High Idle petrol 120

[Jon Avid PP Poster! Find all posts View Profile Close Jon]

Have set one of the readouts to measure manifold air pressure(vacuum).
There are no readings shown, just a blank space then MAP.
This seems that the sensor is not sending a signal.
Now to locate it and check it.

[TBPrado Junior Member Find all posts View Profile Close TBPrado]

Your readings on your last post are normal.
The MAP reading won't show anything for the v6's. A feature used for the D4D's boys and girls from my understanding.

What are the coolant temp readings showing? Mine shows around 85 degrees in normal conditions. Just thought this might be a possibility as the car would most likely use this to maintain high idle until the engine is warmed up.

Might be worthwhile to start searching this site:
http://www.tacomaworld.com/forum/2nd...high-idle.html

[Jon Avid PP Poster! Find all posts View Profile Close Jon]

The coolant temp on the scanguage was about the 83 degrees mark.
Previous pasts have suggested there may be a vacuum leak in the manifold.
Still need to locate the water temp sensor..

[Bear63 Senior Member Find all posts View Profile Close Bear63]

Might be a stupid question but what condition the battery in ? I don't know how many weird problems i have had with vehicles that have been traced to a battery on the way out (and yes they have passed all the usual tests shortly before they fail completely) Including my car which used to misfire when it was cold

[SWR Banned Find all posts View Profile Close SWR]

Gday Jon

The water temp sensor is at the very back of the engine where the by-pass housing links both of the cylinder heads together. you will see the sensor there where the water hose for the cabin heater clips on.

Follow the top hose from the cabin heater (Passenger side fire-wall under the bonnet) and it will lead you to the water temp sensor

2009 TOYOTA PRADO (GRJ120 = 1GRFE).

WATER TEMPERATURE SENSOR = Part No: 89422-33030

Engine coolant temp sensor:
2.32 to 2.59K ohms @ 20cel
0.310 to 0.326k ohms @ 80cel

Cheers

[Jon Avid PP Poster! Find all posts View Profile Close Jon]

Had a look for the water temp sensor today...what a mongrel place to put it, really difficult to get to and test it without dismantling the intake assembly..

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

I think you'll find both diesel and petrol engines have the MAP sensor, this sensor is used to
to firstly detect the atmospheric air pressure at start, ie if your cars at see level or on top
of a mountian, this info is used to adjust the fuel air ratio.

Once engine is started if engine doesn't have a MAF sensor the MAP can be used to work out
the engine fuel requirements.

If your engine has a MAF and the V6 does the MAF sensor is used to work out fuel requirements
so MAP is not needed once engine is running and maybe why it doesn't show.

Cheers
Leigh

[Jon Avid PP Poster! Find all posts View Profile Close Jon]

Thanks Leigh.

As the Scanguage seems to indicate the correct temperature, I have not checked the water temp sensor, as it is really difficult to get to.
After checking the Tacoma forum, It was suggested to disconnect the battery terminals and shorting them together.
I disconnected the cable from the positive terminal and used a multimeter on DC volts to discharge the ECU capacitor by putting one probe on the positive cable and the other on the negative battery terminal.
Reset everything and drove to the 4WD show.
Found the RPM sat on about 1500+ RPM for a couple of Km, then dropped down to the (abnormal) 1200 RPM above the 40KPH mark.
I still think there is a sensor somewhere that is faulty, however not enough to trigger an engine fault code.
What I would like to do is to test all the inputs to the ECU, at the ECU. I feel that I would need to know what the inputs should be, may need a 'scope to check, especially the speed sensors.

[Bear63 Senior Member Find all posts View Profile Close Bear63]

The steps i would do to diagnose this problem are ,full diagnostic scan on all systems and make sure all readiness tests are completed ,test the battery(age etc),charge and earth circuits with an oscilloscope (takes about 15 minutes to do)and also physically check the maf for cleanliness,air cleaner ducting for security ,throttle body cleanliness then you work off from there

[Jon Avid PP Poster! Find all posts View Profile Close Jon]

Yes, I will need to find someone in Sydney that can 'scope out and scan all the diagnostic systems.
I have checked the battery, the throttle body and MAF has been replaced, No obvious vacuum leaks, Water temp goes up to normal range. Checked and cleaned all plugs/sockets in engine bay. Checked and fixed high resistance on crimp connection on negative battery cable. Problem seemed to occur after fitment of snorkel.
The Tacoma forum also has instances of the same problem, after work was done on the engine.

