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Discussion Starter · #1 ·
Hi Everyone,

I'm having a problem with my 2007 Rav 4. It has the 2.0 engine (1AZFE). I have a problem no one can solve even the dealer.
It gives me a hard start when warm - it either cuts off on the 1st start or takes a few seconds than normal to start.
I do not get the problem when the car is hot - if I stop for a few minutes or if the car is left overnight. The car is showing signs of over fueling - like black spark plugs. I 've done the following work so far:
1. Clean the fuel filter
2. Recoated the gas tank
3. Changed the plugs
4. Serviced the injectors
5. Serviced the throttle body
6. Changed the throttle body
7. Changed the fuel pump
8. Changed the MAF sensor
9. Changed the fuel regulator

I tried starting the car in neutral; turning the ignition key from the off an on position several times and trying to start the with the gas cap off.

At this point I'm frustrated with this problem and not sure whats next.
 

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Discussion Starter · #2 ·
One more thing when I first noticed the problem after I had serviced the car - also the battery was a few months old. I still went ahead and the git a replacement battery as an overnight scan showed that that battery had a problem but the teh battery dealer said nothing was wrong with it but they changed it anywhere
 

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The black spark plugs are a definite indication of running too rich. That's likely due to a bad O2 sensor, the one in the manifold that sets the AFR.
 
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Discussion Starter · #4 ·
Thanks,

BTW none of the scans have ever picked up anything based on this forum I got the following suspects:

1. Crank sensor
2. CAM sensor
3. Battery (but for the reverse problem - hard start when cold r overnight)
4. O2 sensor

Should I buy all 3 sensors?
 

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Were all these parts replaced because they were bad or was this a shotgun diagnosis?

If the dealer did not find the problem it is because they didn't look hard enough or didn't care.

You have the 2.5, not 2.0

You actually removed the fuel tank and had it coated? Do you mean a liner was installed?

Were all the parts new that were installed? What brand?

I would connect a fuel pressure gauge and monitor the fuel pressure while it is acting up.
 

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Thanks,

BTW none of the scans have ever picked up anything based on this forum I got the following suspects:

1. Crank sensor
2. CAM sensor
3. Battery (but for the reverse problem - hard start when cold r overnight)
4. O2 sensor

Should I buy all 3 sensors?
Unless you are determined to make a new car out of your RAV4 by eventually replacing everything :doh: why not replace the part that sets the air/fuel ratio, the O2 sensor in the manifold.
 

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You have the 2.5, not 2.0
In the USA it would be a 2.4l. The 2.5l came about in 2009.
Since the OP is NOT in the USA it could very well be the 2.0l engine.
 

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Discussion Starter · #9 ·
It was a shotgun troubleshooting as no one cannot find the cause.

Yes at this point i feel like I'm chaning every possible part. I did try to get a second and third opinion but so far its not panning out. As i mentionef above none of the scans show any error and the only real sign is thats its overfueling - this what someone told me when they did a 'live' scan and looked at the fuel trim.
 

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It gives me a hard start when warm.
I do not get the problem when the car is hot - if I stop for a few minutes or if the car is left overnight. The car is showing signs of over fueling - like black spark plugs.
You have no problem with a cold morning start, and you have no problem if you stop for a few minutes (say to run into a store), but you have problems when it is warm. Can you describe what "warm" means to you?

I don't know how frequently the situation of "warm start" occurs, but I don't think an occasional slow startup would be enough to foul the plugs. That would indicate a continuous problem with fuel mixture.

So if your plugs are black, then it might be easier to troubleshoot that problem and the solution may also clear your slow "warm" start problem.

How does the engine run, once it is started, is it smooth and runs at the normal idle speed? How is your gas mileage? Any clouds of smoke from your tailpipe when running wide open under a load?.

Despite having said that the black plugs indicate a mixture problem, the O2 sensors are very good at detecting faulty mixtures, and yet they have not indicated a problem. The same for all the other sensors you mentioned, they all have various methods for detecting faults in their operation.

For example if the VSS (vehicle speed sensor) indicates you are doing 100MPH and the TPS (Throttle position sensor) says your foot is to the floor, and MAF (mass airflow sensor) says there is no air flow into the engine, the ECU will determine the MAF is defective and light up the check engine light. Similarly in your case the B1S1 would be used to set the correct A/F mixture, and if it was faulty the incorrect A/F would be detected by the B1S2 sensor.

I also suggest getting an OBDII scanner that displays live data and verify that the fuel trim is continuously changing as you drive.
 

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I also suggest getting an OBDII scanner that displays live data and verify that the fuel trim is continuously changing as you drive.
Like the one in
.

If the mixture is actually rich it will start and run best when the engine is cold or cool and get much worse when heated up to normal. If bad enough the exhaust pipe could be black.

Overall it sounds to me like you're dealing with inept techs.
 

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Discussion Starter · #12 ·
The problem happens if the car is parked up over 30 minutes to about 5 or 6 hours. I get to work around 7 and if i do not use the car until 5 its fine. If i use the car anytime between that like lunch i sm nearly sure to always get the problem.
The problem manifests itself in 1 of 2 ways:

1. On first start it cuts off and then starts on the 2nd attempt.

2. It takes a longer them normal before it tumbles.
 

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That was probably a very expensive tester, but the constant auto ranging made it difficult to interpret. My relatively cheap scanner just displays the voltage digitally. In the V6 engine it is handy to compare the B1 and B2 readings when looking for a sensor problem.
 

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A rich mixture at startup could be caused by gas getting into the cylinder via a leaky injector, or it could be caused by a lack of airflow through the idle air control (IAC).

Try starting the engine with the accelerator held to the floor. This will signal the ECU to not inject any additional fuel, and it will also allow more air through the throttle body.
 

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Tried that and it seemed to work. What do this mean?
The procedure is used for starting a flooded engine. If it helped you, then it eliminates many other causes, particularly electronic problems.But we still need to know if your engine has a flooding issue all the time, or just at a very limited temperature range during starting that you described.

If you were to answer the questions previously asked in post #10, it could help to narrow down the problem.
 

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Discussion Starter · #18 ·
The engine runs fine normally and on the open road. It idles fine. There is no evidence of black smoke.


I'll have to borrow a scanner and do the test drive.
 

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The engine runs fine normally and on the open road. It idles fine. There is no evidence of black smoke.
Based on that information, we are looking for problem that affects the engine only during starting.

Try pressing the pedal just slightly, rather than all the way to the floor. This will allow the injectors to fire normally, but allow more air flow to increase the A/F ratio.

If that helps to provide normal starting I suspect an idle air controller (IAC) that may get stuck at certain temperatures. Or it may be a dirty throttle body that prevents enough air to pass at idle.
 
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