cylinder #4 not firing

[kawpaul]

Originally Posted by Mike900

I see you're having a real hard time believing this & don't know how we can help. I 1st saw it in a Chilton's manual for a 1989 GM 3800. I just found it on Autozone last night & got the reply back from Dynatek today. I'm sure there's tons of articles if you hit up Google.

I think that youtube video trumps any ideas as to what might be happening. You actually stated you were willing to put $100 on it you were so sure that pulling the cap off plug 4 would kill the fire on plug 1.

I am not saying some of that may not be true. Just that it cannot happen the way you explained it. And reading the autozone link did not actually say what you were saying either. But the coils are the current generators so the spark cannot begin at the plug and travel backwards to the coil. Neither can it jump from one plug through the head to another plug and round trip to the coil. The head would have current flowing through it and you would get shocked by touching the engine if it worked like that.

[scaldwellk]

I am setting back taking all this in and having fun seeing the replies. Lets get to the bottum of this so we can then see if the valves and cam was checked yet.

[Mike900]

Will one of you please explain to me how the secondary windings in a coil can send voltage in two directions at once? Does the voltage start from the middle of the windings & then exit from both sides?

[scaldwellk]

Found this on another site.

The 2 coils system will provide the exact same spark current to BOTH plugs that it goes to. It has to, or else it isn't following fundamental electrical laws. The current flows from the coil, to one plug, through the head, to the other plug, and back to the coil, completing the circuit.

Why it may APPEAR that it is providing different spark distribution is because the plugs are going to wear differently. You have one plug that is firing from center electrode to ground strap, and the other that is firing from ground strap to center electrode. The description of the spark current path will explain why this is.

Look for wear on the opposing edges in the 2 different plugs. For each dual output coil, one will show more wear on the center electrode, the other on the ground strap.

So one coil will fire from + to -. The other will fire - to +. This is in respect to ground. Some people confuse it that the current will flow from one coil to the other, but this is not the case. Remember that neg 12v is more negative then 0v. The coil is made to use 0-12v and -12-0v. If you think that one plug needs the other to fire, that is not true. Disconect a plug and the other will still fire.

[kawpaul]

Originally Posted by scaldwellk

I am setting back taking all this in and having fun seeing the replies. Lets get to the bottum of this so we can then see if the valves and cam was checked yet.

I haven't seen that issue addressed yet. That was my first thought upon reading the thread but got drawn into the debate like a moth to a flame.

Originally Posted by scaldwellk

Found this on another site.

The 2 coils system will provide the exact same spark current to BOTH plugs that it goes to. It has to, or else it isn't following fundamental electrical laws. The current flows from the coil, to one plug, through the head, to the other plug, and back to the coil, completing the circuit.

Why it may APPEAR that it is providing different spark distribution is because the plugs are going to wear differently. You have one plug that is firing from center electrode to ground strap, and the other that is firing from ground strap to center electrode. The description of the spark current path will explain why this is.

Look for wear on the opposing edges in the 2 different plugs. For each dual output coil, one will show more wear on the center electrode, the other on the ground strap.

So one coil will fire from + to -. The other will fire - to +. This is in respect to ground. Some people confuse it that the current will flow from one coil to the other, but this is not the case. Remember that neg 12v is more negative then 0v. The coil is made to use 0-12v and -12-0v. If you think that one plug needs the other to fire, that is not true. Disconect a plug and the other will still fire.

So then we were both half right and half wrong. I would rather know the truth than win an argument because knowledge is power.

Now let us get back to checking that compression.

[stratgooroo]

okay, is it possible to check the valve clearance by just taking out the spark plug because i can see the valves through the hole and they are definitely opening and it seems to me pretty far but im sure it has to be exact so how would i go about doing that? also, why would the cam be flat on only one lobe?

[stratgooroo]

and by the way...the head is grounded so there is no way that the electricity travels through the head to the other side...this is why you put the plug next to the head in order to test spark

[Mike900]

Play along with me, what's the head grounded to?

[scaldwellk]

Originally Posted by Mike900

Play along with me, what's the head grounded to?

Depends what it hits when the person falls?

[kawpaul]

Originally Posted by stratgooroo

okay, is it possible to check the valve clearance by just taking out the spark plug because i can see the valves through the hole and they are definitely opening and it seems to me pretty far but im sure it has to be exact so how would i go about doing that? also, why would the cam be flat on only one lobe?

If you can see the valves are opening then you need to check to see if they are closing fully so you have compression adequate to fire the cylinder. If either valve is too tight it will not seat and that cylinder will not fire.

[scaldwellk]

Originally Posted by stratgooroo

and by the way...the head is grounded so there is no way that the electricity travels through the head to the other side...this is why you put the plug next to the head in order to test spark

You put it next to the head to complete the circuit.