In summary, the problem occurs when:

The vehicle speed is above 40Kmh
The inlet air temp is below 35 deg
EGT is at open loop

It does not occur when:
Inlet air is above 36 degrees

It is worse when:
The MAF is cleaned and not allowed to dry properly
After 'power down' reset

The common theme seems to be the MAF inputs, as this monitors the air flow and temperature. I may need to change this again.

[SWR Banned Find all posts View Profile Close SWR]

Gday Jon

I think we need to pretend that the scan gauge don't exists and we do it the old school way! (Which is harder and takes longer but you change less parts).

Keep your digital Fluke close at hand! Teh heh.

Update: confirmed that you have checked as follows:

The battery,
Throttle body replaced,
throttle position sensor replaced,
MAF replaced,
No obvious vacuum leaks,.. Maybe?
Water temp goes up to normal range,
Checked and cleaned all plugs/sockets in engine bay,
Checked and fixed high resistance on crimp connection on negative battery cable.

The other items that you can eliminate in a preferred order are as follows:

You said the problem started after fitting a dual battery system and a snorkel so i am guessing they removed the air filter box.

There "is" a vacuum hose that connects to the air filter box that has to be removed as well as the MAF sensor plug.... Can you confirm that there is a vacuum hose connected to the air filter box? (Don't ask me where exactly as diagrammed is vague as all hell but it is there!)... Guessing towards the fire wall on the same half of the air box that the MAF sensor is on!

Also! According to wiring diagram there is 2 x Heated oxygen sensor's "and" 2 x Air fuel sensor's which are probes on both left and right exhaust bank systems.

#1 - Air fuel sensor A46 (Bank 1 sensor 1) - Upper exhaust extractor. (89467-35110 = $99.81 from UEA or $150.82 Japan).
#2 - Air fuel sensor A47 (Bank 2 sensor 1) - Upper exhaust extractor. (89467-35110 = $99.81 from UEA or $150.82 Japan).
#3 - Heated oxygen sensor H20 (Bank 1 sensor 2) Lower exhaust, bolts to extractors (89465-35670 = $64.47 Japan).
#4 - Heated oxygen sensor H21 (Bank 2 sensor 2) Lower exhaust, bolts to extractors (89465-35680 = $92.71 from UEA or $119.33 Japan).

NOTE: The above part numbers are for "09 model probes".... Warning: "03 model probes" has different resistances so different part numbers.

I reckon confirm the vacuum hose is connected to the air filter box then maybe focus on the probe sensors spec's

Cheers

[Bear63 Senior Member Find all posts View Profile Close Bear63]

Something i thought of today especially since the throttle body has been replaced is that the throttle body has coolant flowing though it and can easily get an airlock inside due to its position' this can affect its operation, can you slide one of the hoses off it with it running and make sure coolant is flowing though ok?

[Jon Avid PP Poster! Find all posts View Profile Close Jon]

Thanks Bear63, will check it when I get a chance

[Jon Avid PP Poster! Find all posts View Profile Close Jon]

Today I removed the air filter box and checked it for any cracks or leaks. Nothing apparent. Vacuum hose was connected (I think this is the blocked air filter sensor), removed & cleaned the MAF sensor.
I then removed the throttle body and cleaned it. I removed one of the cooling hoses and there was water in it, so assume this is ok. Cleaned the MAF & throttle actuator plugs & sockets with contact cleaner. Checked all the other plugs & sockets; all the vaccuum hoses. Re-fitted the throttle body & ensured it opened & closed ok by having the ignition on & operating the throttle. Re-fitted the air filter box, vaccuum hoses, & MAF plug & inlet hose. Reset the ECU through the Scanguage.
Will do test drive tomorrow to see what happens

[SWR Banned Find all posts View Profile Close SWR]

Gday Jon

Just so that it makes it easier for other people as well as my self can you fill in you details on model/year auto or manual etc so that it makes it much easier to track parts and variants between models.

Reason why i ask is because the auto model has a few extra peripherals concerning the engine management controls.

EG: When logged into your account go to: "Settings" (top right) then on the bottom left of the page you will see a header called "My Settings".... Click on "Edit Signature" and fill in basic details of your vehicle sort of similar in detail to mine below so when asking for help or advice etc everyone knows what rig you are asking help or information on!

Once filled in basic details click on "Save Signature" then can log out

Cheers