thx....this is kind of what i was thinking as well.....
so the search continues to get at least 15 mpgs........
barrypt5
MAF & TB Plate Cleaning - PICS
- Thread starter uzj100
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
thx....this is kind of what i was thinking as well.....
so the search continues to get at least 15 mpgs........
barrypt5
Something strange happened to me in my 2000 Hundy about 6 months ago that also recently reared it's head on the new-to-me 2007.
In the 2000, MPG's fell WAY off with no other indicators of an issue. After a few days of driving, I found myself in a situation where I had to back and turn as I left a parking spot. I got a little drivetrain bind as I reversed and had the wheel turned. The obvious WTF hit my face and I knew it was the center diff locked, but there were no lights indicating it on the dash. Checked the button on the console and sure enough, the button was depressed, locking the differential in the transfer case.
Once I unlocked the diff, the MPG's went right back up. I could press the button and the lights would come on as usual. I don't know why they weren't on before, but they worked every time I tried it afterwards, so I wrote it off as being part of the ECU issue I was having and forgot about it.
Fast forward to yesterday... I'm driving down to a meeting in my 07 and I'm only getting 14.6 MPG @ 70 MPH. I normally get 17+ on the highway. Truck feels funny on the slow banking turns of the interstate and I actually have to give it a touch more throttle in the turns to maintain speed. No lights indicating any issues are showing on the dash. Well, after driving 200+ miles and parking, I come out with a client to take him to lunch and back out of my parking spot. I immidiately feel the driveline bind and I look at the dash - no lights. Look at the switch and it's depressed. I de-activate the center diff lock and no lights. Push again to activate and the lights come on.
Strange.
After un-locking the center diff, the truck immediately went back to "normal" handling and on-road feel and the MPG's on the way home was an average 17.6 when it was only 14.6 for the trip up.
Needless to say, CHECK THE CENTER DIFF LOCK SWITCH, even if the lights aren't on. Only thing I can attribute this to is that a few days before my 7-yr-old son was in the truck and pushed some of the NAV buttons. I guess he pushed the CDL button too (he can't remember now) when the truck was not running, but the key was in the ACC position. For some reason the status wasn't indicated with the light on the dash and the VSC OFF didn't illuminate either, even thought the button was depressed and the CDL was definitely locked.
Worth checking if you're running abnormally low MPGs for sure.
In the 2000, MPG's fell WAY off with no other indicators of an issue. After a few days of driving, I found myself in a situation where I had to back and turn as I left a parking spot. I got a little drivetrain bind as I reversed and had the wheel turned. The obvious WTF hit my face and I knew it was the center diff locked, but there were no lights indicating it on the dash. Checked the button on the console and sure enough, the button was depressed, locking the differential in the transfer case.
Once I unlocked the diff, the MPG's went right back up. I could press the button and the lights would come on as usual. I don't know why they weren't on before, but they worked every time I tried it afterwards, so I wrote it off as being part of the ECU issue I was having and forgot about it.
Fast forward to yesterday... I'm driving down to a meeting in my 07 and I'm only getting 14.6 MPG @ 70 MPH. I normally get 17+ on the highway. Truck feels funny on the slow banking turns of the interstate and I actually have to give it a touch more throttle in the turns to maintain speed. No lights indicating any issues are showing on the dash. Well, after driving 200+ miles and parking, I come out with a client to take him to lunch and back out of my parking spot. I immidiately feel the driveline bind and I look at the dash - no lights. Look at the switch and it's depressed. I de-activate the center diff lock and no lights. Push again to activate and the lights come on.
Strange.
After un-locking the center diff, the truck immediately went back to "normal" handling and on-road feel and the MPG's on the way home was an average 17.6 when it was only 14.6 for the trip up.
Needless to say, CHECK THE CENTER DIFF LOCK SWITCH, even if the lights aren't on. Only thing I can attribute this to is that a few days before my 7-yr-old son was in the truck and pushed some of the NAV buttons. I guess he pushed the CDL button too (he can't remember now) when the truck was not running, but the key was in the ACC position. For some reason the status wasn't indicated with the light on the dash and the VSC OFF didn't illuminate either, even thought the button was depressed and the CDL was definitely locked.
Worth checking if you're running abnormally low MPGs for sure.
Last edited:
Scary to think my two year old was playing in the driver seat....will definitely check that....thanks for the tip
barrypt5
mine is averaging 15.2 per tank with mixed Hwy and City driving.... fuel bill went from $400 to $750 / month buying this thing... hahaha but I love it... I am doing the cleaning tonight on the TB but my best solution is going to be buying a BMW 1150RT... haha
holy high miles batman! you're driving close to 3k miles per month! hopefully all/some of that is reimbursable!
