RAV4 starting problems

[Geoff]

My daughter has a 2006 2.4lt petrol RAV4 with 110k on the clock

In recent months it has become hard to start , especially when hot

Once started the car performs faultlessly

The computer is not showing any faults and the web is not much help

The throttle body has been cleaned with only minor improvements

Im reluctant to take it to Toyota as this time an just throw $$$$ at it until I have some idea what is the solution

Has any one experienced this problem , if so how did u fix it ??

Tks

Geoff

[ambrose607]

Make yourself a plan. Take it for a drive to get it hot and bring it home. Turn it off and if it doesn't start call the NRMA. Most of them guys are pretty cluey. He might not be able to fix it but he will tell you what's wrong with it. That way if you need to take it to Toyota they won't be able to tell you a load of crap. I done the same thing when my CEL light came on. Called them and they told me it was an O2 sensor. It's somewhere to start and free if you are a member. As i said most of the guys are pretty smart

[Singers83]

Crank angle sensor??

[Fab1]

The crankshaft position sensor records how fast the crankshaft is spinning. This speed is then used by the cars internal computer for proper fuel injection and ignition. There are actually 2 parts to the sensor; a disc that rotates and the sensor which remains in place. The most typical type of sensor works off of the Hall Effect which uses a magnet. Many of the failure symptoms are similar to issues that other parts will have when they fail. Many times it can take several tries to uncover that it is the sensor that is the problem.

1 - Check Engine Light

This can be frustrating as the check engine light can turn on for many different things. Your mechanic will need to hook up to your cars internal computer to determine that the sensor has failed. Many times this light may go off when the car is running but when you start the car again after it has been off for a while the light has turned off. This occurs when the sensor stops working due to high heat levels. Once the vehicle cools down it will function again.

2 - Cylinder Misfiring

Only one of the cylinders needs to misfire to cause a problem. Many times misfiring is due to issues with the spark plug, but if the sensor fails then the computer is not getting the correct information on piston position. Many people will not check the sensor, but if you have fixed everything else and there are still problems you should check the sensor.

3 - Acceleration Hesitation

This is also similar to the cylinder misfiring. If there is some type of hesitation then the computer is not getting the correct information on the position of the cylinders when the car is running. There is a lag between the computer getting the information from the sensor so it takes the car a little bit of time to accelerate.

4 - Intermittent Starting

This is the most serious of the symptoms that could occur. When the sensor completely fails then the internal computer will have a malfunction code. If the car continues to have difficulty starting and you do not have it fixed then one day it will not start at all. Many times this type of failure is because there is a problem with the electrical connection. There may be a problem with the circuit. If the signal to the computer begins to fail then this can cause the spark plugs to fail and eventually damage the engine.

5 - Engine Vibrations

Once the sensor fails then the position is not monitored, so you may find that the engine starts to have very strong vibrations. This will in turn affect the engine power and can also stop the mileage from recording properly.

6 - Backfiring and Stalling

Your car may stall from time to time. Your car will start fine, but then stall after a time. It can stall a few seconds after starting or quite some time after starting. This goes the same for backfiring. You will notice that the car keeps backfiring frequently.

7 - Irregular Car Function

Basically you will notice that regular engine workings will start to become irregular, such as speed fluctuations, irregular acceleration, idling fluctuations, and more. If you start to notice a lot of odd and irregular workings then check the sensor.

ENGINE DIAGNOSIS

MAF FAILURE

1:Low gas mileage,shuddering,stalling,knocking,pinging.

2:CEL may come on.

CRANK SHAFT SENSOR

1:Engine may start normally in some cases,but will cut off after a few minutes(seconds) of operation.

2:Engine may not start at all.

3:No spark from the spark plugs.

4: Engine may backfire or have irregular rpms,if the vehicle starts at all.

5:Long cranking time when starting cold.

6:Engine may run rough on a intermittent basis,poor idle,poor acceleration,stumbling and/or hesitation.

7:Drop in mileage and stalling upon acceleration.

CAMSHAFT POSITION SENSOR

AS ABOVE.

TPS

1:A car that hesitates and stumbles during acceleration may have a faulty tps.

2: If your car idles unevenly or hesitates intermittently,regardless of acceleration,the tps may have a faulty or loose connection.