[Mike900]

Originally Posted by scaldwellk

Depends what it hits when the person falls?

I do believe your thinking along the right lines.

I did try StarGate's suggestion & tried to start the bike without cylinders 3 & 4 connected. I don't how but the engine did start. So there is more to this than I thought. I didn't dream up this theory but read it in a book. I still believe the current travels through the head & back to the coils. Besides the book we have the Autozone article, the people at Dynatek and hundreds of postings in the following Google link. There's even mention in one of the Google links that Bosch says not to use their Platinum-4 spark plugs in a waste spark ignition system. Here's a company that that wants to sell as many spark plugs as possible stating the reverse polarity doesn't work well with these plugs. Hopefully we'll all learn something from this discussion.
"waste spark" "reverse polarity" - Google Search

[kopcicle]

Originally Posted by stratgooroo

okay, is it possible to check the valve clearance by just taking out the spark plug because i can see the valves through the hole and they are definitely opening and it seems to me pretty far but im sure it has to be exact so how would i go about doing that? also, why would the cam be flat on only one lobe?

REMOVE THE CAM COVER AND LOOK

I'm done with all of ya ...


~kop

[kawpaul]

Originally Posted by Mike900

I do believe your thinking along the right lines.

I did try StarGate's suggestion & tried to start the bike without cylinders 3 & 4 connected. I don't how but the engine did start. So there is more to this than I thought. I didn't dream up this theory but read it in a book. I still believe the current travels through the head & back to the coils. Besides the book we have the Autozone article, the people at Dynatek and hundreds of postings in the following Google link. There's even mention in one of the Google links that Bosch says not to use their Platinum-4 spark plugs in a waste spark ignition system. Here's a company that that wants to sell as many spark plugs as possible stating the reverse polarity doesn't work well with these plugs. Hopefully we'll all learn something from this discussion.
"waste spark" "reverse polarity" - Google Search

That is basically what I said in post #37.

[StarGate]

Originally Posted by Mike900

I did try StarGate's suggestion & tried to start the bike without cylinders 3 & 4 connected. I don't how but the engine did start. So there is more to this than I thought.

So do you need my address so you can send my money now???

[stratgooroo]

hey does anyone know what the red warning light flashing could mean for this bike... does it have to be reset? im thinking that it could tell me exactly what my problem is but i dont have the book that is specific for this bike so it doesnt say...also, i road the bike for a while today because i changed the petcock diaphram and it seemed to be running on all four again.while i was going down the road it would intermittenly stop running on that cylinder again. everyone was saying that it is a valve or bad rings but now im thinking electric like maybe a coil or bad plug wire. is there anything else besides those two things that could be specific for just one cylinder... a couple weeks ago when i first started noticing the problem, i lost the #3 cylinder as well as the #4 but it hasnt happened since

[steell]

Red flashing light is probably the battery sensor, most aftermarket batteries don't have them so the light flashes until you bypass it with a resister.

Don't know what all the fuss over the ignition coils secondary is all about, the Factory Service Manuals lay it out quite plainly.

A little logic would help an awful lot, show me the ground wire for the secondary side of the coil

Hey, here's a cool idea! Lets take a multimeter and measure the resistance between plug wires, and between each spark plug wire and ground! Maybe that will light the little bulb above your head

stratgooroo, I have to go back and look for your earlier posts to see what bike we're talking about. I thought it was a 84 GPz750.


Edit:

Ok, it is an 84 GPz750.
No check engine light on that bike, no computer

Probably the battery light.

And your problem seem fuel related to me. Have you checked the spark plug on the cylinder that's missing to see what's happening?

.





For any that wish to argue that what I said above about the coils is wrong, think again

I'm almost 60 years old and have been a gearhead since I was ten years old, and a mechanic most of my life (because that's what I like), and I was a computer nerd long before there was such a thing.

And you're going to lose the argument

[stratgooroo]

okay, i have checked all of the wires and traced the electrical all the way and the only thing left seems to be the ic ignitor. does anyone know how much one of these costs?

[MFolks]

The way the ignition coil is set up, #1 and #4 fire together, try switching the leads at the coil and try again. If the problem persists, check the valve clearances as #4 might be partially open.

[Rail]

I have a '80 kz1000 and it wasnt hitting on #1 and #3. I checked for spark and it was good and loosened the drain on the carb bowls and was getting fuel. I rode it down the street and the bike runs good with lots of throttle and with all cylinders running. Idling it misses on #1 and #3. Took carbs off and both pilot jets were plugged. These bikes are notorious for this if they have set up for very long. #4 was doing the same thing a few months back.