Idle Eratic D4d Yaris - Solution

[dustyhog]

Hi All,

My 2003 1.4 D4D started to idle eratic (up and down) and also became 'jerky' when running. Read lots of posts, spoke to local garage and even tried recon MAF with no success - then found solution from BobHT on this yaris forum. I have included below incase you can't find easy. Must be an issue as mine has onlt 30,000 on clock but an air hole (quite large) was completely blocked.

Also note that I first tried just removing the rubber hose from the top of the throttle body - I think thats what it is called. But unless you remove it completely you can't see the blocked air hole on the bottom - at first look you would not even know there was a air hole.

Quite a quick job so worth a try as it does not cost any money.

Thanks to Bob and his post (copied below) as it was spot on:- (saved me visting Toyota)

-----------------------------------------------------------------

Many thanks to all those who advised me. Its cured now.

Symptoms: Lumpy tickover when cold, it sort of hunts up and down and feels like its going to stall. When warm just slightly lumpy tickover.

Cure: When looking at the engine from the front of the car, on the left there is a shiny bronze vaccuum advance/!Removed! thing at the front of the engine. This is connected to a casting that is held to the front of the engine by four 12mm bolts. This same casting also holds the dipstick securing plate and part of the wiring loom (with 10mm bolts). It has a 2 inch diamater short hose going to its top from the air cooler that sits on top of the engine.

ONE Undo and remove the hose from the air cooler - may need to loosten the air cooler first (I did).

TWO Undo the 10mm bolts that hold the dipstick and the wiring loom to the casting.

THREE Undo all the 12mm bolts. You are dealing with aluminium, so undo all bolts a bit at a time to avoid distorting anything (same applies when re-fitting)

FOUR Take off the casting.

Look in the casting - mine was really full of carbon so that an internal air-way was virtually blocked. Clean all this crap out anyway you like.

Also, clean out any carbon in the manifold - i.e. look into the engine block and clean out the crud you can reach with a rag.

Re-build it all, then marvel at your tickover returning to its as-new sound. Nice.

Splendid. Hopefully that'll last another 40,000 / 50,000 miles or so.

It took about an hour and a half.

Cheers all and good luck. Back to smooth motoring and 70 mpg.

Bob

------------------------------------------------------------

[gar]

Hi All,

My 2003 1.4 D4D started to idle eratic (up and down) and also became 'jerky' when running. Read lots of posts, spoke to local garage and even tried recon MAF with no success - then found solution from BobHT on this yaris forum. I have included below incase you can't find easy. Must be an issue as mine has onlt 30,000 on clock but an air hole (quite large) was completely blocked.

Also note that I first tried just removing the rubber hose from the top of the throttle body - I think thats what it is called. But unless you remove it completely you can't see the blocked air hole on the bottom - at first look you would not even know there was a air hole.

Quite a quick job so worth a try as it does not cost any money.

Thanks to Bob and his post (copied below) as it was spot on:- (saved me visting Toyota)

-----------------------------------------------------------------

Many thanks to all those who advised me. Its cured now.

Symptoms: Lumpy tickover when cold, it sort of hunts up and down and feels like its going to stall. When warm just slightly lumpy tickover.

Cure: When looking at the engine from the front of the car, on the left there is a shiny bronze vaccuum advance/!Removed! thing at the front of the engine. This is connected to a casting that is held to the front of the engine by four 12mm bolts. This same casting also holds the dipstick securing plate and part of the wiring loom (with 10mm bolts). It has a 2 inch diamater short hose going to its top from the air cooler that sits on top of the engine.

ONE Undo and remove the hose from the air cooler - may need to loosten the air cooler first (I did).

TWO Undo the 10mm bolts that hold the dipstick and the wiring loom to the casting.

THREE Undo all the 12mm bolts. You are dealing with aluminium, so undo all bolts a bit at a time to avoid distorting anything (same applies when re-fitting)

FOUR Take off the casting.

Look in the casting - mine was really full of carbon so that an internal air-way was virtually blocked. Clean all this crap out anyway you like.

Also, clean out any carbon in the manifold - i.e. look into the engine block and clean out the crud you can reach with a rag.

Re-build it all, then marvel at your tickover returning to its as-new sound. Nice.

Splendid. Hopefully that'll last another 40,000 / 50,000 miles or so.

It took about an hour and a half.

Cheers all and good luck. Back to smooth motoring and 70 mpg.

Bob

------------------------------------------------------------

Hi, read this, does it apply to the petrol models, though?

I would kinda expect a diesel to choke up a bit more than a petrol as they smoke like a kipper factory on overtime, when pulling away!