OXYGEN SENSOR

1:A sudden decrease in gas mileage.

2:Cell may illuminate.

3:Smog test failure usually means bad sensor.

4:Engine may idle roughly,hesitate,or stumble.A bad 02 sensor causes an engines air/fuel mixture to become too lean.Normally,a lean fuel/air mixture(too much air,not enough fuel)will cause a engine to miss,or misfire,especially when an engine is idling.

KNOCK SENSOR

1:CEL may flash.

2:If the knock sensor is not working properly you will most likely hear sounds emitting from the engine.

3: The vehicle will often shake or vibrate and misfire when the engine is started.

4:Stronger than normal burning smells due to the detonation in the cylinders.

5:Fuel economy is often affected,causing more frequent gas replenishment.

6:May have acceleration problems,such as dragging,hesitation or jerking from the engine during speed increases.

IGNITION COIL

1:Lack of spark at plugs.

2:The fuel injectors may fail to operate.

3: Rough idle may occur.

4:May cause engine stalling and an inability to accelerate smoothly.

SPARK PLUG WIRES

1:Rough engine idle and/or misfire.

2:Engine hesitation,which is normally most apparent during acceleration.

3:Engine power loss and/or surging.

IAC VALVE

1:A faulty iac will cause stalling problems at idle.

2:Most of the time if you hold the gas pedal down it will run fine.

These symptoms can also come from an EGR valve that is stuck open.

3: If you have a fast idle,check for an intake leak.

Hope this heps mate.

[Geoff]

Thanks guys for your reply especially Fab1

I will try to cover the points you raised but let me say again there are NO error codes appear when the computer is checked .

Ambrose607 I had not thought of the NRMA , will give that a try . The CEL light goes off along with all the other dash lights when the engine starts

Singers . Crank angle sensor. This is a possibility as if you try to start the motor by just cranking over you can sit there cranking all day & it will not start , however crank for a few seconds , off then on again , normally by the third or fourth time it will start

Fab1

**The problem is similar regardless of the engine temp so temp is not a factor

**Just recently the motor turns off just after starting , this has occurred 3 time over the past few weeks , You then need to go through the starting process again . Once in gear & driving it is OK

** There is no misfireing or acceleration hesitation . Once it starts the motor is 100% ok

** Intermittent starting . Which sensor are you refering to , the crank sensor ??

** Stalling . If you mean the engine just stops when in neutral , yes , as mentioned above , this is occasionally occurring

** Other than what I have mentioned , there are no irregular motor functions at this time

** MAF failure . Maybe but this component appears to be operational when the engine is running not when starting

** TPS , Oxygen sensor , Knock sensor , Ignition Coil & plug wires I think , at this time are all OK . It is a starting problem not a running problem

** IAC valve , maybe , will have it checked

EGR valve , this appears to more in use when the engine is running rather than starting

What are the possibilities that the problem is in the fuel system or with the Immobilizer??

Thanks again

Regards

Geoff

[Fab1]

Thanks guys for your reply especially Fab1

I will try to cover the points you raised but let me say again there are NO error codes appear when the computer is checked .

Ambrose607 I had not thought of the NRMA , will give that a try . The CEL light goes off along with all the other dash lights when the engine starts

Singers . Crank angle sensor. This is a possibility as if you try to start the motor by just cranking over you can sit there cranking all day & it will not start , however crank for a few seconds , off then on again , normally by the third or fourth time it will start

Fab1

**The problem is similar regardless of the engine temp so temp is not a factor

**Just recently the motor turns off just after starting , this has occurred 3 time over the past few weeks , You then need to go through the starting process again . Once in gear & driving it is OK

** There is no misfireing or acceleration hesitation . Once it starts the motor is 100% ok

** Intermittent starting . Which sensor are you refering to , the crank sensor ??

** Stalling . If you mean the engine just stops when in neutral , yes , as mentioned above , this is occasionally occurring

** Other than what I have mentioned , there are no irregular motor functions at this time

** MAF failure . Maybe but this component appears to be operational when the engine is running not when starting

** TPS , Oxygen sensor , Knock sensor , Ignition Coil & plug wires I think , at this time are all OK . It is a starting problem not a running problem

** IAC valve , maybe , will have it checked

EGR valve , this appears to more in use when the engine is running rather than starting

What are the possibilities that the problem is in the fuel system or with the Immobilizer??

