Spark Plug Wire Replacement??

There was a time I did all my own work on my vehicles, but no more, except for simple things, such as oil and plugs and a bunch of other stuff. I recently had my front brake rotors replaced, and they said it runs rough at idle, and I should replace plug wires and rotor cap. I just put new plugs in less than 2,000 miles ago. Yesterday, I picked up the car from having the timing belt replaced, and on the receipt they said Vehicle needs cap, rotor, PCV & plug wires.

Many years ago I had a pickup that was running rough, and I could not for the life of me figure it out, when one night driving home on a dark road, I pulled over, opened the hood, and the plug wires were putting on a light show. I replaced them. End of problem.

So, rather than spend huge amounts of money for labor to have them replace the plug wires and so on, I waited till it got dark, started the car, and looked under the hood. Nothing. Pitch black. No arcing anywhere. Could the problem still be plug wires and rotor cap? The only sign that anything is wrong is that it is rough when idling. Once you give it gas, it runs like a champ.

The car has about 140,000 miles on it.

 

If those are the original plug wires they are about due for replacement as well as the cap and rotor. That is no more than regular maintenance and you'd probably recover the cost in increased fuel mileage.

The PVC valve can also be cause of what you're experiencing. They are fairly cheap and easy to replace. I would do that also.

The external leakage (arcing) you saw the other time you had the problem is one way a plug wire can fail. The can also break and deteriorate internally. They typically have a resistance value stamped on the wire. That usually is a per foot resistance value and can be checked with an ohm meter to determine serviceability.

A cap and rotor would only show visible signs of faults if removed and inspected.

If you have done some service work on your vehicles you shouldn't have any problem DIYing the part replacement. I would change the cap, wires, and rotor myself. Mark everything with tape to make sure you got it back on in the right place.

Hope this helps,

Bob

 

Thanks. That does help. When I took it in for the front brake rotor replacement, they told me those things plus spark plugs should be replaced. When I told them the plugs had well under 2,000 miles on them, they seemed surprised, so I was wondering if they tested anything, or were just randomly telling me I needed to replace this stuff cause they thought it should be done, and wanted more of my money. This is the kind of work I’d prefer to do myself. Much cheaper than having it done. So, I’ll head for the local Napa store, and pick up a PVC valve and some plug wires, and see if that helps. If that doesn’t cure the problem, I’ll replace the cap and rotor.

 

When they saw the original wires, they probably assumed the plugs were also original

If the cap and rotor are original. I'd suggest replacing them also

These parts are 'consumable', and not meant to be replaced only when 'broken', but as part of regular maint.
They gradually reduce effectiveness (on a few different levels with computer controlled engines) until they wear out or break
You want to replace them before they start losing effectiveness (and start affecting-and creating undue wear on other engine processes), not wait until they 'break'

 

Point taken. I will replace all these items. Is there anything else that might be considered routine maintenance that I might consider also?

I drive so little these days, that I rarely even think about maintenance. Probably 4,000 to 6,000 miles a year between two vehicles.

 

Belts and hoses. Even though you don't drive much they will dry rot and break/burst on you at the worst time.

 

Fuel Filter
Lack of use can actually create more gunk in the fuel system
Clogged (partially) fuel filter could cause rough idle

 

That's good advice, tho I've never had a belt break on me that I can recall. I knew all belts would have to come off to replace the timing belt, and tho I thought about having them replace all belts while they were replacing the timing belt, I spaced it out till after I picked up the car.

Hoses... Never even thought of them. I'll take a look at them.

Well, I know that’s never been replaced, so I'll put that on a to do list. I’ll have to find out where it is located, and see if it's something I can do.

 

Here is what I did today. Bought new PVC valve, plug wires, distributer cap, and rotor cap. Had to take the air filter off to get at the PVC valve. The air filter was crud, so went back to parts store, and picked up a new air filter. Got those two things installed. Started it up, and it still ran rough, but definitely smoother. Not sure whether the PVC valve or the air filter made the difference.

The distributer cap is held on by two phillips head screws, and there is one screw in the distributer cap that I can not get loose. I sprayed WD-40 on the screw, and let sit for a couple of hours, and still no go. Even tried a pair of vice grips, but still couldn’t loosen it, so the old distributer cap and rotor will have to wait till I can figure out how I can get that screw out. I did replace the spark plug wires, and that definitely made a difference. The car idles smooth now, and even starts easier, tho it has always been an easy starting car. Guess the mechanic was giving me good advice, but I just couldn’t see paying someone todays outrageous labor costs to do something so simple. The timing belt was only $48, but labor for installing it was $182, but that was something I couldn’t do myself.

Thanks for the tips and advice. Very much appreciated. If anyone can give me some advice as to how to loosen that screw in the distributer cap, I could us some tips.

 

Hopefully you have not began to strip out the phillips. If not, be sure you only use a screwdriver bit that fits snugly inside it. I have found various pop-in type bits (the kind that go in 6-way screwdrivers and cordless drill atachements) whose 'pitch' of the phillips is different. You want either one of those screwdrivers that has a big handle, like those kind they invented with a big ball for a handle, or a real long screw driver (must be 16 inches long or so). Both deliver tremendous torque, and often can snap lose even a rusty screw.

Oh - I was able to undo my next door neighbors rusted distributor cap screw with one. He too had one that came out, not very rusty, and the other one was real rusty.

 

Well, the slots in the screw head are beginning to become rounded. Enough so that it will only get worse if I try more. I don’t have a big phillips head screwdriver like you’re talking about. Short of drilling it out, which I really don’t want to do, cause I always seem to screw that up somehow, and make a bigger mess, I just may have to take it somewhere to have that one stinking screw loosened for me. It’s cases like this where an old fashioned slotted screw would be easier to get out than a phillips head screw.

I took it for a test drive yesterday, and there is still a slight roughness to the engine at idle, not nearly what it was, so I really want to get that distributer cap off, so I can replace it.

 

Spray some liquid wrench or WD-40 on the thread area of the screw, set your screwdriver in the screw and give it a few good smacks with a hammer, the liquid wrench and wd40 need the viabrations to start working and the smacking can breal loose any corosion. Have a good one. Geo

 

You mentioned that you didn't have a screwdriver like that. In cases where $4 is cheaper than a mechanics bill, you may want to go out and buy one! Same with Dremel (or like) tools that can bail you out where, say, in your case, if a cutting head can get in there, you can actually cut a slot across the phillips and use a flat screwdriver.

Trouble is with penetrating fluids in your case is the head of the screw is sitting tightly down on the plastic of the cap, and it likely wouldn't be able to flow down into the threads.

 

Well, the WD-40 wouldn’t penetrate down to the screw. Banging on it did nothing, so I drilled the head of the screw off so I could get the distributer cap off and remove the screw. WD-40 and banging on the screw did nothing. Vice grips just slid around the screw. I could not get in there with a Dremel to cut a slot in the screw, but I could get in there after I got the distributer cap off, so I cut a slot in what was remaining of the screw to see if I could use a screwdriver on it. Everything I tried failed, so I ended up taking it to a mechanic. He said a steel screw in an aluminum housing probably caused electrolysis, and he wasn’t sure he could get it out, and I might be looking at a new distributer. He was able to get it out. It wasn’t easy. It was a struggle.

In this heavy salt environment the car has been in all it’s life, I’m probably lucky electrolysis didn’t claim the distributer. Wouldn’t a designer know better?

I took some photos the other day, but just never had time to log on and post back to this thread, but since I took them, I might as well post them. Red arrow points to the frozen screw.

Distributer Cap Still On

Distributer Cap Off