MPG woes

[Seanz0rz]

put the shims up on ebay or in the classifieds here. I know there are alot of people who like to collect parts.

as for disc brakes, it just isn't worth the cost on our rigs. I really looked into it, but the slight increase in performance and lessening of the PITA factor isn't worth the few grand it costs.

[Kryptoroxx]

put the shims up on ebay or in the classifieds here. I know there are alot of people who like to collect parts.

as for disc brakes, it just isn't worth the cost on our rigs. I really looked into it, but the slight increase in performance and lessening of the PITA factor isn't worth the few grand it costs.

Hmmm I didn't think it would cost that much. I was going to go to the junkyard for most of my stuff.

stamped and snail mailed

[Kryptoroxx]

Just a quick update and this will apply to the 3.4 or the 2.7 as well. I needed to do my oil change and tire rotation anyway today but before I went I put half a can of Seafoam and had the engine running and driving for about an hour before I went in and changed it. Man did it make a difference. I also have been running Lucas synthetic oil stabolizer (about a pint each change) while I run a 10w/30 Mobil One Synthetic. Next paycheck will be new belts and flush on the radiator and the brakes if finances will allow for me to do that. So here's what's been done so far.

Gear oil change
Tranny and xfer oil change
Valve adjustment
Complete Seafoam treatment (vacuum, crankcase, and fuel tank)

Results have been a much smoother idle and "lighter" feel in the skinny pedal. I know my mpg has gone up but I am waiting to see by how much. I will calculate next tank.

[Kryptoroxx]

*Update*
Discovered 2 things wrong with my initial tranny oil change. It's the wrong type. I should have done more research but everyone swears by the Redline MT-90 GL4 for the w59 so that's what is sitting in my garage right now.

Also might be looking at changing out an o2 sensor or MAF. I am still trying to work out if mine are reading properly. I am doing more research but at least I have my scan tool helping me out. Unfortunately I am not an expert on reading the data displayed so BattleWagon was giving me a hand for a little bit tonight trying to see what's up. I'm running below 20mpg all of a sudden and I'm chasing down the why.




This is going to take more research but I want to get this sorted out before Colorado. I am still fighting to get the time to do the regearing (which may or may not help) from 4.1 to 4.3. I think since I run a slightly oversize tire it will help however if I have a failing coil, a/c compressor, bad o2 sensor, bad maf, or anything else it will definitely hurt fuel econ. It could also be a failing fuel pump. All of a sudden my truck will die at idle sometimes....it just started a couple of days ago. Not too worried about it on base but if I'm on my way to colorado where I can't do it myself that pump could hurt the pocketbook a lot.

[Seanz0rz]

What the regear will do: Going numerically higher with the bigger tires will take you closer to a stock final drive. The reason I haven't regeared (other than the cost) is the highway mileage. Since I am turning about 2000 rpm at 70 (or close to), I get good highway mileage. I get trash mileage in town and climbing hills since the engine struggles at acceleration and there is not enough torque at low RPMs to push me up a hill. I require a down shift to make it up at speed, or I'm required to go very slow, but still in a lower gear.

what all that means: With bigger than stock tires, numerically low ratios will net you a lower cruising RPM and possibly an increase in MPG on the highway. Numerically higher ratios will give you more torque at slower speeds, and possibly better MPG at slower speeds at the expense of cruising MPG. Obviously dozens of other factors, but that is what I have found to be true over the last nearly 8 years of owning a lifted truck.

I can't pretend to understand anything about O2 sensors. They are witch craft as far as I'm concerned. I replaced mine a while back when fuel economy hit the bottom. They helped a bit, but there are probably other issues.

I too have the truck nearly stall at idle, especially after coming off the freeway. I suspect the idle air control valve is failing, but it could also be a leaky/stuck fuel injector. I don't think it is the fuel pump since I have no problems close to redline, even for slightly extended jaunts.

