First Post-Spark Plug Extenders Arcing

I bought an '87 328 about 5 years ago, have had absolutely no problems and have only changed the oil/filter every 6 months and the air filter once.
The engine now has about 28,000 miles on it. It was running fine one day and the next day it was missing.
Took it to a mechanic here in Ft Worth and found an extender on the backside bank was arcing where the clip on the extender connects to the plug. Taped over the burnt spot with electrical tape till I could replace the extender and the engine ran smooth. Before I got several miles from the shop, it started missing again. Got home and found another extender arcing at the same spot and was also on the backside bank of cylinders. I taped that one and examined the other extenders and didn't find any other extenders with burnt spots. Took the car for a short drive the next day and it ran fine for about 15 miles and then started missing again.
Examined the extenders again and found another one was arcing at the same spot even though it didn't have a burnt spot when I checked it before. I taped over the burnt spot and the car ran fine, no miss. So, I taped over all the other extenders and ordered a set of new extenders. I am waiting for the extenders.
Question--I am skeptical of coincidences(3 extenders arcing within 20 miles of each other) and therefore, am worried that something else is wrong.
Can anyone give me any input regarding this problem? Could there be another problem that would cause the extenders to start arcing other than the extenders going bad all at once?
I find it strange that all 3 of these extenders that arced are on the backside bank?
I appreciate any input.
Thanks,
Dennis

 

Bad extenders are a common problem with the 3x8 series cars. Your replacements should solve the problem.

 

five years is about full use for all the extenders, plugs and wires.... in fact you're just about due for a major service if it's been 5 years since your last one.

 

totally, 100% completely normal. They ALL will go at some point. Just buy a new set and you'll be good to go for the next decade or so.

 

Wow 5 years , mine are original. In fact they are the type that you need to screw the spark plug wire into a stud in order to attach it. I guess I'll be replacing them soon. HAHAHA.

 

Doesn't the fact that one, then a second then a third failed possibly point to something causing the failures? I'm not a tech but common sense would tell me this isn't a coincidence as was the original poster's concerns. He stated the rear bank was where the first two failed, not sure about the third. If all rear bank could it be a bad coil or rotor or other electrical issue? I'm assuming one failing isn't going to make other extenders fail.

From the mechanics I've talked to you should get 10 years out of them.

Good luck, I know the ignition/electrical problems can be difficult to figure out some times.

Jeff

 

My extenders are at least 8 years old and in fact probably 20 years old (original). No problems.

For three to go like that in a row would indicate to me that for some reason the voltage requirement to fire your spark plugs went up significantly and the coil voltage took the path of least resistance by jumping to ground via the head rather than via the plug electrodes. Things that cause the voltage requirement to fire the plug to increase include, higher rpm's, higher compression, lean mixture, spark plug gap too big (were the plugs replaced or cleaned and gapped?), plug fouling from wrong heat range or incorrect fueling and probably some others I can't think of now.

PS. normal electrical tape is not intended for such high voltages so may not help at all.

 

Thank you guys for the input! All three extenders that arced were on the same 'backside' bank. Though I've had the car five years, I don't believe the extenders had been changed previously and I assume these are the original extenders.
I haven't driven the car since I taped up all the extenders because I figured the electrical tape isn't a good solution to the problem. But, I did go out and start up the car and let it run a few mintues yesterday evening and it ran fine.
When I get the extenders, I plan to also change the plugs and maybe ohm out the spark plug wires, though I can't see how a bad spark plug wire or wires would cause the extenders to arc.
Nothing was done/changed prior to the plugs arcing, it was just a 'fine one day, missing the next' thing, and I didn't notice any change to the engine sound, or a change to any of the operating gauges prior to the arcing.
All thoughts/opinions are greatly appreciated.
Thanks,
Dennis

 

The voltage going to the spark plugs will not be as high when idling so the problem may very well not show up then. Drive it around at higher rpm's and the problem may reappear.

 

Got to agree with the conspiracy theorists here.

Once is accidence, twice is coincidence and three times is enemy action.

Three going bad in 20 miles? Hmmmmmmmmmm……

I think something else is going on, but I would not know what to suggest. Sorry.

 

While I'm waiting for the extenders, here are a couple more 'stupid' questions, excuse my ignorance.....
(1) Spark plugs--In the 328 section where someone posted type of spark plugs, there is listed 3 types of NGK plugs identified as 'hot', 'warm' and 'OEM'...I'm leaning to the OEMs which are NGKBP7ES...are these available at PEP Boys or Autozone or do I need to special order the spark plugs?
(2) Distributor cover--Where the spark plug wires from each bank go into a cover on each side of the cam shaft(hope that's right)...how do you remove the cover to get inside? It looks like there are three 'bolts or screws' that hold the cover on the engine but the only opening is a small round hole on each of the 3 bolts/screw on the engine side of the covers and I don't see how to remove that cover? Hope that makes sense.

Thanks,
Dennis

 

Plenty of info on sparkplugs here on FChat Search is your friend.

