HELP, I switched to NGK CR8EIX and my gas mileage drop!!

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CHRIS_D

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Help, I recently switched to the NGK CR8EIX Iridium (sp) plugs on my 2007 with 8500 miles and my mileage went from an average of 40 MPG to under 33 MPG. Yes, I have run a few tanks of gas, so I don't believe it's the gas. Anybody know why this may of caused such a big drop in mileage?

I did go back in and double check each plug to make sure the color and gap was correct. I also check to make sure that I didn't some how disconnect a vacuum line. I couldn't find anything wrong. Also when I originally replaced the plugs I also sync the throttle bodies, which I have done before without any problems. However this time, I didn't replace the wire clips that hold the rubber caps on because it's such a PIA.

If it's not plugs is it possible to get bad gas mileage if there is a small hole or leak in one of the throttle body rubber caps (where you connect the sync tool)? Has anyone come across this problem before?

Thanks in advance!!

 
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I haven't been watching the weather in the Atlanta area, but my mileage goes down when it's cold. Also,my right wrist always seems a little stronger in the cool weather. :)

 
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I haven't been watching the weather in the Atlanta area, but my mileage goes down when it's cold. Also,my right wrist always seems a little stronger in the cool weather. :)
Actually it's been pretty warm here. :) I was still getting around 40 MPG when it was much colder. I hate to do it but maybe I should just throw in the old plugs and see what happens.

 
If it's not plugs is it possible to get bad gas mileage if there is a small hole or leak in one of the throttle body rubber caps (where you connect the sync tool)?
Absolutely yes. That would constitute a vacuum leak and your mileage would go down. I've not had one develop a hole, but I have had one blow clean off (on a BMW boxer, not an FJR)

 
If it's not plugs is it possible to get bad gas mileage if there is a small hole or leak in one of the throttle body rubber caps (where you connect the sync tool)?
Absolutely yes. That would constitute a vacuum leak and your mileage would go down. I've not had one develop a hole, but I have had one blow clean off (on a BMW boxer, not an FJR)
I think since you didn't put the clip back on the rubber caps one of them has come off - a small vaccuum leak like that would affect gas mileage.

 
If it's not plugs is it possible to get bad gas mileage if there is a small hole or leak in one of the throttle body rubber caps (where you connect the sync tool)?
Absolutely yes. That would constitute a vacuum leak and your mileage would go down. I've not had one develop a hole, but I have had one blow clean off (on a BMW boxer, not an FJR)

Thanks Fred,

It makes sense!! It looks like I will be replacing those rubber caps. I have to admit I might of puncture one when I was taking them off with the needlenose pliers :dribble: I know this is not the best tool to use!!

 
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I have to admit I might of puncture one when I was taking them off with the needlenose pliers :dribble: I know this is not the best tool to use!!
No, it is not.

I suspect you have inadvertently introduced the problem when you installed the plugs. The CR8EIX spark plug is outstanding, and has been used by countless FJRs over the years with flawless results, so I'm pretty sure it ain't them.

Good luck hunting this down... I would like to think it's something as simple as you tearing a rubber cap (or otherwise introducing a vacuum leak), but if that was the case, you should also be seeing poor idling and/or other engine tuning misbehavior. :huh:

 
I have to admit I might of puncture one when I was taking them off with the needlenose pliers :dribble: I know this is not the best tool to use!!
No, it is not.

I suspect you have inadvertently introduced the problem when you installed the plugs. The CR8EIX spark plug is outstanding, and has been used by countless FJRs over the years with flawless results, so I'm pretty sure it ain't them.

Good luck hunting this down... I would like to think it's something as simple as you tearing a rubber cap (or otherwise introducing a vacuum leak), but if that was the case, you should also be seeing poor idling and/or other engine tuning misbehavior. :huh:

It was really stupid using the wrong tool!!! Those little caps are $2.50 a piece! WOW! :dribble:

 
I have found the best tool, for me, for removing the wire clamps on the vacuum nipples is a pair of curved hemostats. lock on and no worry with shootin the clamp across the garage..

I just got 55 mpg on my '05 FJR with a worn set of those plugs.
FJRMGM, How in the world are you getting 55 MPG? :unsure: Do you ride at 40 MPH? :rolleyes: J/K!

Please share your set up for your awsome mileage.

