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| Possibly not running on all 6 cylinders. Will a temperature reading work? (Page 3/6) |
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buddycraigg
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MAR 22, 05:10 PM
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| quote | Originally posted by Cliff Pennock:
But I tried that once and even though I was wearing rubber gloves, got shocked pretty bad. Not doing that again. |
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Ya big baby.
It's only 40,000 volts.
You can have the plug spark, but the cylinder could still not fire because of a fuel injector, or lack of compression, or the plug could be shorted with a buildup of carbon.
Google "plastic spark plug pliers"
See if anything comes up locally for you.
They're cheap.
I guess even metal plyers with a wire connected to it and then attached to metal on the engine would work too.
(very small probability that you would be the path of least resistance, but I'm not making any promises)[This message has been edited by buddycraigg (edited 03-22-2024).]
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Patrick
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MAR 22, 06:57 PM
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Geez guys, this isn't rocket science. 
Attach a copper wire (ie 2 ft length of house wiring) at one end to the block, and the other end to the metal shaft of a screwdriver with a plastic handle. With all six of the rubber boots (one for each cylinder) pulled up clear of the distributor, stick the tip of the screwdriver into the top of each spark plug wire tower on the distributor cap while the engine is running. The high voltage will want to find the path of least resistance to ground, and that'll be to the metal tip of the screwdriver and then down the wire to the block. Just make sure to hold the end of handle farthest away from the metal shaft. Easy peasy. No pulling of spark plug wires is required, and no chance of frying the coil.[This message has been edited by Patrick (edited 03-22-2024).]
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Stingray92
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MAR 22, 07:26 PM
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Playing around with electricity is no joke! If you're gonna try visual spark check method at least ensure you got some decent insulating device between you and the plug.
As the starting part of thus thread stated you believe that not all cylinders are firing, aka you need to look for hot exhaust at the manifold port. The exhaust manifold will get very warm quickly upon start/running. Could be bad fuel injector, fouled plug, etc. How you choose to verify what your engine is doing from here is up to you.
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Cliff Pennock
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MAR 22, 08:00 PM
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| quote | Originally posted by Patrick:
Geez guys, this isn't rocket science.
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So if I understand correctly, you want me to in fact short the outputs of the distributor to ground one by one. If the RPM goes down, that plug has spark. If the RPM doesn't go down, that plug doesn't spark.
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Patrick
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MAR 22, 08:15 PM
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| quote | Originally posted by Cliff Pennock:
So if I understand correctly, you want me to in fact short the outputs of the distributor to ground one by one.
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Correct.
| quote | Originally posted by Cliff Pennock:
If the RPM goes down, that plug has spark. If the RPM doesn't go down, that plug doesn't spark.
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You're still not quite getting it. Buddy understands...
| quote | Originally posted by buddycraigg:
You can have the plug spark, but the cylinder could still not fire because of a fuel injector, or lack of compression, or the plug could be shorted with a buildup of carbon.
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Cliff, you're just trying to find which cylinder isn't working... whether that be due to lack of spark, carboned up plug, no compression and/or no fuel. When you short out the spark to a cylinder and it makes no difference with the RPM, then you need to figure out what the problem is with that cylinder. Right now, you're just trying to find which one (or more) it is![This message has been edited by Patrick (edited 03-22-2024).]
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Cliff Pennock
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MAR 23, 04:02 AM
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| quote | Originally posted by Patrick:
You're still not quite getting it. Buddy understands...
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No, I understand quite well. I think you're not understanding what it is I'm trying to do. I'm trying to find out if the engine is running on all 6 or not. Nothing more, nothing less. That's the first thing I want to know. And the test you described will tell me that. For now, I don't care (yet) what the possible cause could be if the engine isn't running on all 6. Like I said, I first need to know if the apparent drop in performance and the sound the engine makes is indeed caused by the engine not running on all six cylinders.
So in short, I'm not trying to find out if a plug sparks (because like you both said yourself, that is no guarantee the cylinder fires), I'm trying to shut off one cylinder at a time while the engine is running to easily hear if it makes a difference or not. So engine running, I short one of the cables. RPM drops, then that cylinders is firing. If it doesn't drop, then I have found the problem cylinder. I can then troubleshoot what actually is wrong (spark plug, injector, compression, etc).
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Cliff, you're just trying to find which cylinder isn't working... whether that be due to lack of spark, carboned up plug, no compression and/or no fuel. When you short out the spark to a cylinder and it makes no difference with the RPM, then you need to figure out what the problem is with that cylinder. Right now, you're just trying to find which one (or more) it is!
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Exactly. That's why I initially asked if taking a temperature reading works. The spark tester was just an inquiry if these things actually work (in case I do find a non working cylinder, so I can rule out a spark plug problem) since I read many contradicting reviews. Some say they don't work at all, others say they work perfectly.
So I'm guessing because of this second discussion about spark testers (which is really a reply to TheOgre's advise that if I want to test spark, I need one of these), you are under the (false) impression I only want to know if a cylinder sparks or not.
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jelly2m8
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MAR 23, 04:33 AM
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Oh for fuksakes don't be a pussy, your not gonna fry the coil or anything. this is a 80's GM Do or die ignition system. put a heavy glove on, welding gloves work great. pull a wire off the Distributor with it running , when you did all 6, the one that did not make it worse, there is where you look..................
Everyone is replying like this is something exotic and Spooky, NO it's GM. pull a damn wire and see what happens.[This message has been edited by jelly2m8 (edited 03-23-2024).]
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jelly2m8
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MAR 23, 04:41 AM
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Fiero/ GM injectors of that era are pretty damm reliable, High chance you have a bad plug wire. [This message has been edited by jelly2m8 (edited 03-23-2024).]
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buddycraigg
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MAR 23, 04:52 AM
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I'm waiting with bated breath, to hear what you find out.
BUT...
I have a story.
I had a V6 car, 85 maybe 86
Very underpowered, bur still seemed to run *smooth* by my opinion.
one of the fuel injector fuses was blown.
1,3,5, and 2,4,6 are on separate circuits.
It mystified me that I couldn't feel a misfire.
The 2.8 is just so perfectly balanced.
| quote | Originally posted by Cliff Pennock:
So I'm guessing because of this second discussion about spark testers (which is really a reply to TheOgre's advise that if I want to test spark, I need one of these), you are under the (false) impression I only want to know if a cylinder sparks or not. |
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The spark tester thingies really only give you 1/3 of the story. and are almost useless.
I would GIVE you the ones I have, but would cost more in shipping than what they are worth.
| quote | Originally posted by jelly2m8:
Oh for fuksakes .... |
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I don't know that I can put it as eloquent as you.
But you are right.
The GM HEI system would make Storm from the X-MEN proud.[This message has been edited by buddycraigg (edited 03-23-2024).]
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Cliff Pennock
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MAR 23, 07:28 AM
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| quote | Originally posted by jelly2m8:
Everyone is replying like this is something exotic and Spooky, NO it's GM. pull a damn wire and see what happens.
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I did that once. With rubber working gloves. Got shocked badly. Having a heart condition, I'm not going to "pull a damn wire and see what happens".
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