Spark plugs for 1998 T4R LTD 3.4 v6 auto
- Thread starter Vegimate1
- Start date
19runner98
New member
When you replaced your plugs did any of you guys replace the coils too? They're $80 each so if it doesn't need to be done I'd rather not do it.
zcruiser
Senior Member
Coils rarely fail. No moving parts, no wear items. Plug wires... Eventually.
Blitzkrieg
New member
There are a lot of opinions on this subject, the most realistic being that running twin electrodes increases the spark plug life.
Twin electrode plugs require more juice than conventional plugs.
They don't "spark twice as much" like some people believe. The arc will just travel to the closest of the two grounds. Each time a plug fires a microscopic bit of metal is worn off and having two electrodes essentially gives you twice as much metal before the inevitable happens.
I just run what the people that designed the vehicle say to run and don't worry about it. ;-)
zcruiser
Senior Member
I'm not an expert, but always understood that's exactly what 'waste spark' ignition systems do. One coil, shared by 2 plugs, which fires at twice the rate. The plugs fire twice as often, the spark eating away at the electrodes twice as quickly so the plugs need dual electrodes to get the same life span as a normal plug.
TheDurk
Elite Member
You're right, but I think what Blitz there is saying is also correct. The two electrodes NEVER fire simultaneously, as some think. One or the other is the path of least resistance and carries the spark. But, as you say, it happens twice per cycle with the waste-spark set-up and having two electrodes sharing the wear compensates for that.
I don't know about the 'more juice' part, though.
zcruiser
Senior Member
Oh, OK. Right, the spark will only jump to one of the two electrodes on any given cycle, and as soon as the metal is worn away on one it will start jumping to the other instead.
Blitzkrieg
New member
Correct on the first part.
However this thread got me thinking about this and I did some more digging. Interestingly enough electricity does not adhere to the rule water does (following the path of least resistance).
What IS guaranteed is that the current will pass to one of the two electrodes and ONLY one on any given spark pulse (or introduction of current). One electrode being more prominent (less worn) than the other does not guarantee it will be the one to ground the spark.
So, I have come to the decision that a dual electrode spark plug is a man, and the electrodes are two women standing on either side of him.
The man will send out a signal to the women without a clue as to how either one or which one even will respond. But the man doesn't care, as long as one of the women respond, he is happy.
Internal combustion paralleling life. ::artist:
zcruiser
Senior Member
I think we need mom to explain this to us. :guitar3:
kball
New member
SkidPalace
Member
The quote from XjeepGuy is right.
The Waste Spark or DIS (distributorless ignition system) fires each pair of plugs simultaneously, twice per cycle. The plug on the compression stroke fires normally and at the same time, the paired plug on the exhaust stroke fires as well. The spark on the exhaust stroke adds nothing to the power generation (hence the term "waste spark"), but it is rumored to burn excess combustion gasses adding to emissions improvements.
The system is also designed for economy as you only need one coil pack for every two cylinders.
NGK.com - Spark Plug 411
Essentially, to answer the dual ground question, yes, the spark plugs fire twice as often as regular plugs, cutting the life in half. Therefore, dual grounds would bring the life back to a normal mileage lifespan.
The Waste Spark or DIS (distributorless ignition system) fires each pair of plugs simultaneously, twice per cycle. The plug on the compression stroke fires normally and at the same time, the paired plug on the exhaust stroke fires as well. The spark on the exhaust stroke adds nothing to the power generation (hence the term "waste spark"), but it is rumored to burn excess combustion gasses adding to emissions improvements.
The system is also designed for economy as you only need one coil pack for every two cylinders.
NGK.com - Spark Plug 411
Essentially, to answer the dual ground question, yes, the spark plugs fire twice as often as regular plugs, cutting the life in half. Therefore, dual grounds would bring the life back to a normal mileage lifespan.
zcruiser
Senior Member
We need to bring this back around to Blitzkrieg's analogy somehow...
Blitzkrieg
New member
Good info on the 411 link.
Okay, so here's the analogy:
The incoming fuel is a gorgeous woman. The incoming air is her equally gorgeous friend.
The two electrodes see these two beauties coming into the Combustion Chamber Bar and Grill and try their best to spark up a conversation.
It goes well at first but very quickly after saying hi the two beauties get bored and leave the room to go to the restroom.
In walks the exhaust. She is Rosie O'Donnell. Desperate for female company and somewhat intoxicated the electrodes hit on the exhaust as she saunters in. Quickly they realize there is nothing exciting there, just hot air and fumes and she smells really bad too.
Wasted effort on their point but the night is young so they will try again and again.
:repuke:
Thats the best I got at this late hour. LOL
Nelsonmd
New member
Hmmm, I tried to get those plugs and wires from advance using the coupons, and it would let me order the wires. You must have gotten then last set they had.
And dang it, when I entered that part number it took me to the nickel electrodes, not the platinums. I guess I'll use the coupon again to get the platinums...
