, disable the ignition system, block open the throttle, and give it a crank. You should get around 3-5 puffs from the cylinder. Look up the specified compression level for your engine, and see how far off they are. They should also all be within roughly 20% of each other. If the compression is slightly low in all cylinders, but they are fairly even, that isn't necessarily a huge problem, but if most are high, and a couple are low, you have issues.

Compression loss is not always caused by worn rings though. You could have restrictions in the exhaust system, you could have a damaged head or a leaky head gasket, and there could also be damage to the cam, various lifter components, or even the valves themselves. A compression test will only tell you if there is a leak or obstruction, not where it is. For that you will need to perform a cylinder leakage test, which requires a slightly different tool.


*First thing though* make sure the wires are connected correctly to the spark plugs. As stated earlier, having a few wires connected to the wrong cylinders can have similar effects. Also, is your engine currently using oil? If it is this may indicate the rings, if not, the problem is most likely something other than the rings.do the compression test if it's low on a couple of cylinders, squirt a teaspoon of oil in those cylinders, just a teaspoon or so,use a turkey baster, now repeat the compression test, if it goes up,it's worn rings or a scored cylinder. if it doesn't go up it's other problems.

[mephi]

^that too^

[AccordB20A]

disconnect the coil and crank it over, you should be able to tell by the sound of the starter motor whether compression is even or its down on one or two cylinders