[Chiro toyota]

Well Bob thats brilliant, just clean out 53 plate out, now smooth tick over. The internal airway was completely blocked. lots of cold running I guess, as my daughter has learned to drive in it last year.

Many thanks again

Tom

My 2003 1.4 D4D started to idle eratic (up and down) and also became 'jerky' when running. Read lots of posts, spoke to local garage and even tried recon MAF with no success - then found solution from BobHT on this yaris forum. I have included below incase you can't find easy. Must be an issue as mine has onlt 30,000 on clock but an air hole (quite large) was completely blocked.

Also note that I first tried just removing the rubber hose from the top of the throttle body - I think thats what it is called. But unless you remove it completely you can't see the blocked air hole on the bottom - at first look you would not even know there was a air hole.

Quite a quick job so worth a try as it does not cost any money.

Thanks to Bob and his post (copied below) as it was spot on:- (saved me visting Toyota)

-----------------------------------------------------------------

Many thanks to all those who advised me. Its cured now.

Symptoms: Lumpy tickover when cold, it sort of hunts up and down and feels like its going to stall. When warm just slightly lumpy tickover.

Cure: When looking at the engine from the front of the car, on the left there is a shiny bronze vaccuum advance/!Removed! thing at the front of the engine. This is connected to a casting that is held to the front of the engine by four 12mm bolts. This same casting also holds the dipstick securing plate and part of the wiring loom (with 10mm bolts). It has a 2 inch diamater short hose going to its top from the air cooler that sits on top of the engine.

ONE Undo and remove the hose from the air cooler - may need to loosten the air cooler first (I did).

TWO Undo the 10mm bolts that hold the dipstick and the wiring loom to the casting.

THREE Undo all the 12mm bolts. You are dealing with aluminium, so undo all bolts a bit at a time to avoid distorting anything (same applies when re-fitting)

FOUR Take off the casting.

Look in the casting - mine was really full of carbon so that an internal air-way was virtually blocked. Clean all this crap out anyway you like.

Also, clean out any carbon in the manifold - i.e. look into the engine block and clean out the crud you can reach with a rag.

Re-build it all, then marvel at your tickover returning to its as-new sound. Nice.

Splendid. Hopefully that'll last another 40,000 / 50,000 miles or so.

It took about an hour and a half.

Cheers all and good luck. Back to smooth motoring and 70 mpg.

Bob

------------------------------------------------------------

[Cyker]

Is there anything that can be done to mitigate this from happening?

The tip about giving it a good blast on the motorway now and then worked for me for keep the injectors from getting crudded up*; Will that help for this too?

* Well, I'm assuming it did as I haven't noticed the powerloss I was getting when I first got the car and was hypermiling it all the time :D

[carlowlad]

I just give it some welly once a week for a minute or two. Smokes a bit but then runs clear. I still think i should have a look as per the OP, just to be sure of it's condition. I may even post a picture of it!

[Madasafish]

Way to stop it happening?

Use high grade fuel with additives.

I use standard Shell diesel consistently - never had a problem. Car has done 41k miles mainly short distance.

Cheaper supermarket fuels with no additives make things much worse...

[Chris81]

Once again - does this only apply to diesel engines or petrol too?

[DONFRAMAC]

Once again - does this only apply to diesel engines or petrol too?

I bought a '53 reg Yaris D4-D, in Sept 2003, and treated it every 3 months to a dose of "FORTE" brand system cleaner. Used in the trade mostly, the 400 ml bottle treats 100 litres fuel (there is a petrol version also), it does a comprehensive job of cleaning all pipes, injectors, upper cylinders/valves, lambda probe, etc., ensuring clean-running, even cleaning EGR units, and decoking the top of the Cat. It costs £7.50p + VaT, at my Ford dealer, but I have seen it at twice that on the internet, and locally, in garages. You won't find it in car accessory shops. it does nothing to the cetane/octane rating, but will ensure clean emissions. An Avensis owner on this website used it on a high-mileage Audi A6, in 1/4 a tank of diesel, and that cleared the smoky exhaust, within a few miles, so it can be used for rapid effect. A friend of mine has, last month, used it on an LDV Convoy with 96,000 miles on it, with rapid and effective smoothing of the Ford Duratec 2.4 90 BHP engine it is fitted with. He has just left on a holiday to Italy with this Motorhome conversion, so I shall ask if the MPG was better than the 30 MPG he got driving it home 400 miles from Lincoln.

"FORTE" products are on a website, and include an engine-oil flush additive. eBay offers were regarded as a bit suspect, especially as the diesel version smells just like diesel.