The only time i got anywhere close to 50 MPG was when i rode with several Harley bikers on a sunday ride.

They didn't ride any faster than 50 MPH the whole 6 hours we were out. real world riding on my '05 i get 39-44 MPG.

later

cadman

 
If you put a tiny dab of silicon grease on the nipples the caps will go on and off more easily. Don't get any in the hole where it can be sucked into the engine.

 
If you put a tiny dab of silicon grease on the nipples the caps will go on and off more easily. Don't get any in the hole where it can be sucked into the engine.
Be aware that silicone is highly detrimental to oxygen sensors ($$).

I use silicone grease on the intake boots on carburetted bikes, but they ain't got no O2 sensors.

 
<snip>The only time i got anywhere close to 50 MPG was when i rode with several Harley bikers on a sunday ride. They didn't ride any faster than 50 MPH the whole 6 hours we were out.
Don't be doin' that.

I left a national rally once on the FJR and there was a small group of H-Ds looking like they were going my way -- and I thought, "I'll follow them for a while...". We eventually parted and when I stopped for lunch I looked at my bike -- "What's all this sh%t all over the front of my bike?"

Oil. :( :angry:

BTW, I get close-to 50mpg once-in-a-while -- it's 'steady' throttle (imo) that does it.

 
I have found the best tool, for me, for removing the wire clamps on the vacuum nipples is a pair of curved hemostats.
I bet I have done a couple hundred TBS exercises on the FJR during the past 6 years, between the 2 that I've owned, a half-dozen TechWest seminars, in the parking lots at Moscow, ID, Reno NV and Park City, Utah, etc.

I have found the best method for dealing with the wire clamps on the vacuum nipples is to pull those bastards off and throw them away as far as possible. :lol:

They are 100% completely unnecessary. Seriously. They do fuck all as far as a meaningful retaining device.

Avoid the hassle. Fling them. The nipples are just as difficult to remove without them... the tight press-fit is more than enough to retain them in place and keep the orifice leak-free.

 
I have found the best tool, for me, for removing the wire clamps on the vacuum nipples is a pair of curved hemostats.
I bet I have done a couple hundred TBS exercises on the FJR during the past 6 years, between the 2 that I've owned, a half-dozen TechWest seminars, in the parking lots at Moscow, ID, Reno NV and Park City, Utah, etc.

I have found the best method for dealing with the wire clamps on the vacuum nipples is to pull those bastards off and throw them away as far as possible. :lol:

They are 100% completely unnecessary. Seriously. They do fuck all as far as a meaningful retaining device.

Avoid the hassle. Fling them. The nipples are just as difficult to remove without them... the tight press-fit is more than enough to retain them in place and keep the orifice leak-free.
+1

I was gonna say the same thing but figured I'd get flame roasted for it.

I see no reason to clamp a vacuum line unless you are riding a bike that backfires thru the intake regularly.

 
Never had a problem with just using my fingers to pop them off and back on (this with the stainless retainer clips still afixed). I too use just a smidge of silicone grease to ease exit and entry of the caps. By a smidge I mean just enough to coat the rubber (not enough to foul the O2 sensor).

 
<snip>The only time i got anywhere close to 50 MPG was when i rode with several Harley bikers on a sunday ride. They didn't ride any faster than 50 MPH the whole 6 hours we were out.
Don't be doin' that.

I left a national rally once on the FJR and there was a small group of H-Ds looking like they were going my way -- and I thought, "I'll follow them for a while...". We eventually parted and when I stopped for lunch I looked at my bike -- "What's all this sh%t all over the front of my bike?"

Oil. :( :angry:

BTW, I get close-to 50mpg once-in-a-while -- it's 'steady' throttle (imo) that does it.
The ride was with a few of my friends and yet a few more of their friends...All of the bikes are relativly new. After returning home, i didn't have an oil film bug screen. :D

shoot, steady throttle on a FJR...yea, ..right! :rolleyes:

WC, the clips are indeed a PITA...Next TBS i'll think about shortening up my time by leaving them off...thanks.

cadman

 
I put silicone hose extenders from the vacuum fittings.

Labeled with the cylinder numbers and glued to two small flat pieces of plastic.

Double barb fittings in the hose end with longer black rubber caps.

More better, easier to get to, and you don't have to fish the caps out of the

deep hole and drop them in the black hole.

 
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