Cylinder balance

[SilverSHO]

When I checked codes a couple days ago, I ran the cylinder balance test, and EEC revealed that #1 and #3 are weak. A few weeks ago, when I replaced the copper Motorcraft plugs with the double platinum ones, I found that the #1 and #3 plugs looked horrible (the ones in the motor, not the new ones). The #1 plug was caked with carbon (i.e., the gap was almost bridged), and part of the #3 plug was burnt off (the hook-shaped piece on the plug's bottom end; can't remember the name of it). The other four plugs showed normal signs of wear. What could be causing problems in these two cylinders to ruin the plugs like that?

I know I don't give much information, but right now all I know is that there's a problem in cylinders 1 and 3; I don't have a compression tester handy, or I definitely would have checked that.

 

[luigisho]

Is there a reason why you are using copper plugs? Are you running boost?

 

[sho_dwn]

Do you have excessive oil in #1 and #3 plug wells? That can ruin your plug wires causing that particular spark plug to misfire. Just a thought. My friend ran into a similar problem with his 91 and the plug well seal for his #5 cylinder (if I remember correctly) was leaking. He had a slight misfire that you almost couldn't tell was there, but when we changed his plugs it was apparent that it was misfiring.
Alan

 

[SilverSHO]

Nope, no boost. Autozone didn't have the double plats in stock the day I went to get plugs, but they had the copper ones, and I didn't want to wait (old plugs HAD to come out...they were the Autolite APP3924s).

I've never seen any oil in any of the plug wells. I may just be lucky, but I cleaned out all six wells before I changed the plugs and there was no oil in any of them. I'm thinking my wires are a little fruity also; I'd like to replace them when I get the chance.

 

[luigisho]

I agree. I think you should put oem plugs and wires in and see if that makes the difference. Get them from fordpartsnetwork.com

 

[SilverSHO]

I've got the OEM plugs; now I just need to scrape together the $84 for the wires. I get paid next week, so it's all good

 

[twr]

I can't remember if the #1 and #3 cylinders share the same coil pack - but if the do - there's your problem.
Terry

 

[luigisho]

I don't think they do. I think 1-3 share coils w/4-6.

 

[stevetatro]

Whoa. What's this about sharing coil packs?

I need somebody to explain to me how the coil pack works, I suppose! All I know is I replaced mine because it went bad!!!

Thanks for any info.

 

[luigisho]

The coil pack contains 3 coils which are responsible for 2cyl. each.