mis-fire

[garrett]

I have a slight miss in my 84 t-type.I replaced two of the spark plug wires on the passenger side after developing the mis-fire. One was burnt from the up pipe flange. I re-routed the wires so that they wouldn't come in contact with the up pipe flange. I tested the third one on that side that I replaced about a month ago, and it tested really good with an ohm meter. I am using MSD superconductor wires. They have super low resistance. I had driven it two days , back and forth to work until I got a chance to replace the wires. The wires on the driver's side are older, but they have a tendence to last better because there is less heat on that side. I also tested all the coils on the 84 coil pack. I got 12.4 on two of the pairs, and 13 on the last pair. Anyways, I still have the mis-fire, although not to the same degree as before. I really notice it when I bring the car above five lbs of boost or when the alcohol spray turns on. I'm wondering, could I have fouled the plugs when I had the bad plug wire? Should I suspect the coil that reads 13 ohms? Or should I focus my attention on the older, drivers side plug wires, even though they look ok from a visual inspection? The plug wires are the easiest thing to check. I have no way to test the coil under load, only while the car is off. What type of plugs are recommended? I currently run NGK u-groove copper plugs. I'm just trying to avoid having to replace everything.

 

[Mad_Trbo]

I'll tell you what, it is cheap to replace the plugs. I chased a misfire problem for the better part of a week. My chase started with a coil that was reading higher resistance on one of the three pairs but finally ended once I replaced the plugs.

I would recommend due to the inexpensive nature of a plug replacement. The difference you note in your resistance testing is negligible. Although I would ask if you know which cylinder is causing your misfire.

 

[garrett]

I'm not sure how to find out which cylinder it is, other than pulling the plugs and looking at there color?

 

[garrett]

Can I get some recommendations on plugs from anyone? Has anybody tried the new iridium plugs, or should I use the AC delco stockers, or use what I've been using, NGK u-groove copper?

 

[onefastcar]

pull plug wires while running and you'll see which one it is just wear some leather gloves while doing this and unless you have some special goodies i'd stay with the stock delcos.

 

[garrett]

There are different AC delco plugs available. Some have a thicker electrode. Which ones are the best for turbo cars?

 

[onefastcar]

Read this whole thing it has recommended spark plugs to.


The Grand National / T-Type / Turbo Regal Buick Spring Cleaning Guide