Just put in a set of new plugs into my '92 FJ80 3fe. When I looked up the sp gap online, they said .40 When I picked up the plugs they had the Haynes manual on sale for $9.99, so I picked that up and they said the gap should be .34 so that's what I made them. Looking through the owner's manual today, it says the gap should be .43 so.....is it really that important to have to pull all the plugs, regap them, and reinstall them?
How important is spark plug gap? (1 Viewer)
- Thread starter Nonprophet
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How does it run?
- Thread starter
- #3
Well, that's a good question. It sat in a neighbor's yard for over 5 years. Never started, just sat there. So, the gas in it was terrible and when we first started it, it ran like crap. I drained the tank, put in fresh gas and some Lucas injector cleaner, and after a 100 miles or so of driving it's running MUCH better. I changed the plugs a few days ago, and that made a difference as well. It still idles a little rough when cold, but, the nipples on the EGR vlave broke off years ago so the EGR is not functioning at all....
When the plugs wear a little on my 94, it starts using oil. Runs fine and gas mileage stays the same, but just uses oil till I change the plugs. My 2 cents
The spark plug gap is directly proportional to the voltage rating of the coil. If the gap is too far apart, the coil may not be strong enough to make a good, strong spark to cause the gas mixture to burn as designed. The difference between .34 and .44 is roughly 25%. As the air gap gets wider, it requires more energy to cross that space. You are going to need a coil rated to deliver more voltage to cross that greater gap to run right.
Mmm ... said it two ways. Either way, it is an easy enough fix to make it right so you will know that that is not a problem later on.
Mmm ... said it two ways. Either way, it is an easy enough fix to make it right so you will know that that is not a problem later on.
Aggiesdm
***** Regular
confused also
So, what is the consensus for gap measurement? I had the same questions. I got three different numbers from 3 different sources and 2 of them were from Toyota. Not sure what the correct gap was, so I went with .4
So, what is the consensus for gap measurement? I had the same questions. I got three different numbers from 3 different sources and 2 of them were from Toyota. Not sure what the correct gap was, so I went with .4
Your missing a zero after the decimal point. Makes a huge difference. .34 is three hundred fourty thousandths of an inch. .44 is four hundred, forty thousandths of an inch. That's slightly less than 3/8" to just barely more than 7/16" of an inch. Not exactly the same gap as one needs. I am guessing you meant to put, .034 which is thirty four thousandths of an inch, to .044 which is fortyfour thousandths of an inch. Makes a huge difference.
Can't tell you if it makes that much difference between the ten thousandths of an inch from your low to high recommendation. Ten thousandths is about the thickness of two and a half shims made from a aluminum soda can.
Can't tell you if it makes that much difference between the ten thousandths of an inch from your low to high recommendation. Ten thousandths is about the thickness of two and a half shims made from a aluminum soda can.
The gap grows on my 80 to about twice the size I set the gap when its time to change them out. The motor runs fine and mileage is not affected.
How does oil consumption relate to the gap of the plug?
How does oil consumption relate to the gap of the plug?
The correct gap for your FJ80 3FE is 1.1mm or .043".
The recommended plugs:
ND W 16EXR–U11
NGK BPR5EY 11
If you notice the part numbers both have "11" in the suffix. That is 1.1mm gap from the factory.
The .034" spec you were given is for the 3FE in an FJ62 which has a different coil/igniter assembly.
In my truck, spark plug gap makes a difference.
The recommended plugs:
ND W 16EXR–U11
NGK BPR5EY 11
If you notice the part numbers both have "11" in the suffix. That is 1.1mm gap from the factory.
The .034" spec you were given is for the 3FE in an FJ62 which has a different coil/igniter assembly.
In my truck, spark plug gap makes a difference.
steffan
SILVER Star
I used a spark plug tester at the race shop I worked at. The gap wasn't that critical until you started running high heat/ compression along with the coil combination. With these motors being what they are, the tolerances are pretty wide without any noticeable affects. That being said, I still don't understand the relationship between spark plugs and oil consumption
I would spend the time to gap them all to 1.1 mm.
Aggiesdm
***** Regular
Your the man Mr. Held
Just buy the factory plugs and don't worry about gaping them.