$750/mo in gas?! 
I feel you on the desire for a bike (nice choice by the way, Littleton PD just switched to those for their motor cops...BMW is too spendy for me though). Even my motorcycle-hating wife is considering letting me pick up a KLR650 to tool around on.
It's been nice out, I think I might tackle the TB tomorrow and see if I can get this pig up above 16mpg before I slap the ARB on next week...
I feel you on the desire for a bike (nice choice by the way, Littleton PD just switched to those for their motor cops...BMW is too spendy for me though). Even my motorcycle-hating wife is considering letting me pick up a KLR650 to tool around on.
It's been nice out, I think I might tackle the TB tomorrow and see if I can get this pig up above 16mpg before I slap the ARB on next week...
JB, if you haven't already, check out bamachem's 07 thread about his mileage pickup with his fluid changes.... has me curious.
Easy way to double fuel mileage? Drive a different vehicle. Works like a charm!
I've actually been following that with some interest, Dennis. I'm planning on slowly transitioning to synthetics for everything as time and money allow, but the new bumper will throw my numbers off with the added weight. If I can keep it around 13 mpg mixed driving with the ARB and (eventually) sliders, I'll call that a success. Not holding my breath, but it would be nice.
It'd be nicer if the
finally broke down and let me buy a bike...mileage problem solved.
i get 15 in city. that is pissing everybody off behind me leaving the stop lights. I am SO slow getting to speed, but once I get my speed up I am quick
I drove about 240 miles non-stop today on the highway and avg'd about 18.1mpg. No traffic, no stop and go, 70-85mph. Keep your air filter clean, MAF and TB clean and you should be golden. The trick for me is to pick up speed going downhill, when I hit the flat stuff I drop back down 5mph and hold steady. Uphill, well you can't really do much about it. I am 1100ft above sea level, GA interstates are very flat and straight (for the most part where I go to school)
I drove about 240 miles non-stop today on the highway and avg'd about 18.1mpg. No traffic, no stop and go, 70-85mph. Keep your air filter clean, MAF and TB clean and you should be golden. The trick for me is to pick up speed going downhill, when I hit the flat stuff I drop back down 5mph and hold steady. Uphill, well you can't really do much about it. I am 1100ft above sea level, GA interstates are very flat and straight (for the most part where I go to school)
I get 13 mixed, half uphill half down.
Another trick is coasting. The 04 FSM shows that the LC completely cuts fuel off when coasting and RPM's are above 1150 (?).
The technique is easy but you have to deliberately do it. Most people will feather the throttle rather than completely come off it when coming up on traffic, a slight downhill, a light, etc. Rather, completely come off on the gas for as long as possible, even if that mean you'll need to accelerate slightly later. It may seem a counter-intuitive but you're instantaneous mileage goes to infinity while the fuel is off which outweighs the need for light acceleration later.
Since I have neither a scan gauge to show flow or an '00 manual I can't say for certain which year this begins. I think it was Nick (?) who was posting some flow numbers a while back? Perhaps he could confirm?
Regarding light vs heavy acceleration, I remember watching something on this a while back. Might have been Myth Busters. Anyway, the key is to quickly get up to cruise speed without down shifting. RPM's are bigger fuel killer than throttle position (look a diesels - WOT and low rpm all the time). So apparently it's better to be a little heavy with the foot as long as the RPM's stay down. Less pumping losses, less total time accelerating, more time at high-efficiency cruise.
The technique is easy but you have to deliberately do it. Most people will feather the throttle rather than completely come off it when coming up on traffic, a slight downhill, a light, etc. Rather, completely come off on the gas for as long as possible, even if that mean you'll need to accelerate slightly later. It may seem a counter-intuitive but you're instantaneous mileage goes to infinity while the fuel is off which outweighs the need for light acceleration later.
Since I have neither a scan gauge to show flow or an '00 manual I can't say for certain which year this begins. I think it was Nick (?) who was posting some flow numbers a while back? Perhaps he could confirm?
Regarding light vs heavy acceleration, I remember watching something on this a while back. Might have been Myth Busters. Anyway, the key is to quickly get up to cruise speed without down shifting. RPM's are bigger fuel killer than throttle position (look a diesels - WOT and low rpm all the time). So apparently it's better to be a little heavy with the foot as long as the RPM's stay down. Less pumping losses, less total time accelerating, more time at high-efficiency cruise.
Yep, oregonlc is right. I confirmed this a few minutes ago. The 100 just cut 100% fuel delivery upon coasting above 1150RPM. Scangauge reads 0.00gph on downshifting wether from 65mph or forcing it into "L" in parking lots. As long as it's above the RPM limit.