Mercedes dealerships used this brand for many years, only recently changing to another.

I am now using the petrol version, with my Fiesta 1.25, and effects are not so immediately noticeable, but MPG is up by 2 for a while, and it runs sweet.

[carlowlad]

Once again - does this only apply to diesel engines or petrol too?

Yup! Diesels suffer the most from it. Petrols hardly ever see this issue.

[Craig69]

Thanks for posting this. Mine started doing running rough after 85k. I cleaned it all out today and its running much smoother. Its still cost me a bit though cos I managed to drop two sockets in the belly pan and can't get them out...

For anyone reading this and wondering how difficult it is - its not. I'm pretty much a muppet when it comes to things like this (see above) and I managed it in about an hour.

[Cyker]

Well if it's just sooting up due to low temps/incomplete combustion, I figure the same tricks to keep the injectors clean should help burn off all that carbon crap too...

I don't see how fuel cleaning additives can help clean the crud out if it's building up in the airways...

[Xana]

Well if it's just sooting up due to low temps/incomplete combustion, I figure the same tricks to keep the injectors clean should help burn off all that carbon crap too...

I don't see how fuel cleaning additives can help clean the crud out if it's building up in the airways...

That's the question, how can diesel additives clean the EGR ?

This makes no sense at all. Diesel is not in touch with EGR valve, so no way it can clean it.

[YarisTSpiritD4D55mark1]

Hi All,

My 2003 1.4 D4D started to idle eratic (up and down) and also became 'jerky' when running. Read lots of posts, spoke to local garage and even tried recon MAF with no success - then found solution from BobHT on this yaris forum. I have included below incase you can't find easy. Must be an issue as mine has onlt 30,000 on clock but an air hole (quite large) was completely blocked.

Also note that I first tried just removing the rubber hose from the top of the throttle body - I think thats what it is called. But unless you remove it completely you can't see the blocked air hole on the bottom - at first look you would not even know there was a air hole.

Quite a quick job so worth a try as it does not cost any money.

Thanks to Bob and his post (copied below) as it was spot on:- (saved me visting Toyota)

-----------------------------------------------------------------

Many thanks to all those who advised me. Its cured now.

Symptoms: Lumpy tickover when cold, it sort of hunts up and down and feels like its going to stall. When warm just slightly lumpy tickover.

Cure: When looking at the engine from the front of the car, on the left there is a shiny bronze vaccuum advance/!Removed! thing at the front of the engine. This is connected to a casting that is held to the front of the engine by four 12mm bolts. This same casting also holds the dipstick securing plate and part of the wiring loom (with 10mm bolts). It has a 2 inch diamater short hose going to its top from the air cooler that sits on top of the engine.

ONE Undo and remove the hose from the air cooler - may need to loosten the air cooler first (I did).

TWO Undo the 10mm bolts that hold the dipstick and the wiring loom to the casting.

THREE Undo all the 12mm bolts. You are dealing with aluminium, so undo all bolts a bit at a time to avoid distorting anything (same applies when re-fitting)

FOUR Take off the casting.

Look in the casting - mine was really full of carbon so that an internal air-way was virtually blocked. Clean all this crap out anyway you like.

Also, clean out any carbon in the manifold - i.e. look into the engine block and clean out the crud you can reach with a rag.

Re-build it all, then marvel at your tickover returning to its as-new sound. Nice.

Splendid. Hopefully that'll last another 40,000 / 50,000 miles or so.

It took about an hour and a half.

Cheers all and good luck. Back to smooth motoring and 70 mpg.

Bob

------------------------------------------------------------

I have just gone through the same procedure and the engine is so much livelier, like new. So I have uploaded 2 photos to assist anyone else in this predicament. The carbon built up in the orifice at the rear of the larger port reducing it from 12mm to 3mm diameter. After careful scraping, I could see that it links up with the smaller port. My D4D had done 38000 miles and always used top brand fuel.

[alfiejts]

Well if it's just sooting up due to low temps/incomplete combustion, I figure the same tricks to keep the injectors clean should help burn off all that carbon crap too...

I don't see how fuel cleaning additives can help clean the crud out if it's building up in the airways...

That's the question, how can diesel additives clean the EGR ?

This makes no sense at all. Diesel is not in touch with EGR valve, so no way it can clean it.

Agree with you - the diesel injectors are "after" this stage of the inlet manifold, so the question remains where does the carbon that builds up here come from, as the air filter should prevent dirt entering the system.

I have two speculative theories...

