Why Did my plugs foul out already?!

TheScaryGuy · July 30, 2002

Okay, I started getting a misfire today, come to find out the bosches that maybe have 8000 miles on them are fouled out bad!!! Wtf? I read on turbobuick forums that those guys have had problems with them fouling out also. I guess I don't uunderstand why they would go bad so quickly. If they were AC's I wouldn't care but these suckers were 4 bucks a pop! Any possible explaninations for this? I don't have a clue.

Recent work - cap, rotor, wires(when I did plugs) all within the last year. I don't put but maybe 10,000 miles on my truck a year.

carguru · July 30, 2002

Gee, Scary, you are just having all kinds of problems. ??? Are you burning any oil? Any other symptoms? When does the misfire occur?

bassdog · July 30, 2002

Scary-

I just pulled mine yesterday to check and regap them. They maybe have 8000 miles on them and they didn't look too pretty ??? . I too have replaced the cap, rotor and wires at the time of the plugs.

I'll be replacing mine with regular AC's this time. Have you checked your timing lately? I may have an engine carbon clean performed soon...

mnstrmdnss · July 30, 2002

i have +4's in my sonoma, they have about 20,000 miles on them and are still like new. i dont see how these plugs can foul out, anyway.

CMNTMXR81 · July 30, 2002

Part of it has to do with the four spark kernals. Split Fire's with their split fork electrode are also prone to misfires.

Basically the spark being generated by the center (core) electrode of the plug is being distributed 4 different ways in your case. This means the flame kernal isn't as strong as a single concentrated spark and therefore is prone to being blown out by the compression of that cylinder. Having unburned fuel in the cylinder helps contribute and soaks the electrode of the plug so that it doesn't fire at all eventually. Another problem associated with Split Fire's and +4's is that with multiple sparks being created, each ignite the A/F mixture at different speed and timing due to the strength and random firing across the electrode. This could result in "pinging" as the two flame fronts collide. Possibly resulting in knock retard.

Also, these style plugs because of their additional individual spark kernals tend to add more resistance needed to fire the plug and having a wet/fouled tip adds even more to that resistance. Simple electricity 101 says that the electricity will take the shortest path to a ground. That shortest path is the next weakest part in your ignition system. It could be a plug wire, it could be a coil. With an HEI system, that will fry something REAL quick.

I've seen this dozens of times especially on HEI systems on GM fwd vehicles where someone installs Split Fire's, Bosch +4's or even regular Bosch Platinums. They simply don't fire or create so much resistance to fire (the Bosch platinum) that the electricity goes elsewhere. Usually the wires are the weak link and I've had to pull off sets of wires that were fried to a crisp. So fried that even the outside rubber coating was stiff and brittle. These HEI systems are VERY tempermental when you unbalance them by putting such a plug in.

To sum it up, the best plug out there for performance needs is a softer conductive metal like gold or copper and one that funnels all it's energy into one STRONG spark kernal. AC Rapidfires and NGK's are good at this. (platinum is a hard metal which resists firing and therefore lasts much longer resulting in plugs that will go 100,000 miles) Not only will the stronger spark from a plug like AC Rapidfire or NGK's create a bigger bang in the combustion chamber, but it reduces the chances of being blown out as well as not having multiple flame fronts caused by other sparking.

SilveradoWV · July 30, 2002

Hmmm? I have the 99 cent Bosch copper plugs in the '91 K1500 and they have been in there for a while, and still seem to be doing good, other than a rough idle, which might have been helped out by changing the Dist. cap and rotor the other day! Seems like it eats caps, this one lasted 20,000 miles and I have had some last as little as a week or 2! This one was unusual becasue all of the outer tips werent that bad, but the center one looked burnt and wore alot!

TheScaryGuy · July 30, 2002

Gee, Scary, you are just having all kinds of problems

Most of those are mental though.

Are you burning any oil? Any other symptoms? When does the misfire occur?

Misfire was on 3. They were all shot to *hit. I burn about 1/4 of a quart in 2000 miles or so.

I've seen this dozens of times especially on HEI systems on GM fwd vehicles where someone installs Split Fire's, Bosch +4's or even regular Bosch Platinums. They simply don't fire or create so much resistance to fire (the Bosch platinum) that the electricity goes elsewhere. Usually the wires are the weak link and I've had to pull off sets of wires that were fried to a crisp. So fried that even the outside rubber coating was stiff and brittle. These HEI systems are VERY tempermental when you unbalance them by putting such a plug in.