Upon full throttle I can see upwards of 15.9GPH. Max RPM on drive was 4260. Drove 2.7miles, water temp was 193*F, used .34 gallons and avg mpg was 8.2.
I do feather the throttle on downhill when I get the chance or remember. I haven't payed much attn to GPH but will watch it. I have a video I will post later showing fuel cut at different speeds and several different driving conditions and the SGII reading my input.
Upon full throttle I can see upwards of 15.9GPH. Max RPM on drive was 4260. Drove 2.7miles, water temp was 193*F, used .34 gallons and avg mpg was 8.2.
I do feather the throttle on downhill when I get the chance or remember. I haven't payed much attn to GPH but will watch it. I have a video I will post later showing fuel cut at different speeds and several different driving conditions and the SGII reading my input.
Last edited:
Thanks for confirming that Nick!
So here's another debate: are we better down shifting to keep the r's above 1150 but add wear to the drivetrain or are we better spending the fuel and sparing the mechanical bits? I'm voting for the latter.
I wonder if the 5 spd in the 03+ takes advantage of this by down shifting more autonomously? In the 02 ML320 I had for a while it would down shift in cruise to help maintain speed on a descent. It would do the same when you go on the brakes say on an offramp. Similar behavior with an 08 MDX that I owned only it was much more aggressive in holding rpm's up. The MDX felt much less 'slippery' when coasting than any other vehicle I've driven because of this, almost felt like a bad case of caliper drag. But... it also got gps confirmed mpg of as high as 26 mpg on the highway. Not too shabby for a 300 hp 8 passenger vehicle. Too bad I hated driving it!
So here's another debate: are we better down shifting to keep the r's above 1150 but add wear to the drivetrain or are we better spending the fuel and sparing the mechanical bits? I'm voting for the latter.
I wonder if the 5 spd in the 03+ takes advantage of this by down shifting more autonomously? In the 02 ML320 I had for a while it would down shift in cruise to help maintain speed on a descent. It would do the same when you go on the brakes say on an offramp. Similar behavior with an 08 MDX that I owned only it was much more aggressive in holding rpm's up. The MDX felt much less 'slippery' when coasting than any other vehicle I've driven because of this, almost felt like a bad case of caliper drag. But... it also got gps confirmed mpg of as high as 26 mpg on the highway. Not too shabby for a 300 hp 8 passenger vehicle. Too bad I hated driving it!
Different MAF?
Finally go around to cleaning my MAF and TB today...
TB was pristine...i cleaned it anyway, but doubt i did any good as there was very little residue on the rag when done.
MAF was also pretty clean, BUT, it was way different than all of the pics shown on this forum. My truck is an '06...did they change the sensors in the later years of the 100 series?
In any event, i sprayed it down as per the instructions.
Pics below.
Finally go around to cleaning my MAF and TB today...
TB was pristine...i cleaned it anyway, but doubt i did any good as there was very little residue on the rag when done.
MAF was also pretty clean, BUT, it was way different than all of the pics shown on this forum. My truck is an '06...did they change the sensors in the later years of the 100 series?
In any event, i sprayed it down as per the instructions.
Pics below.
Yes the 5spd downshifts on downhills in cruise and when you hit the brakes
ntsaint, it looks like I have the same MAF as you. I simply ripped the "permanent" post-filter element from my airbox to access the MAF instead of removing it. The element is not needed - it's not on the older trucks - and only causes more restriction on incoming air.
Anyway, when you do that, you can see the wire inside the MAF by looking up the tube towards the TB from the filter box. Spray that little wire w/o touching it. It should be the opposite side of your third pic you attached of your MAF.
On the TB, did you open the butterfly valve in the TB? The "filter" side of my TB looked that that too @ 54k miles. However, if you use a piece of plastic to open the BF valve, you will see some nasty black crud inside the body. I sprayed the hell out of it w/ aerosol seafoam, let it soak in, then wiped it out as best I could w/ a rag. It was NASTY.
Anyway, when you do that, you can see the wire inside the MAF by looking up the tube towards the TB from the filter box. Spray that little wire w/o touching it. It should be the opposite side of your third pic you attached of your MAF.
On the TB, did you open the butterfly valve in the TB? The "filter" side of my TB looked that that too @ 54k miles. However, if you use a piece of plastic to open the BF valve, you will see some nasty black crud inside the body. I sprayed the hell out of it w/ aerosol seafoam, let it soak in, then wiped it out as best I could w/ a rag. It was NASTY.