Here are a few threads:
http://www.ferrarichat.com/forum/showthread.php?t=166839
http://www.ferrarichat.com/forum/showthread.php?t=162345
http://www.ferrarichat.com/forum/showthread.php?t=168456
http://www.ferrarichat.com/forum/showthread.php?t=182577

PS I went with Iridium's in my 308QV. Pep boys had them at 6.99 each, cheaper than online.

You can go to http://www.sparkplugs.com/ to search for the appropriate plugs and order online. Thats a great website.

On my QV, the distributor cover "bolts" had both a head bolt and a slot for a screw driver (from memory) and they are a pain to get to. But yes, you unscrew these bolts and EACH distributor cap comes off. On the inside of the distr cap, you will see where each plug wire is connected and the coil wire. There are small brass screws that hold in each wire. This screw is pointed so that when tightened, it goes thru the insultion to connect with the core.

2 Points of ADVICE:
1) REPLACE ONE AT A TIME so you dont mess up the firing order. And for that matter, one side at a time.
2) Do NOT force the little brass screws, make sure your screwdriver is the correct size for the slot, even if you have to buy a miniature screwdriver set to match it best.
My time for replacing the wires/sparkplugs was 6.5 hours, but admittedly, I'm not a mechanic.

James in Denver

PS I knew I should have taken pictures and posted a "how to" thread.

 

Thanks for the information!
I guess what I was asking about is the boot cover on the distributor cap...from the diagrams at Ricambi, the rubber boot cover on the distributor cap just pries off?

 

I wouldnt say "pry" is a good word. You sort of work it off. Its rubber and it will move so you basically move it slowly up towards all the sparkplug wires until you have enough room to get to the 3 bolts.

Many people have gotten rid of the boot cover thing on both distributor covers. However, I wanted to keep it (I guess its supposed to help keep out water?), so I left it hanging off of the whole thing as the wires and cover were removed from my car. As I replaced each wire, I ran it thru the boot. When I reinstalled, I just snapped on each wire to the correct cylinder/plug, rebolted the distributor cap on, then worked the boot back in place.

I'm not sure if the 3 bolts only allow the distributor cap to "go on" one way, but I marked one of the 3 bolts with a marker (or something? may have been whiteout stuff?) so I could remember how it reinstalled.

Hope that helps.

Maybe someone can post pictures.

James in Denver

 

Mine was wrapped with a a few zip ties. It should be no problem to simply pull it off. You shouldn't need to pry it.

The NGKBP7ES are available from Pep Boys and they should have them in stock. Make sure you check the gaps. Be sure to clean (sand or mototool) your brass contacts inside the distributor caps. Might want to scrape clean the rotor too.

As another solution I just replaced my wires and plugs and got rid of the plug extenders. I went with Taylor wires with the long boot covers and I cut my old OEM wires apart to use the old red valve cover plug caps. I never did like the plug extenders. I no longer care about concours so I'm looking for ways to make the car run better now.

 

There is a spring loaded pin fitting on my car that sits under the distributor assemblies that acts as a catch when you put the cap back on. It only fits on one way and you can sort of hear it click when you are trying to line up the caps.

 

Great information for a Ferrari novice like me.
Plus, the mechanic I am taking the car to for changing out the plugs and extenders has little experience with Ferraris.
(I just don't trust myself to even change the plugs, scared I might cross thread a plug or mess something up)

If changing the plugs and extenders doesn't solve the problem, I will send the car to a more experienced mechanic...I have been talking with a person at Norwoods in Dallas.
Thanks a lot, every piece of info helps!
Dennis

 

I'm thinking you may want to take a look at the inside of your cap and check either end of your coil wire on that side. Wires go bad. Ask me how I know? In any event, Norwood should definitely be able to fix your problem.

 

I'd really have a look at the rotor/cap on at least the bank in question. Also all connections to the coil. I'd have to think you've got a problems there. If you only change out the extenders/plugs but have a problem upstream I'd think it could cause some issues with the new parts you just installed. I would think most experienced mechanics would know what to do with inspecting and changing out these parts as needed but you'll always be better off with an experienced Ferrari mechanic of course! Piece of mind is a good thing. Good luck.

Jeff

 

Once again, thanks for all the advice and information!
We (the mechanic and I) will check the cap and rotor and coil wire on the bank in question(maybe both) in addition to changing out all the extenders and spark plugs.
I'm going to go with the NGKBP7ES plugs.
I will let you know the results. (it may be another week or so as I am waiting for the extenders to be delivered)
Thanks,
Dennis

 

BTW, here's a couple of pictures of my 'missing' baby....
It was NOT driven in the snow, just pulled it out to get a couple of pictures!...we don't have many days in Ft Worth with snow like this.
Image Unavailable, Please Login
Image Unavailable, Please Login

 

VERY VERY Nice, that chrome over black wheels in combination with the black body looks GREAT!

James in Denver

 

incredible shots!!! very cool indeed!

 

Cool shots on a cold weather