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3 Cylinder misfire after shop work on carburator
https://slantsix.org/forum/viewtopic.php?t=34936		 Page 2 of 3
Author:  NilsDavey [ Sun Apr 19, 2009 2:46 pm ]
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Hey Ted,

i've replaced the distributor, rotor, and cap with new. All leads are getting sparks.
Author:  NilsDavey [ Sun Apr 19, 2009 2:48 pm ]
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Oh just had a thought. I could probably take a video of the engine running and post it someplace. Not sure if that would help if you could see and hear it?
Author:  Aggressive Ted [ Sun Apr 19, 2009 3:49 pm ]
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IF you want to give it a try, U-Tube....

If all the cylinders are getting spark, what do your plugs look like? Are they tan colored or black and fouled out?
Author:  NilsDavey [ Sun Apr 19, 2009 4:05 pm ]
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The ones i replaced on the 4 cylinders were tan. No black or white. Slightly oily but nothing drastic.

I'll go get a video in a bit and post it up.
Author:  walpolla [ Sun Apr 19, 2009 4:08 pm ]
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hello,
I have a theory on this one.
If the engine is only firing correctly on 2 cylinders,this would happen if the firing order is correct,but the cylinders are counted from the rear of the engine. A mistake someone could make if standing at the passenger side and looking at an inline slant engine.

Counted from the rear: 1 - 2 - 3 - 4 - 5 - 6
Firing order : 1 - 5 - 3 - 6 - 2 - 4
Counted from the front: 6 - 5 - 4 - 3 - 2 - 1
(correct)
As you will see,the only 2 cylinders that would get a spark at the correct time are cylinders 1 and 3.
Nils - you are counting the cylinders from the FRONT of the engine?

regards,Rod :? :D :D

Edit: I confused myself with numbers the first time. It should have been 1 and 3 - NOT 3 and 5 like I first wrote. MOST SORRY :lol: :lol:
Author:  SlantSixDan [ Sun Apr 19, 2009 4:35 pm ]
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That's a good theory. Just to be completely clear, #1 cylinder is the frontmost, and #6 is the rearmost.
Author:  NilsDavey [ Sun Apr 19, 2009 4:43 pm ]
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I have it set up as described in the Haynes manual - 6 being closest to the firewall and 1 being at the front of the engine. The firing order described there is 1-5-3-6-2-4.

Here are the video i just took. The mike aint so great. So actually the cylinders that are firing are 2 and 5.

http://s131.photobucket.com/albums/p307 ... V10633.flv

I've got a video of me goosing the carb as well if that will help. Im going to take off for a couple of hours as this is driving me nuts. Appreciate any new ideas!
Author:  SlantSixDan [ Sun Apr 19, 2009 5:06 pm ]
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Okeh, two things:

1. Go order those three books I pointed you towards earlier in this thread. The Haynes book will not do.

2. Are you sure the distributor cap ends of the plug wires are correctly installed? If the distributor is installed correctly, #1 is at about the 4:00 position as you look down on the cap from above. Then you proceed clockwise 5-3-6-2-4.
Author:  NilsDavey [ Sun Apr 19, 2009 7:28 pm ]
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Ordered those books yesterday. And yes 1 is at the 4 o'clock position. There's a small mark on the distributor for 1 and it follows on from there.

Any more ideas?
Author:  Karasik87 [ Sun Apr 19, 2009 7:56 pm ]
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have you checked your oil level? could overfilling be a cause of this? I only ask because Jiffy lube database doesnt go back for a 74 slant six. I know this because i work for a jiffy lube. BTW, the store you went to, for what its worth, is a store that does stuff by the book. So you could at least go back and find out who did what on your car, and at least ask if they did "anything" that wasnt worth mentioning on the work order. Like nudging something out of place, and putting it back.
Author:  NilsDavey [ Sun Apr 19, 2009 7:59 pm ]
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Hey Karasik,

thanks for the response. I've checked the oil level and its just right. To be honest i think the guy a couple of posts ago was right.... they probably jogged the timing or the distributor when fiddling around. They're nice guys at jiffy lube and it was only causing the car to stall at idle. With some gas it would fire on all cylinders.

Since then with all the dicking about with the carburator and distributor its the misfiring on 4 cylinders thats the problem. This all got done at a local shop. I could take it back but they will tell me its the cylinders or heads and try and charge me $800.

This forum is great for ideas but im nearing the point of having to ditch my car as a parts or resto project and buy another car. Just gotta start saving i suppose!
Author:  SlantSixDan [ Sun Apr 19, 2009 9:38 pm ]
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As much as I like to rag on the JiffyLube jokers for incompetence, I have a hard time imagining what they could have done to cause the engine to run on only a few cylinders. I don't think they knocked the distributor anywhere, and even if they had, there is no timing adjustment that will cause the engine to run on only a few cylinders. Are you sure it's definitely only firing on certain particular cylinders, and that it's not just a very rough/choppy idle? It's difficult to tell for sure from your video, but the engine seems to start much too easily and run much too smoothly (no shake evident) to be hitting on less than 6 cylinders.

I think we may be dealing with a coincidence here. So let's resume diagnosis: How do you know all six spark plugs and all six spark plug wires are good?

We know for sure that the "mechanics" you've been talking to are no good. I'm still not clear on what kind of carburetor work the shop did. Carburetor operation and repair manuals (and some training movies) are posted here for free download.
Author:  SlantSixDan [ Sun Apr 19, 2009 9:44 pm ]
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Quote:
have you checked your oil level? could overfilling be a cause of this? I only ask because Jiffy lube database doesnt go back for a 74 slant six. I know this because i work for a jiffy lube.
Oy vey. :roll:

No, overfilled oil does not cause any of the symptoms described.
Author:  NilsDavey [ Sun Apr 19, 2009 10:59 pm ]
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Hey Dan,

i know that the spark plugs are getting spark because i checked all the wires to the block. And i know the plugs themselves are, or should be, sparking because i replaced all the faulty cylinders with new spark plugs.

I also replaced the ignition coil yesterday figuring there might be an off-chance that the problem might be there.

So to run it down again:

New distributor, rotor, cap. New spark plugs each getting spark. Engine is shaking and AT IDLE getting only 2 cylinders. Cant check it in gear as i dont have any friends in LA. Did drive it today to get some stuff though and i can report the following:

- Heavy on the gas makes the engine make a 'putt' sound
- Lots of shake at idle in gear
- Uneven exhaust

However if i really crank the gas i can get up to 60 which sounds a bit much for 2 cylinders.

Im really losing it now though. Please continue with the help! You guys are a really good resource.

EDIT: And to run the chronology:
- Jiffy lube did something to make it stall at idle
- Shop guys did something to make it fire on 2 cylinders but not stall at idle
Author:  SlantSixDan [ Sun Apr 19, 2009 11:46 pm ]
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Okeh, here's another question: Do you still have the "old" distributor?
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