Smoking engine ?

[rob love]

I theorize stuck valves on these older motors may be because of the ethanol in the fuel. If it is a stuck valve, you can usually fix that right on the vehicle by first identifying which cylinder is the culprit, and then pulling that sparkplug. With a small punch you can gently tap the valve back in place, then crank the engine over and repeat until the valve moves freely again.

To identify which cylinder has the stuck valve, you can start at the exhaust pipe and with the engine running, and your hand in the exhaust stream, feel for the side that has a miss. That will narrow it down to one side. Now for the shocking part. With the engine running, you need to pull the wires one at a time and see if there is a loss of RPM, or an added roughness to the idle. If the plug is pulled and there is no change, then you have found the bad cylinder. This was often referred to as a poor mans compression test. Replace the wire and move on to the next cylinder.

These jobs are much easier with a second person.

[carrierbarry]

Thanks guys I’ll report back

[lynx42]

Originally Posted by rob love

To identify which cylinder has the stuck valve, you can start at the exhaust pipe and with the engine running, and your hand in the exhaust stream, feel for the side that has a miss. That will narrow it down to one side. Now for the shocking part. With the engine running, you need to pull the wires one at a time and see if there is a loss of RPM, or an added roughness to the idle. If the plug is pulled and there is no change, then you have found the bad cylinder. This was often referred to as a poor mans compression test. Replace the wire and move on to the next cylinder.

Instead of pulling the plug leads off why not just use a screw driver to short out the plugs one at a time. (That is if there is no insulating cap on the plug.) Just link the plug wire to the head with the shaft of the screw driver.

[Bruce Parker (RIP)]

Y'know that feeling you get when the zap goes right up to your armpit? I'm getting it now just talking about mucking with the spark...and I'm nowhere near an engine.

Careful as you are and with due regard for proper electrical insulation you just KNOW you're going to get zapped when you do stuff like this.

[Tony Smith]

Originally Posted by rob love

Now for the shocking part.

These jobs are much easier with a second person.

It's what you're NOT saying here is the important part.

If your Ignition Leads are in less than optimal condition (especially the rubber or plastic insulation that fits on to the tip of the plugs, although the leads themselves can be leaky), then pulling them off and pushing them back on while the engine is running can give you a bit of a HT shock (don't worry, while it's 40,000 volts, it's very low amperage ). That can make it difficult to hear if the engine revs have changed as you're waving your arm around shouting "Holy Mother of a Cow!"

Having a second person do the job is not always easier, as the involuntary muscular reflex of the electrical impulse can see them thump you in the side of the head, often some time later when the job is finished and you're having a

[Bruce Parker (RIP)]

Originally Posted by Tony Smith

It's what you're NOT saying here is the important part.

If your Ignition Leads are in less than optimal condition (especially the rubber or plastic insulation that fits on to the tip of the plugs, although the leads themselves can be leaky), then pulling them off and pushing them back on while the engine is running can give you a bit of a HT shock (don't worry, while it's 40,000 volts, it's very low amperage ). That can make it difficult to hear if the engine revs have changed as you're waving your arm around shouting "Holy Mother of a Cow!"

Having a second person do the job is not always easier, as the involuntary muscular reflex of the electrical impulse can see them thump you in the side of the head, often some time later when the job is finished and you're having a

I think if you have your #2 work the plugs and #2 gets the inevitable zap then a plonk on the side of your head would be the correct and expected thing your #2 would do to you. Once they got feeling back in their arm that is.

I've asked my wife to help me bleed hydraulics and hit the starter button from time to time but I'm not thinking making her my #2 go-to person for spark plug work is a good idea.

[rob love]

I meant that the other person would be to crank the engine, or to feel the exhaust for the miss. If I ever had the missus pull the plug wires and get zapped, well, I can't say for sure what would happen. I know it would not be a good thing to laugh at.



My own rule was that whomever's vehicle it was had the job at the sparkplug wires when trying to find a bad plug. When I was in the service, the old 5/4 ton chevs got a new system of shielded plugs and wires. There were a lot of failures early on, and rather than rip out everything and install 8 new wires and insulators, I would have the operator pull each wire one at a time while I felt the exhaust. I was attached to an infantry unit at the time, and some of those guys were pretty tough. But they all said ooookkkkkay the same when a spark plug wire was pulled. I would say OK if I felt a new miss and they would put the wire back in. If I could not quite discern the miss, I woudl say "do it again" and they would pull that wire out again, and say ooookkkkay? I would find the bad wire and unsulator, and have them back on the road (a little worse for wear) within a half hour vs the several hours to tailor the wire set and replace all the insulators in the shields for the plugs.

[Ron Pier]

The screwdriver to earth method is the easiest if there are no plug caps. Otherwise I disconnect all the plug caps and just rest them on the plugs. Then with some insulated pliers, lift each one in turn away from the plug. You can also hear the clicking of the spark which confirms that the lead and ignition is ok, and if the engine note changes when the cap is lifted clear, you can assume that plug is ok. Ron

[Richard Farrant]

Personally, I would approach this in a different way, remove plugs one by one noting if any particular plugs (and cylinders) are oily, this will give a positive indication as to where the problem is.

[Lynn Eades]

In the old days, getting the spark to jump a 1/4" inch gap was your lucky day, and shorting out the plug was no big deal. Any "man" could handle it!
Things have improved a bit and now the spark will jump about 3/4" (for the metric thinking, that may as well be a meter)
The idea of shorting these ignitions out with a screw driver sends a wee shiver (induced current?) up the spine of any life loving mechanic, at the preliminary thought / idea of shorting a plug out, and makes him /her (plus 20 other pronouns) wonder how much truth there is in those warning stickers about the dangers of meddling with these voodoo boxes.
Btw, for the newbies; stick the sharp end of the screwdriver hard to the head (earth point) BEFORE introducing the spark plug lead to the shank. This generates more job satisfaction, for you. If you do it the other way around, it generates job satisfaction for other people.

[RichardT10829]

Hi Barry, you say it’s smoking, is running lumpy too, or does it have a smooth idle but happens to be smoking a whole bunch ?