[Kryptoroxx]

I think I might just get some fuel system cleaner and see if that doesn't help. I've been watching youtube videos of all the problems I might have and it makes me wonder if they do maintenance at all. It seems to be a fuel issue but I chased down prices on all the parts that it could be with no real answer yet

Fuel pump $368
Fuel Injector set (these are balanced from LC) $200 with a $48 core charge
Ignition Coil Set (paradise racing has a whole bunch of these used for $60 a pair (worth it to me as lots of guys go buy cherry 2/3rz engines and then send them off to paradise for forced induction...and they are OEM)
A/C Compressor I think I found some Denso's for 250 or so but I am going to wait till the summer prices drop. My compressor isn't that loud yet.

I'm going to check my plugs and wires tonight if I get some time. I also have to get my rollbar ready today. I am painting some rocker panels this weekend and I know there will be lots left over for me to paint it....but I have to be able to paint it so I have to fabricate it today...or at the latest tomorrow so I can paint and cure the paint the rest of the weekend.

[4x4mike]

It seems you have a lot going on. You're mentioning a couple concerns (problems?) as well as replacing items.

I'm going to start with the diagnostic screen shots. You posted them up because you seem to be under 20 mpg, correct? Is this 20 mpg number from your calcs or the program? What were you using before the program? Just so you know most of the regular posters here get below that and have perfectly functioning vehicles.

Also, were the screen shots taken just after start up? After being driven and warm? You've got two screen shots with differing RPM while some of the numbers remain the same.

I've got an Ultra Gauge and I have it set up a little different but below are some of my numbers. These pictures were taken in the Spring, at start up in the morning.








I'm not sure what I was really after when I took the pictures other than a baseline for a typical start up. A few days a week I have a 2 mile drive to a park and ride. The drive is short enough that in the colder weather I don't enter closed loop before shutting it off. As a result my gas mileage takes a dive.

The first picture doesn't show much other than what my running MPG is. It's on the low side due to those short cold trips. Currently in the summer it's better. Second pic is showing my warm up high idle and that the temperature is in the mid 50's. Third shows a typical warming up timing. I had no idea what it was before the UG but it's good to know what my baseline is. My MAF is on grams/sec but you get the idea. The bottom 4 fields are the short and long trim along with the voltage to the O2 sensors. These numbers are typical for warm up.

I'll look to see if I have some driving screen shots to compare. Hopefully these will be something you can compare to.

[Kryptoroxx]

I am starting to think that mine might be from a similar situation. My commute consists of a 3 mile distance with speeds usually below 35mph. I do this twice a day and that's my usual driving. On the off hand chance I will drive to yucca valley or down the hill giving my engine a chance to run at 70 for at least 30 minutes.

[4x4mike]

Here are a few while driving. The RPMs seem a little high but it's a data point for the tire size/RPM talk above. These were at 61.5 mph and 2450 RPM. I think cruising at 68 I'm around 2400.





I'm not sure how long I had been driving here but freeway timing is at least 30*, for the most part short term fuel trim is at or near zero and if you look at it just right the sensor voltages add up to around 1.

I'm not sure how your phone program works but the UG took awhile to learn the 4Runner. This is one of the reasons I haven't put it in my wife's car. The OBD ports are the same but the protocol is different so the fields have to be tailored for the particular vehicle. After a few tanks of fuel I got the range and gallons dialed in. One thing that is still off is the horsepower and probably the torque. I haven't cared much to tinker with it but maybe someday.

[CJM]

Im with Sean on this:
-When I went to larger tires abnd wheels (265/75/16 and 16 wheels ") it dropped my overall cruising rpm around 70mph to about 2700 vs the 3000rpm I was getting with 31" tires (31x10.5x15 and 15" wheels). But I suffer around town slightly, truck is sluggish. However I have 4.30 gears and different gearing in my trans vs you guys so it might be similar or not.

My mpg over the winter was HORRIBLE, were talking about 11-12mpg overall. There was alot of idling, the heater core was slightly clogged and the flapper valve was no good as well and cracked. I also was commuting using 4wd. HOWEVER once winter was mostly over and I had fixed all of that I still was getting piss poor mpg. Bought a new upstream sensor cause the old one got melted and now that it was summer when I did it I was getting between 14.5-16mpg.

All my driving is local roads about 50-60mph with some stop and go and then a stretch of about 5 miles of highway at 50-60mph with some lights.