I finally got out wheeling again in mid-February. Joined up with a group in Death Valley
(California), for 3 days of desert fun.
First day saw a couple of sliced tires and one 4Runner with a leaky
radiator hose. On the second day, I had
to fire up the Premier Power Welder and reinforce a steering box that was
pulling loose from the frame on another 4Runner. All in all it was a fun trip.
Hi Roger;
Got any suggestions on a throttle body (TB) upgrade for a
95 Toyota 4x4 22RE engine? Getting ready to add a LCEngineering header and
would like to perk up the TB too. Also
could you tell me how much anti-freeze the radiator holds? I don’t have the owner’s manual.
Randy Hembree
Hi Randy;
Several companies offer bored out TBs:
LC Engineering is one: http://www.lcengineering.com/EFIsystems.htm
DOA Racing Engines is another: http://www.doaracingengines.com/4cylinduction.html
A 3mm over-bored TB will help the engine breathe better,
especially when combined with a mild cam and exhaust headers. You already have the improved TB and intake
on your ‘95, so you would probably see less improvement than I did on my
earlier ‘85 engine.
Radiator should hold about 8.9 quarts of coolant:
http://www.4crawler.com/4x4/4R_TechInfo.shtml#Fluids
[A reply from Randy]
Hi Roger;
Thanks Roger for the quick response! I have another
question for you, how much oil does the manual transmission and rear
differential hold? Also, you think with
the LCE header, Hotshot cold air intake, and 2 ¼ cat-back with Flow-Master muffler, the cam
would be better than the bigger TB?
Which cam would you recommend?
Rando
Hi Randy;
The web page that I sent earlier lists all the fluid types
and quantities, including the 3.2 qt. volume of the 22RE 5-speed transmission
and 2.3 quarts for the rear differential:
http://www.4crawler.com/4x4/4R_TechInfo.shtml#Fluids
Never tried the combination of engine upgrade parts you
list, so can’t comment on them specifically.
Making the engine breathe better is the whole idea. You need to get air to the engine (intake),
then you need to get the air into the engine (cam and valve train) then you
need to get the exhaust gas out of the engine (header and exhaust). Improve 2 of the 3 and you only get part of
the benefit. I documented my 22RE engine
buildup on my web page:
http://www.4crawler.com/4x4/CheapTricks/EngineMods/index.shtml
I installed a larger TB, TRD Level 1 cam, LC Street
Performer header and a 2” stainless steel exhaust. 2-1/4” is supposed to be a good size for a
22RE engine, I went with 2” to preserve the low end torque and I also had all
the material to fabricate it left over from other projects, outside the
muffler.
Hi Roger;
I have a 1985 4WD pickup, 22RE engine and a camper
shell. Every time I fill the tank, I
check the mileage. I always got 25-27 MPG on the highway and never less than 22
MPG. Then, at 54,000, I filled the gas tank once again. To my horror, the gas
mileage had dropped to 15 MPG! Since then,
I get 19-21 MPG with a few 22 MPG tanks.
I shorted the test plug under the hood and read the Check Engine Light
(CEL) in the dash. According to that, nothing was wrong. The tires have always been the same size as
stock.
At 110,000 miles, I had to replace the head gasket. The
coolant in the overflow reservoir was disappearing quickly and there were
exhaust gasses in the radiator. I got a valve job, had the head shaved,
replaced the exhaust valves, new timing chain and gears, and new plastic chain guide.
The oxygen sensor was replaced with a Bosch unit. Gas mileage remained the same but once the
CEL came on indicating the Air Intake Valve was faulty. I performed the field test on the valve and
it checked out OK. I’ve since checked
every electrical connection for corrosion. The only questionable connection was
the plug on the Mass Airflow Sensor. I cleaned the tabs and put it back
together. Still no change in gas mileage.
Someone suggested checking out the Throttle Positioning
Sensor (TPS). I do believe that a smog technician adjusted it one day (I can’t
tell you if it was before or after the initial drop in MPG). I adjusted it
according to the Toyota manual (the adjustment screw was turned in a couple of
turns too far) and tested the resistance at different points as noted in the
shop manual. No change in MPG. It seems there is some room for
interpretation as to the correct gap between the adjusting screw and the sensor
plate.
Clearance between Between
terms Resistance My Results
lever and stop screw
0.00 mm (0.000 in.) VTA
- E2 0.2 -0.8 k ohms 0.482 k ohms
0.57 mm (0.0224 in.) IDL
- E2 < 2300 ohms Infinity
0.85 mm (0.0335 in.) IDL
- E2 Infinity Infinity
Throttle fully VTA
- E2 3.3 - 10 k ohms 4.61 k ohms
open position Vcc
- E2 3 - 7 k ohms 4.58 k ohms
I tried turning the screw ½ a turn out and driving it
around for a few tanks. No change in MPG. I repeated this test again turning
the screw out another ½ turn, still no change in MPG. Then I turned it in 1-1/2
turns, still no change in MPG.
Last week, with 128,000 miles on the truck, I was driving
the truck in first gear 2wd, on asphalt, for ½ mile and the CEL came on, and
then went off. I looked around under the
hood and saw nothing strange. I have not shorted the test plug to test the
system.
Hi Dan;
There is no adjustment screw for the TPS. You loosen the two screws that hold it to the
TB, rotate it on the TB and then tighten the screws. I have the full description of the testing
and adjustment procedure on my web page for your reference:
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
Which screw(s) were you adjusting? From the sounds of it you are adjusting the
bypass air screw on top of the throttle body.
This screw is used to adjust the idle speed. Also, you should pull the new check engine
trouble code and see what it says.
I would also test the O2 sensor, especially with the Bosch
sensor. While the Bosch O2 sensors are
good, I’ve heard of folks having trouble with them in Toyotas, Denso and NTK
sensors are most like OEM. You may have
had some bad gas in there, or even something as simple as having some silicone
sealant used that was not O2-sensor-safe.
This sensor has the most impact on gas mileage, unlike the TPS, which
will affect idle speed and throttle response a bit. The Factory Service Manual has the
instructions on testing the O2 sensor, but in a nutshell, you get the sensor
hot (2500 RPM for a few minutes) then use an analog voltmeter on a 1-volt scale
and observe that the needle twitches from near 0 to near 1 volt at least 8
times/second.
Note:
If you are searching for, building, modifying, or maintaining a Toyota 4WD truck, send your Truck Tech questions to Roger Brown at <TruckEditor@tlca.org>. I’ll try to answer your questions with authority!