For your injectors, put in 2 cans of 44K. Drive it like you stole it, let it sit over night, and drive it like you stole it again. I typically do it with about 1/4 tank. It does magic stuff.
Another poor mpg thread. (1 Viewer)
- Thread starter LS1FJ40
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bloc
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Fwiw my 94 replacements in the Toyota kit were NGK. Forum wisdom definitely recommends using the Toyota parts in this case. If $200 is a sensitive amount I would get the injectors serviced first though, because it likely will make some difference, and is a good PM. By contrast the o2 sensors will either make a huge difference or virtually none, and will be a tough slog to do.
Lots of good info in here for 93/94s. I'm not quite at that knowledge level of engine performance, but some thoughts:
New plugs, wires, cap/rotor gave me 1/2 mpg increase
New O2 sensors gave me 1 mpg increase
Check/advance timing?
Excessive brake drag?
Gas leak due to plugged Charcoal can?
Check/adjust kickdown cable if you're feeling sluggish
Don't forget to add 6% to mileage when calculating mpg (285s)
I've never gotten bad mileage on my 93. I average 13-14 on trips and longer drives, loaded, with a bunch of crap on the roof, 285s at 42psi. Pretty light on the gas pedal, try to keep it around 65.
New plugs, wires, cap/rotor gave me 1/2 mpg increase
New O2 sensors gave me 1 mpg increase
Check/advance timing?
Excessive brake drag?
Gas leak due to plugged Charcoal can?
Check/adjust kickdown cable if you're feeling sluggish
Don't forget to add 6% to mileage when calculating mpg (285s)
I've never gotten bad mileage on my 93. I average 13-14 on trips and longer drives, loaded, with a bunch of crap on the roof, 285s at 42psi. Pretty light on the gas pedal, try to keep it around 65.
I've been getting mostly 12.8 to 13.8mpg on my 94 (stock with BFG AT KO2 285/75/16 and 286k miles). This is a mix of city, highway and off road for the last 1.5 years. I run regular 87 octane fuel (usually chevron or shell) and have the base timing set about as high as it will go before any pinging (8-9deg). Most of the time I'm between 3500-5500' elevation, EGR is disabled with the resistor. I leave the "PWR" button on all of the time (literally have never turned it off since I bought the beast).
The best MPG I've seen was 14.7, that was with stock tires and temperatures in the mid 90's, AC off, windows down and 55-75mph on the highway. The worst I've seen is mid 10's from offroading in low range mixed with dirt road driving at low speed.
Things that helped MPG:
- Repairing the injector wiring harness damage by the EGR that was causing misfires
- New spark plugs, wires, air filter, etc... tuneup
- Running a few cans of injector cleaner through the system
- No roof rack, lift or additional weight (assumption)
And those that reduced MPG:
- Larger than stock tires
What I'd like to try next:
- Removing the injectors for cleaning
- Remove the throttle body for a deep cleaning
The best MPG I've seen was 14.7, that was with stock tires and temperatures in the mid 90's, AC off, windows down and 55-75mph on the highway. The worst I've seen is mid 10's from offroading in low range mixed with dirt road driving at low speed.
Things that helped MPG:
- Repairing the injector wiring harness damage by the EGR that was causing misfires
- New spark plugs, wires, air filter, etc... tuneup
- Running a few cans of injector cleaner through the system
- No roof rack, lift or additional weight (assumption)
And those that reduced MPG:
- Larger than stock tires
What I'd like to try next:
- Removing the injectors for cleaning
- Remove the throttle body for a deep cleaning
I'm still getting the feel for my mileage and recently did some testing for MPG and ride at different tire pressures. I'm running 285/75R16 load range D mud tires(generic that were on the vehicle when I bought it). The best ride was at 32psi, however bumping up from 35psi to 40psi made a 1-2mpg average increase in mileage. I also noticed the vehicle maintained speed better with the higher tire pressure. The tires have 44K miles on them with 1/3 tread left but will be replace soon.I've done a pretty extensive overhaul of maintenance items on my '93 (including cleaning the injectors, air filter, plugs, etc) and am UP to ~12mpg mixed driving (started at ~11mpg before all the maintenance work). And I have a LIGHT foot on the pedal. No extra weight, no towing, no crazy burn-outs.
I figure mileage is the trade-off for not having to deal with OBDII
296k & 33" BFG KM2's @ 35 psi.
