I replaced the plugs and wires in my '93 Aerostar 4.0L about 3-4 weeks ago. I then tightened the lower intake manifold. I still have a misfire.

I placed a small mirror taped on a magnetic pick-up tool at each plug because I thought I heard a snapping sound. There it was, the spark at #5 is traveling around the center of the plug and short grounding to the outside of the plug.

If I bent the connector to the plug, can it be adjusted to fit correctly?

Will di-electric grease help?

Should I return the one wire to the store?

Dativer

 

Oh, dielectric grease may help. I've never had this problem. Did you use dielectric grease on all the plugs. You're supposed to. If that doesn't do it then I'd just take the wires back.

 

What if I put dielectric grease on the contact? Would that increase the resistance enough to divert the spark around the plug?

 

I did use dielectric on all the wires. I may have used it on the contact of #5 wire also.

 

What solvent would clean off the dielectric from the contact?

Dativer

 

I bet denatured alcohol would clean that stuff off. I've never used the grease on the wires themselves. Put it on all the contacts. Good luck man. Hope it works for you.

If it doesn't, I wouldn't waste the time screwin around with them. Rip those wires off and head back to the store you got them from. Let them replace those wires with new ones. I doubt they'd take back only one wire. They'd most likely want all of them to exchange them. What wires are you using? Don't skimp on plug wires, but don't buy race wires for a daily driver. You won't notice the performance for you shelled out a whole lot more for. Do buy good wires. They'll be on for a long time before you replace them again and they need to hold up. I hope I've helped you. Let me know how it goes.

 

(Embarressed) I did buy inexpensive wires. I didn't think I could fix this missing problem and I am getting pressure from my partner, "not to throw any more money into that thing".
She is willing to forgo any car for the winter.
I love to solve mysteries.

Wires weren't that bad to install. Now the plugs on the other hand...

What do you think of electronic contact cleaner or intake cleaner? I have both. I will need to buy more dielectric, though.

Dativer

 

Contact cleaner would probably do it, but you probably don't have to clean it. It's not that critical. Yeah, those plugs can be a bear to put in. Did you have to take off the tire and the inner fender skirt to change the plugs? Sometimes I think it'd just be easier to pull out the whole motor and get the plugs done in no time.

Those wires are probably okay if they are working on the other plugs. Buy what you can afford, but don't buy more than what you need. A daily driver doesn't need a set of $100 plug wires. Vehicles are expensive. We all know that and a few dollars here and there for this and that really can add up quickly.

Before you spend anymore money, try this. Make sure the plug wire isn't dirty inside. You'd be surprised how little specks of dirt can get into tight places and cause things not to fit right. Use a Q-tip to clean the inside just to make sure. Then pop the wire back on and make sure it's on all the way. Maybe the wire didn't pop on all the way the first time. I've never had defective plug wires so your's are probably okay and maybe it just didn't fit on there right the first time. Sometimes you have to press and twist a bit to get those wires on all the way. This can be tricky when you don't really have much room to work with and you can't really see what you are doing.

Let me know if this works. If it doesn't work you can check to see if the wire really is bad by pulling a wire off from the other plug and cap and then swap wires to see if the same thing happens again.

Hope this works for you.

 

I removed all the wires completely, one at a time. I sprayed contact cleaner on both ends, cleaning the copper connections. I then sprayed each plug, to clean off the connection end. I placed dielectric on the ceramic of each plug and on the edge of each boot and on each coil boot. Replacing the wires.

One of the boots had a small crack from the edge in towards the wire. I put extra dielectric on the boot and onto the ceramic of the plug.

TADA! No more arcing.

Thank you, Pipercub, Rockledge, MrShorty, and Racerguy.

Only Mac owners are equal to the tireless help you provide to total strangers in need.

Thanks alot again. If I can ever repay you, just ask.

DATIVER, Valley Forge Area

 

Glad you got it to work right! Now you'll be an expert at it when it comes time for you to do them again sometime.

 

Good job on the fix.