Awhile back, i switched to a set of Bosch plus-4 Spark Plugs cause i
heard a few times they give better fuel economy and performance. But
ever since i did, about every 20,000 miles I get at least one
ignition wire blowing out thru the sidewall of the boot on the spark
plug end. This time it has occured on the #6 boot/plug .
Do these Bosch plus-4's have a higher resistance ? Maybe im better
off going back to what the car came with ?
1) The boots are not all the way down on the spark plugs...
possibly lacking 1/2" to 1".
2) The spark plug wires and boots are made of very cheap material.
(Use silicone wires and silicone boots.)
Resistance should not matter, however, normal wires tend
to run about 5k per foot when new.
IMO, the four electrodes are a costly but worthless gimmick.
"Factory set gap" - Every car is different. They could not
possibly stock all those different gaps.
The spark will jump to the closest electrode = one is actually
On Mon, 09 Jan 2012 19:06:13 -0600, Paul in Houston TX wrote:
A bit off topic but some years back a Bosch spark plug
failed on my daughter's Toyota. The ceramic insulator
blew away from the metal threaded insertion nut, leaving
the nut embedded in the cylinder block, had to get an
'easy-out' to remove it. I sent it back to Bosch
and they sent a set of replacement spark plugs.
I changed out the Bosch plugs and went with the standard plugs. Also
put on a set of Bosch wires with lifetime warranty . The old plug
boot on number 6 blew a hole in the side of the boot , and, another
boot was about to do the same --- all this after just 20 k.
miles . I too think the Bosch plus 4's are gimmicky now.
The bigger question is the spark plug wires. With 114k, the originals
would likely be deteriorated. If you've installed aftermarket
replacements, that may also be an issue. I know there are some who
disagree with me here, but I've had great difficulty finding plug
wires which compare in quality to the originals.
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