I now realize I need to take my plugswires back. Warranty should cover the fact taht they are burned up(worst is 3, burnt to a chrisp like cmt said). I wish I would have known this beforehand. Thank you CMT. So basicly, weak plug wires + saturated plugs that can't burn off access fuel = Wasted Money? Least I have brakes now. Just can't go anywhere......lol......I might as well give up being pissed off..lol

carguru · July 30, 2002

Hope the store give you the right parts this time.

TheScaryGuy · July 31, 2002

Hope the store give you the right parts this time.

I went and got the part number!

lol

CanadianZ71 · July 31, 2002

Quote from CMNTMXR81 "Another problem associated with Split Fire's and +4's is that with multiple sparks being created, each ignite the A/F mixture at different speed and timing due to the strength and random firing across the electrode."

CMNTMXR81, not to be argumentative but you've got the theory behind these plugs entirly wrong. There is no multiple spark - just one spark that chooses the 'path of least resistance' and has four electrodes to choose from. You cannot split a spark but to obtain the best spark you want to provide the path of least resistance and with four electrodes you provide four equally favourable choices. I don't know where you would have ever got the idea of multiple sparks.

TheScaryGuy · July 31, 2002

Another thing, I believe these plugs were just way to hot for my motor now that I think about it. On #3 one of the electrodes was partially burnt away. They rest were ghost white. So I guess I'll stick to ac's.

July 31, 2002

Ive found that buying expensive plugs is a waste of time. AC-Delco works just fine. Especially for your year of truck. Im not certain but I think mine are NGKs... I havent looked... But i know that when I have to replace them, the exact same plugs are going back in...

CMNTMXR81 · August 1, 2002

Quote from CMNTMXR81 "Another problem associated with Split Fire's and +4's is that with multiple sparks being created, each ignite the A/F mixture at different speed and timing due to the strength and random firing across the electrode."

CMNTMXR81, not to be argumentative but you've got the theory behind these plugs entirly wrong. There is no multiple spark - just one spark that chooses the 'path of least resistance' and has four electrodes to choose from. You cannot split a spark but to obtain the best spark you want to provide the path of least resistance and with four electrodes you provide four equally favourable choices. I don't know where you would have ever got the idea of multiple sparks.

That's exactly what I meant though. You're relying on the plug splitting that spark evenly and at the same speed over 2 or 4 electrodes which doesn't always happen.

In a simple case, let's use a Split Fire plug (which I have used BTW), while they seem to be a pretty trick plug, I found that when the plug would fire, the spark didn't split to each prong of the electrode with exactly the same amount of energy on each split at exactly the same time. What happened would be on one firing, one of the two electrodes would get all the spark, the next firing, both electrodes would get it by splitting, but the spark wasn't as strong and concentrated, the next firing, one side of the electrode would get spark then it'd split and go to the second prong, and it'd repeat this process in varying sequence as long as electricity was delivered to it.

This led to two problems. 1) Spark that was split between the two electrodes wasn't as strong/concentrated, therefore was suceptible to being blown out by the winds of compression. And 2) when the spark would stay lit across both prongs, one split of the spark would light the air/fuel mixture around it and then the second one would light the a/f mixture around it. What this led to is two flame fronts that at some point in time have to connect. When they do this, you get a "bang" I.E. "Pinging," "dieseling," "detonation," etc, etc. As you know, on our vehicles, knock sensors in the valley pick up this detonation and scale back timing until the "pinging" stops.

Now you're splitting the spark 4 ways on the Bosch +4's which only compounds the problem.

The best solution is ONE strong, concentrated spark generated from a softer, more conductive metal (other that platinum or titanium) for performance needs.

If you are concerned about longevity, that's another story. A platinum/titanium metal which resists firing due to their higher resistance is your ticket. Due to their firing resistance is the reason they last 100,000 miles. Conversly, the spark kernal generated across the gap is nowhere near as strong and concentrated as that of the softer metal plug.

I was simply using two sparks as an illustrative purpose. So until you can prove that Split Fire's split the spark evenly and at the same speed across both electrodes EVERY firing and the Bosch +4's do the same across their 4 electrodes EVERY firing, I stand by my thesis.

mnstrmdnss · August 4, 2002

the whole concept about what your talking about is very believable, cmntmxr81, but i have a much better experience with the +4's. i put them in my plymouth breeze when they first come out and made a big improvent in idle quality and when you let off the clutch to accelerate, the car didnt bog at all compared to the old plugs(the "old" plugs were the original plugs and only had 25,000 miles on them cause the car new at the time), then when i got rid of that car, i got my gmc sonoma, with about 30,000 miles, and through in a new set in there, and again, big improvement in idle and acceleration. maybe its due to the fact that these cars use dis ignitions(no distribitor), maybe this makes a difference compared to distributor equipped engines?, but anyway, i love them and they work awsome for my application.