pistonbroke31

Rav4 Hot start problem

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Hi Guys , I have a problem with my wifes 2005 Rav4 XT4 D4D as follows: The car starts when cold, albeit after 10 seconds of cranking and a gradual firing up and once started runs as well as it ever has. The problem i have is that if you stop, say for fuel, after the engine has reached normal running temperature, and go to restart the engine it will not fire up. The engine cranks over ok, but will not fire up. If you walk away and leave it for about 20 minutes, it will then restart ok. I would say that the Battery and starter motor are both alright judging by the speed it turns over, but refuses to fire up regardless of how you use the throttle pedal when trying to restart the engine. If i restart the engine before it reaches operating temperature, it starts fine, its only trying to restart the engine when it has warmed up. any help you guys can offer me would be gratefully received. regards Dave

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You have two symptoms here:

10 seconds cold cranking, this is way too long & Non start when hot, Possible causes taken from Toyota's diagnostic flow chart for hot/cold starting issues:

1. Starter signal circuit / Starter / Battery ( see below )

2. Injectors ( see below )

3. Fuel filter ( not usually issue so long as it changed every 40k/4yr unless there is fuel sludging ) 

4. Compression ( never seen a worn out one )

5. Engine ECU ( unlikely )

6. Supply pump / SCV ( pump is unlikely, SCV's possible but usually give hesitation when running and fault codes )

7. Fuel pressure sensor/ Coolant temp sensor ( unlikely )

8. Intake Shutter ( unlikely )

9. Glow Plugs  (discount for hot start issues, usually give fault codes )

 From the above I have seen:

Starter motor issues are not unheard of on the 2.0 1CD engines basically over time debris builds up inside the starter casing this eventually starts to build up around the starter spindle slowing the spindle speed enough to cause slower than normal cranking speeds which is worse when hot as the spindle expands and sticks even more as the engine gets hotter. Sometimes removing and cleaning/lubricating the starter works however if it has been going on for a while the spindle is usually too damaged  and a new starter is required.

I have also seen hot starting issues being caused by leaking injectors, this is not usually an issue when cold as the cold start requires a rich fuel mix however when trying to restart the mixture is too rich and the car will not restart until cools down again. Normal diagnostics don't normally spot injector leaks when the engine is off the only reliable way to check is gto remove the injectors and give them to a diesel injection specialist who can pressure up the inactive injectors and see if they hold pressure or if they drip fuel, if they drip then its a new injector.

 

 

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You need to do some simple tests....

When it doesn't start, will it start with a bit of easystart / butane / solvent etc sprayed up the intake airbox?

Get some kind of OBD2 scanner which shows you live data, then when starting you need to watch for values:-
1) engine speed
2) MAF airflow
3) Fuel Pressure

Both symptoms - reluctant starting, albeit non stating when hot, and poor starting when cold are most likely caused by the same item.
If I was to randomly guess, I would suggest you might have a reluctant crank sensor or TDC/Cam sensor, they often get worse when hot.

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On 11/30/2018 at 11:43 PM, Devon Aygo said:

You have two symptoms here:

10 seconds cold cranking, this is way too long & Non start when hot, Possible causes taken from Toyota's diagnostic flow chart for hot/cold starting issues:

1. Starter signal circuit / Starter / Battery ( see below )

2. Injectors ( see below ) 

3. Fuel filter ( not usually issue so long as it changed every 40k/4yr unless there is fuel sludging ) 

4. Compression ( never seen a worn out one )

5. Engine ECU ( unlikely )

6. Supply pump / SCV ( pump is unlikely, SCV's possible but usually give hesitation when running and fault codes )

7. Fuel pressure sensor/ Coolant temp sensor ( unlikely )

8. Intake Shutter ( unlikely )

9. Glow Plugs  (discount for hot start issues, usually give fault codes )

 From the above I have seen:

Starter motor issues are not unheard of on the 2.0 1CD engines basically over time debris builds up inside the starter casing this eventually starts to build up around the starter spindle slowing the spindle speed enough to cause slower than normal cranking speeds which is worse when hot as the spindle expands and sticks even more as the engine gets hotter. Sometimes removing and cleaning/lubricating the starter works however if it has been going on for a while the spindle is usually too damaged  and a new starter is required.

I have also seen hot starting issues being caused by leaking injectors, this is not usually an issue when cold as the cold start requires a rich fuel mix however when trying to restart the mixture is too rich and the car will not restart until cools down again. Normal diagnostics don't normally spot injector leaks when the engine is off the only reliable way to check is gto remove the injectors and give them to a diesel injection specialist who can pressure up the inactive injectors and see if they hold pressure or if they drip fuel, if they drip then its a new injector.

