Toyota Auris Hybrid Engine running rough and ratttling

[Brian Birch]

My wife came home from a short local journey and said that when stopped at a junction with her foot on the brake the engine revved on it's own a couple of times. The engine now runs very rough and rattles.  It was due for an MOT the next day so, suspecting a misfire, I bought a new set of spark plugs, which I didn't fit because you need a special plug socket. They were replaced by the garage prior to the emisssions test but the spark plugs didn't cure the rough running / rattling.  They ran diagnostics which did not show any errors. I have checked the coil packs which look good (the diagnostics should flag if they are faulty)  i eventually concluded that the only course of action was to take it to the local Toyota franchise because they are the "experts"  After 5 hours they phoned to tell me their diagnostics had not shown any errors. i gave them the go ahead to investigate further but said if they aren't sure what is wrong they need to speak to their technical support.  As they charge £125 an hour I need to get this fixed quickly.    I have looked on the internet for possible causes. The EGR valve and the MAF sensor are suggested but they are both monitored and failure will flag a diagnostic error.                                                                                                                                                                                                                                                                 As I am sure the problem was caused by the underlined /bold above.  I found only 1 thread that mentioned an "engine surge"  that suggested the timing chain retainer being loose.  Any suggestions as to what is causing this problem would be greatfully received.

   

[FROSTYBALLS]

Moved to the Auris club.

[furtula]

It could be possible the the tensioner was loose and chain skipped a bit, car was about to shut down when idling, so it  revved a bit to try to get to designated idle speed.

 I think on your model the chain tensioner should be spring loaded, and it's a tiny part on top of the engine, towards the driver, which is held on by 2 screws.

Here's a good demonstration of the location and how the tensioner works. 

https://youtu.be/iBfPxf-CDyE?t=145

 

[TonyHSD]

Hi, my diagnosis is a dirty throttle body, you have exactly the same symptoms plus when throttle body is dirty you almost never get a fault code. Same for the egr pipe, just get them both clean properly, there is a Map sensor next to the body , you can clean that too, plus remove any oil that you may have at the bottom of the intake manifold. Don’t forget to disconnect the negative of the 12v Battery before you start this job, when you do so and your boot doors is open you may want to cover the door lock with a towel in case you shut the door close so you can have access later, electronically operated lock, no power no door opening:) After all cleaning job is done start the car and leave it to finish heat up cycle, the ICE may pulsating meanwhile and a few times than after when stationary and running but this will settle and you will have no troubles. 

That guy have some helpful videos how to diy it. 

Good luck. 

 

 

[Gerg]

You have obviously spent some time thinking about this problem before posting on here.  You have likely discovered that at higher mileages (100,000+) these engines can sometimes suffer from blocked EGR coolers, EGR valves and inlet manifold EGR ports. And, perhaps as a result of the elevated combustion chamber temperatures that follow on from the restricted EGR flow (but this is still open to debate), the head gaskets can fail, probably accelerated by the pinking and even detonation that follows.   I was surprised that a malfunctioning EGR could do so much, but this Toyota engine version (high compression) seems a bit prone to it.

Hopefully, none of this is happening in yours.  So just the usual questions:-

How many miles has the car done?

Have you noticed any fall in the level of the engine coolant header tank (the one on the driver's side)?

Does the engine rattle only on acceleration, or at all times the petrol engine is running, hot, cold?

[Gerg]

....Forgot to mention, best not overlook the simple things!  Given the age of the car, the rattles could be an exhaust heat shield that has come loose through corrosion at its mounting points.  I appreciate that this won't make the car run rough, but it will sound like it's running badly.

[Brian Birch]

Thanks for all the responses to this problem. I guess in order of ease the first step is the throttle body then the EGR valve. If it's the chain tensioner then that's an engine out job (I'm told) which is too much for me. It's a long time since I worked on a car. (the last one was a MK1 Ford Capri 1600 GT spark plugs / points etc. no ECU or CAN busses)                                     TONYHSD    Why would I need to isolate the Battery to clean the throttle body. If it's part not  of the Hybrid control system is it not only 12v dc.?                                                                     I am going to the Toyota dealer first thing tomorrow.  If it's not fixed I will pay them off and get my tools out   

 

[Saxmaniac]

There's an American forum called Prius Chat that might be helpful though Gerg above has given good advice

[Gerg]

As Saxmaniac mentions above, there are excellent videos for doing most of the popular tasks on a Prius (i.e. by Nutz About Bolts).

The EGR system clean is straight forward but time-consuming,  It will involve leaning over to the upper rear of the engine, so not so good for the ol' back.  No special tools required beyond an unusual 'reverse-Torx' star-shaped socket for the far side of the EGR cooler pipe flange, and some dishwasher powder and a wine bottle cork to clean out the insides of the cooler (left overnight).  A hose clamp is useful to avoid draining much engine coolant.  I have yet to take one off (ours have low-ish miles), but I do have a spare, clean cooler to swap in, so that there is no rush to get the old cooler cleaned up. This is the longest part of the job otherwise.  A dealer will look to fit a new one instead at £200+ for the part, as they don't generally do the 'overnight cleaning' thing.  All the gaskets can be reused, as can the coolant if you are careful where you drain it.