Hell I'm happy to get 10mpg anymore. All those claiming 13.5-15 with stock gearing and oversized tires need to get a speedo recalibration because your MPG's are off your calculating off an incorrect odometer reading, I thought I was getting better fuel economy than I was too until I installed the yellowbox and realized I wasn't driving anywhere near the distance I thought I was. @LS1FJ40 the EGR code is likely causing it a little worse consumption but O2 sensors on older cars of the 90's were scheduled for change most of the time around every 75k miles even newer cars it's recommended before 105k miles and if the O2 sensors aren't working you're losing fuel economy. I would ensure your Plugs are replaced, your O2 sensors are replaced and your cats aren't plugged and see how it fairs from there. An ECU reset (not code erase) would be wise after your O2 and plugs. Then drive around as you normally would for a few days. Then on the next tank compare fuel economy.
my 14.5 was with the stock tire size and stock gearing, and the orem-to-stgeorge run is an overall loss of a lot of elevation. my gps tells me that my speedo is more or less dead on.
and i was taking it easy.
I drive a little too aggressively and it burns a lot of gas.
Do newer cars have a recommended lifespan for an o2 sensor? my 07 VW just throws a code when the sensor is operating in an implausible manner or the internal resistance is too high. Modern ECUs are just that smart. fwiw the rear o2 sensor on that car started throwing codes at about 80k.
ON a recent 190 mile trip of mixed highway and offroading I averaged 14.01mpg based on fill up and odometer mileage which was under what I actually drove due to the stock gears and 285/75R16 tires. Stock gears plus larger tires means per revolution you are traveling further. My actual speed is ~2.5mph higher then what is read. FYI, most stock vehicles sold are designed to read higher than actual speed and distance. Motorcycles are much worse.
I have always used OEM O2 sensors for both the 91 and 97. At one point I was looking into aftermarket, but I never like to go down that road as it tends to leave a bad taste in my mouth.
I have used www.discountconverter.com for replacement downpipes/cats on the 91 with very good results and they carry direct fit O2 sensors as well, but I have never used them.
When I did the custom exhaust on the Lexus I used the Magnaflow downpipe/cat and new OEM O2s.
A seized fan clutch will cause additional drag on the motor and not allow the engine to reach NOT which can decrease mileage and overall performance.
Was the fuel pump pre-filter and inline filter changed or still original? This is on my list and sitting in my parts box.
Was the fuel pump pre-filter and inline filter changed or still original? This is on my list and sitting in my parts box.
Something is not calibrated right. No way you are averaging 18.5 mpg on a consistent basis.
97 cruiser on 255x85's with roof rack,sliders dual batteries, drawer system and rear tire carrier,also has a yellow box speedo correction...
55-60 mph, got me this...300k miles on motor...
Tire pressure of 50psi
4:10 gears
LS1FJ40
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- Thread starter
- #35
That's where I got my 02 sensors for my 92. I have zero complaints. I think I'm going to order them for the 93.
I have not replaced the pre-filter or inline filter yet. I guarantee they are original. I've heard the inline filter is a PITA! But don't know.
The fan clutch seems to be spinning as it should. No drag and not free wheeling.
Those are 100-150K mile maintenance items IMO. I looked at the inline filter the other day. Didn't look too horrible.
Maybe, just maybe, if you gassed up at the top of a steep hill reset your Ultragauge and hyper mile'd it down in Neutral
bloc
SILVER Star
Many of us have our speedo calibrated various ways.. Or at the very least knew that bigger tires would impact odometer accuracy so either did the math or used mile markers to derive an adjustment factor. Mine is done via GPS and SGI-5, and "dead on" is between two settings, so I went with the one that reports mileage a little short. With our stock speedos indicating a little fast, mine now reports closer to actual speed.
Trust me, I couldn't believe I hit high 15s with AC at 70 on one tank.. but the next one was all-freeway, GPS running the entire time to verify distance, and even topped up to the cap to avoid spout-stop error. 15.4. Outside of the actual off-roading, my worst tank that whole trip was 14.2. Headwind. I even have a second trip a few months apart to the same area with very similar results.
I attribute it to the high tire pressure, part-time kit (more on this in a bit), all new plugs/wires/filter, it being a 94 (seem to run leaner), maybe even the 0w-40 oil (100c viscosity is closer to a 30wt)... actually maybe not. Second trip was with 5w-40 diesel oil.
On the part-time.. same truck, same plugs/wires/fuel/etc, same run, same lift, same tires (though less pressure.. closer to 32), stock bumpers, no second battery, no winch, no sliders (so truck significantly lighter).. 12.5 on the identical freeway trip when full-time AWD.
So apparently a bit more pressure and part-time kit added 2mpg freeway, despite the few hundred # of steel/battery/winch and new front bumper being significantly worse from an aerodynamics standpoint. Though on that, I'm only running a low 2" lift, which probably helps.
Basically, my experience is that part-time DEFINITELY makes a difference, despite what (many) people on this board have posted. Which just makes sense, to me.
All of that said.. I think @LS1FJ40 needs to check condition of the catalysts. Would a bore-scope fit into an O2 sensor hole and turn backward to have a look?
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