Easiest way to determine if car is firing on all 6.....
 

Hi,

What is the easiest way to determine if my car is firing on all 6.....

I am steadily losing power, and backfiring is getting more consistent and frequent, ie: going downhill, on any downshift.......




thanx,

SvK

Listen to it?

Tom

You should be able to hear whether it's running on all six. If it's running too rough to tell, one by one pull the ignition wires off the plugs. Each ignition wire being pulled off will cause the car to idle lower. When you pull one off that doesn't cause the idle to change, you've found your dead cylinder.

Well there are a couple of ways but one is to remove each plug wire one at a time while the engine is running. The engine should be noticably different with each one. If you remove one and have no difference then you may have the culprit.

thanx Rick....

emcon, i'm not sure HOW / what to listen for......

SvK

Ok.......guys

I just pulled ignition wire on each one AND....far left is dead. far right is also dead.....

now what?

SvK

So to make sure that my analysis is right....if during idle I pull ALL except the dead ones...the car should die right?

SvK

new wires, or make damn sure the wires plugged in correctly. you can use a spare spark plug, insert it into what you think is a dead wire and then hold it against a ground. make sure you wear heavy gloves, and start the engine...you should see a spark....if you do, the wire is fine, and its the plug...but I have rarely had a plug go bad...so make sure its seated correctly. BE CAREFULL< and I am not liable...

eh , it might die long before you find the dead one . the engine won't run on 2 cyllinders from 1 side for one thing

you pull #1 , if the idle get's worse
put it back in

proceed to #2
pull it , get's worse ? no
back in

#3 pull it , get's worse ? yes? that one isn't firing.

do continue with #4 5 and six
it might be more than one cyllinder, but probably not more than 2 , that would run really bad..

svandamme........should the idle be reduced by the SAME amount on each plug being pulled, using the above mentioned test?

svK

so....if I'm firing on 4 only........that explains my severe loss of power.......does it also explain my excessive back-firing?

SvK

Check that the tips of the plugs are still attached. One of mine fell off an caused wire to fall off. Then I was running on only 4 cyl. I mentioned this to someone else, and he said it was a common occurance. If this has happened to you; DO NOT REMOVE THE PLUG without retrieving the tip - too easy to slip into the cylender.

Yes, the backfiring would be explained by the non-firing cyl. The gas is dumped into the cyl and never ignites, rather igniting when it's squeezed out in the exhaust system.

VaSteve,

thanx ;-)

more or less, but at idle revs, it's hard to tell

yes that would explain backfiring
the cyllinders are sucking fuel from the carb
but it's not burning

that fuel goes in the exhaust unburned
and the output from the firing cyllinders will ignite it..

OK,

So since I have 2 dead cylinders, as opposed to just 1 dead cylinder.....what does that tell me as to what the cause is?

what i mean is, chances of 2 cylinders going dead at the same time are pretty slim, right?

SvK

You can also check for a cold header pipe off the head. You can do this various ways using fluid, infared laser and temperature crayons.

Pick up a sparkplug tester that simply goes between the distributor cap/spark plug and the wire. You can start it up and see if their is spark. This helps reduce the chance of getting shocked and is easy to spot while the engine should be running smooth.

If you need to comfirm the cylinder is dead, then remove the suspect plug and look at it. It should be obvious if its not firing.

you'de be surprised

bad wires
bad plugs
bad dizzy cap , may be dirty or something

check in that order

pull the bad ones
put a new, good plug in the boot , and hold it against a ground on your car
then check for spark

that tells you if you got current up to the wire

if you do ,then it's your plugs, or the little plug cap missing or something

if you don't
put another wire on the dizzy, check again


one more thing

2 cyllinders, you sure you haven't switched 2 wires on the dizzy??? do check

svandamme...all of you....you are all being very helpful....

checking Dizzy Cap 1st (since 2 cable/plugs going at same time is unlikely)

AND car is starting up.......so the olny thing between that is the Dizzy...RIght?

SOmeone tell me procedure for checking Dizzy, please...(thanx, this is the first time, I'm doing something my self).......

Oh .......is the dizzy cap easy to purchase? Not pep-boys thing is it.

SvK

the dizzy cap is cheap as piss, just don't skip any of te steps
do check the wires with a new plug externally ( just hold it against a ground , you'll see the spark , it's pretty easy to spot, at worst you get zapped, unless you have pacemaker, it's shocking not harmfull :)



might not need to replace the dizzy, just clean the contacts inside