No EGR circuit on a Capri 1600 GT, but then a Kent engine (early model? Not Pinto?) was quite simple, it only had about 9 moving parts, didn't it?  Three times that if you included the Weber carb.  So popular they named an island after it!

How many miles has the Auris done?

[TonyHSD]

Hi, I think Toyota will only take your money and help you nothing if the problem it’s not obvious. You can  check and clean the throttle body, MAF sensor and the intake manifold first, than clean the egr pipe at least and if the car is over 100k miles the cooler too. Check the exhaust mountings are all solid, no loose and doing so yourself you will make sure that all has been checked properly. Disconnect the 12v Battery is to reset the ECU so the car will operate as new(clean)  and will misbehave for a short time or will not at all, you can keep Battery connected, no problems. The mechanical work on those cars is pretty much same as on the ones from the past.

Good luck 

[Brian Birch]

Thank you all for your input into my problem.  I have attached a photgraph of the EGR valve which was the cause.  I didn't fix it myself, I gave the Toyota the go ahead as they said they weren't charging me for anything but the actual time it took to replace the valve.  In the attached photograph it is difficult to see but the valve is open. The question that is left unanswered is why did the diagnostics not pick up a EGR position error.  Before I retired I used to work on BIG industrial laser printers with many hall effect sensors which monitored the position of components. I guess this is how the EGR valve is monitored. The garage gave me the "dead" valve. I will clean it up and investigate as a matter of interest. Thank you all again for your advice.

 

[Gerg]

It's good to hear that this is resolved.

It would be interesting to see what difference this makes to your mpg.

I have lightly adjusted your photo to make the carbon deposits more evident. The next photo (not my picture) is of a Prius EGR with 120,000 miles on it that the owner has just started to clean up the central plunger.  The next one is the mouth of the EGR cooler from the same car also at 120,000miles.  And the last one is a clean cooler for comparison

If your symptoms show any sign of returning then maybe your culprit lies somewhere here.

By the way, did anyone get to ask, how many miles has your car done?

[Brian Birch]

I took the valve apart and the central plunger was seized.  The plunger is wound in by a what I would call a lead screw (see photos) driven by little motor in the plastic housing     Gave it a quick clean and a spray with GT85 and it freed up after a couple of goes at manually activating.                                                                I can't test it but I reckon it's probably OK. How it monitors the plunger position I don't know.

I should have said earlier the car has done 70,000miles.  

[Gerg]

Excellent that you took it to pieces and took some photos.

I'm no expert on these but, from your pictures I would reckon that you're looking at a conventional stepper motor without any sensors to feed back rotational or end-of-travel information.  Instead the Toyota designers have assumed the valve to be (say) fully out when the ECU is powered on, the ECU will then rotate the motor the maximum number of pulses (steps) for a 'full' reverse  (it knows this number because this is a value already coded in the ECU) so as to close the valve. 

Even if the valve was already closed or part-closed, the unnecessary stepper motor pulses will do no harm, and assuming the valve is free (so, not your one), then the ECU now knows that the motor is closed, and has a reference point for all subsequent motor movements.  If the valve is then opened by a set number of motor pulses, it will know by how much it is then open.  That is, until the ECU is powered down, when it all re-references again.

Which is all fine until it jams and there is no 'sense' information going back to the ECU to say so.

That's my theory, anyway.

It looks like the motor would go back together easily enough, so a potential saving if you didn't want to buy a new one and you're happy it's been lubed-up OK.

[Brian Birch]

I used to work with stepper motors, but 10 times that size. It was a while back and memory is dimming with age. The garage person said they usually take the settings from the old motor and use them for the new part but because it was seized they couldn't. As you noted above Gerg they said the car will misbehave a bit until it resets the parameters. (it is revving a bit higher than normal when it kicks in)

[Gerg]

A very long time ago, I was involved with some Xerox 4090s, IBM 3825 (Kodak engine?), 3800s and a vast, old, Swedish, IBM impact printer (number???) that was the length of a Winnebago, almost.  But only until I managed to flee the company!  Perhaps you remember them?  I try not to.  The stuff of nightmares for me! 

But yes, I don't remember them using a stepper motor without an optical sensor/timing fence of some type.

Oh!, and four large IBM lasers (3827/3829?) at VW GB at Blakelands, MK.  I hated those ones the most!!!!

[Brian Birch]

25 years fixing Siemens lasers ND2  / ND3 / NDx / NDZ. For me the hardest machines in the IT industry to fix.  If you can fix them you can fix anything..When I joined in 1985 we took over the high volume printing in th UK.. I used to enjoy seeing IBM technicians walking into a print room to a machine that they had no idea which end was which. Fixing Laser printers could be damned hard work.