Thanks again

Regards

Geoff

Some sensors including the crank/cam sensors won't illuminate the Cel until they are failing fairly bad.

A failing fuel pump will give similar symptoms your having.

The immobiliser could be malfunctioning also.

Just remember some codes/faults don't show until the sensors have deteriated to a certain degree and before then you will get weird drivability issues like your having.

In all honesty get yourself a reliable mechanic to check it over for you as there's a whole host of things that could be causing your issue and intermittent faults are the worse to diagnose unless you are prepared to sit there with a multimeter and a workshop manual testing each sensor.

Just thinking I had a similar issue on a car I did a few years ago and after hours spent searching for the culprit it turned out to be a bad relay(Burnt contacts)

The last thing you want to do is throw parts at it as that gets expensive real quick.

Cheers.

[The Incredible Hull]

Geoff, go have the injectors cleaned. Last time I did it on my car, which was many years ago now, the mechanic charged around $150, might be a bit more these days.

[Geoff]

Injectors , possibly but if they were playing up I suspect the engine would be running rough. Currently , this is not the case

Fab1 , yr comment " Just remember some codes/faults don't show until the sensors have deteriated to a certain degree " is well worth keeping in mind

From all yr information I think it comes down to 6 options

Fuel pump . I had a similar problem on occusions with a VS Holden some years ago . This is easy to check , ie turn on the ignition a listen to see if the pump is running

Idle Air Control (IAC)

Crank Sensor

Throttle Position Sensor (TPS)

Mass Air Flow Sensor (MAF) Possible but unlikely

Immobilizer

My mechanic is very cluey but with out any code showing on the scanner he is reluctant to start replacing parts which could run into a lot of $$$$ before the faulty part is found

I will speak with him today however , as I am going away for a few weeks may not have time to get the car fixed until I get back

Regards

Geoff

[The Incredible Hull]

Injectors , possibly but if they were playing up I suspect the engine would be running rough. Currently , this is not the case

Because you don't have any fault codes to work with, unfortunately all you can do is start to narrow down the problem.

It does sound like you have some sort of a fuel problem and cleaning injectors is one of the cheapest items to tick off.

Let us know how it goes.

PS. What sort of fuel is in the tank? Fill it up with 98 and see if that makes a difference.

[mako2000]

Geoff, first place to start is have someone put a fuel pressure guage on it, it sounds like you have a weak pump hence the taking a couple of turns to get it going. It should have about 40lb of pressure within a couple of seconds of turning the ignition on.

.Second thought, have the battery tested, and make sure the connections are tight and clean they can do weird stuff sometimes with starting on the Toyotas.

Edited January 19, 2016 by mako2000

[Geoff]

Thanks Mako . The fuel pump is currently No. one on the list followed by the crank sensor , a distant third is the Immoblizer .

[Geoff]

A proper test is the correct thing to do but there is a way to check if there is a pressure problem , turn to ignition on , wait 10 - 12 seconds then crank .

I've tried that & it makes no difference

[mako2000]

Not necessarily, A leaking regulator or slow pump will still not give the required pressure. Most pumps only run a few seconds once the ignition is turned on so leaving it on between 3 and 12 seconds isn't going to make any difference. Had the battery tested yet?

[Geoff]

Thought u might be interested in some feedback

I found the problem . The chip in the ignition key was faulty , working some times then not others . By turning the ignition on then off 3 or 4 times finally activated the chip there by turning off the imobliser & the car started

Ambrose 607 was on the money with the NRMA

A strange thing occurred , I unlocked the car , placed the keys on the front seat started to walk away & heard a click , the car had locked it's self , called the NRMA , the guy had the door open in a few minuits , I asked about the starting problem , he checked the spark , nothing , checked the imobilser was still active .

He was 99% sure it was the key , gave me a name & number of a lock smith , I called , the guy arrived & about 10 min & $160 later all was fixed

I now have a happy daughter

[The Incredible Hull]

Good to hear Geoff.

The auto locking I think is quiet normal. When you lock the car with the remote, then unlock it, it will automatically lock within a minute or two.

It varies from car to car, the newer cars are smarter and can detect the key, old cars not so smart.