 

 

Many thanks to Matt and Lee for your responses to my problem, just to put you guys in the frame, the story has moved on a bit since. I had taken the car to my local garage who i trust implicitly, and they looked at the car but could not come up with a definate diagnosis, but did say that fuel pressure was showing a bit low and suggested taking the car to a specialist diesel garage, so the owner and myself delivered it ourselves, and told the garage owner to diagnose the problem and give one of us a call so we could decide how to proceed. We heard nothing for seven days or so, then my garage had a call to say that they had removed all the injectors, which had taken them five hours, due to stubborn injector removal and having to remove camshafts and housing to get the sealing washers out. they then said they had all 4 of the injectors tested at £25 each (£100), and that all 4 are bad and would need to be replaced. This work has been carried out without my authorization, so how do i stand with that. As I work in a shop i have 1or 2 mechanics come in, and after a chat with one of these guys, he said if all 4 were bad, the car would not run normally once it had started. I was then talking to another guy who i know quite well, who has a friend who is in the motor trade, and who buys and sells cars, and could be interested in mine, and he has a good friend who works at Bosch on diesel fuel system repairs, who he contacted and was told that no way would it be 4 bad injectors, he had recently sorted out an avensis with the same engine, and exactly the same problem, and it turned out to be the injector pump needed to be re programmed. I am going to chat with my local garage tomorrow and see how he feels about it. I also found out through a local contact that the injectors have not been tested at the nearest possible place to the diesel specialst, which i would have thought would make sense. Sorry to waffle on with this thread, but i thought you would need to know the whole story before you can advise me on the problem.

So, do you feel that the problem would be 4 bad injectors, if so how would the car run if it were.  I plan to ask them where they got the injectors tested, so shall i ask for the so called bad injectors back and have them tested myself. I have no plan to be paying them for the work i did not authorize, but my car is in pieces on their property so they hold all the cards at the moment.

 Some advise from you guys on this forum would be invaluable to me at this trying time.

Regards Dave

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I would suggest you are in a the typical scenario of the blind leading the blind!

People are making stab in the dark guesses to solve your issue.

If its a pump problem, or a learnt values problem, or SCV valve issue, the fuel pressure value in the live data would tell you this - e.g. target v's actual pressure.

If it's an injector leaking problem then the same target v's actual pressure value will tell you this.

We have ODB2 diagnostics with measuring blocks/live data for this exact purpose..... but no they'll take your vehicle apart instead 😱

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Hi Matt

Thanks again for responding, so the injectors can all be checked while they are still in situ and there was no need to remove them at all is that correct? It is ridiculous that they removed them at all, obviously it is a money making scheme. I suppose it is possible that they may not have removed them at all, found another problem, resolved that, and are just looking to rip me off. I shall be going up there this week hopefully with my mechanic to talk to them, and i will have a look under the bonnet to see what they have removed, and ask them why. If the values of the injectors were incorrect on the obd2, would they then have to remove them to get them checked, or would the read out be conclusive?

Regards Dave

 

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I don't think this is sinister, I just think it's plain incompetence.
Every time I send injectors away for testing they always tell me they are defective - trouble is 10k miles after you fit new injectors they no longer perform like a new injector, thus out of spec, thus defective.

It's pretty standard procedure in most garages, take injectors out, send for testing.

Injectors checked in situ... well there are live correction values so you can see weak ones and over fuelling ones - you also listen to them with a stethoscope,  a good guy knows what good and bad injectors sound like. It doesn't give exact test figures like bench flow testing but has served many well so far!

Keep in mind I bought my Rav4 from a Toyota main dealership, and they had spent a fair chunk of customers money on it and they couldn't make it run! So main dealer or back street garage, they are all as useless as each other. Doesn't help when garage staff wages are £15k to £30k a year - a decent diagnostic technician knows they can get £50k to £100k+ working self employed.

If they can fix it great, but it depends how convoluted of a route it takes them to get there. If I need tyres, brakes, exhausts, suspension bits I use a "garage". If you need something complex fixing find an Auto electrical diagnostics specialist.

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The fact is that the you state that the car generally runs as well as it has ever done. This would tend to rule out several potential problems. All cars are subject to wear and tear and if you removed the injectors for testing on any car with a fair mileage - the injectors would not meet original spec. Dripping injectors can cause hot starting problems and the injector testing outfit should report back on exactly what the issue is with the injectors. Unless there's some supporting evidence, there's little justification in the expense of removing and rig testing injectors in the first place.

The problem you describe has come up many times on this forum and in many cases has been been associated with Battery, starter motor, cables or bad / dirty connections. Although it may sound OK - the starter motor needs to exceed a certain speed before the engine will start and often performance is restored when the motor cools down. It's quite easy to measure the cranking speed, current draw and motor terminal voltage with the engine cold and hot in order to confirm / rule out the starter system. It's worth bottoming out the starter system before embarking on other potentially expensive options.

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