Firstly, I know that oil from my turbo bearlings in my A3 seeps out under pressure and gradually accumulates in the intercooler pipes. You can see the oil seeping from the bottom of the intercooler pipe seals and everyone says this is "normal" and nothing to worry about. Its never enough to drip but seeps past the plastic pipe seals and you can see an oil film around the outside of the joints.

Theory one is that as the turbo then spools up to high pressure, some of this oil film is then sucked through the intake pipework and when it hits the hot metalwork of the EGR valve, the oil will gradually build up and deposit a hardened film onto the internal surface of the valve.

Second option relates to the "dump valve". Every turbo has a dump valve that releases excess exhaust gas pressure if it builds up too much in the exhaust manifold, so that the turbo doesn't exceed its maximum speed.

That dump valve has to release the exhause pressure somewhere and in these emission wary times, it isn't going to be dumped straight into the atmosphere.

I'm wondering if these excess gases from the exhaust dump valve actually get channeled back into the inlet system. The exhaust gases would contain carbon and that would explain how carbon gets deposited into the inlet system.

[alfiejts]

Just found this - it explains it all....

http://www.egrvalve.co.uk/

Exhaust gas is recycled through to the intake system via the EGR valve to reduce engine emissions.

This page focusses on VW/Audi, but its going to be the same for many turbo-diesel engines, including the Yaris.

So the carbon is coming from the exhaust gas. That means that using a better fuel may well reduce the issue if it burns better and reduces the carbon/soot emitted through the exhaust....

On this site they actually sell options to "delete" the VW EGR valve altogether to stop the problems it causes on VW engines...

Symptoms and fixes are going to be engine specific, but at least this explains where the carbon is coming from...

EDIT: And here's a Toyota bulletin I've just found explaining all the theory of the EGR system from Toyota's perspective.... If you can't sleep at night, try reading this all the way through...

http://www.autoshop101.com/forms/h61.pdf

[Cyker]

I think dump valves usually dump to atmosphere (That's the WOOSH sound you hear when chavved up cars change gear ), but that won't affect us - Diesel engines don't really suffer from overboost (Petrol engines will get nasty pre-ignition effects with too much boost but diesels can be boosted as much as you like) and most D4D engines use variable vane turbos to vary the boost to prevent overboosting anyway.

The EGR is a well known source of carbon crap - we've seen so many posts about on this forum. The toyota blurb is for a petrol engine with an EGR, which I must admit I was surprised by; Didn't realize petrol engines had EGRs too - The *only* use of an EGR is to reduce NOx emissions, and almost all modern diesels have one because diesels burn really hot and for some reason that produces loads of NOx.

Petrol engines don't produce that much NOx, so fitting them with an EGR seems stupid (EGR produces more CO, particulates, and kills power!)

The first line of the egrvalve.co.uk blurb made me laugh - "The Exhaust gas re-circulation is incorporated in an attempt to reduce the level of nitrous oxide being emitted through the exhaust system." It's Nitrogen Oxide (NOx), not Nitrous Oxide (Laughing Gas)

If Nitrous Oxide was coming out my exhaust, I'd be bottling it and trying to sell it to janey and PaulT for their TSS runs

The biggest problem with disabling the EGR is the high risk of MOT failure, as the higher NOx levels will probably make the car fail the emissions test part (And I don't think you can gimp it by using e.g. V-Power like you can for the particulate emissions test )

I must admit I do wish the D4D had a regenerating 'afterburner' DPF like newer diesels as that should solve the soot problem, albeit at the cost of yet more fuel.

Supposedly new catalysts more advanced injectors will help cut down NOx and make the stupid EGR redundant in newer cars (I reckon the EGR probably costs us 5mpg!), but that won't help us much...

[chrsfrm]

Just wanted to say Thanks to Bob for the post on this. I did this clean up, car now as new. Invaluable advice. Thanks again. Great club. Chris.

[meanodeano]

thankyou so much my yaris was idleing eraticly on cold starts followed this tuturial and seems fine now, in the morning will real test but it was super clogged up, as stated in a previous post instead of a 12mm hole , it was about 3mm to 4mm hole,. who needs garages when you have great forums like this one

[Raistlin]

Its still cost me a bit though cos I managed to drop two sockets in the belly pan and can't get them out...

Why not try a magnet on a bit of string or wire ;)

[pete129]

Thanks , worked a treat for my 2004 Yaris D with 82k in the clock

Sent from my iPhone using Toyota OC

[trevt]

I just want to say a big thank you for this. My GF's yaris has been suffering this for a good few months now. I did the procedure yesterday and it cured it. Happy days :-)

Cheers,

Trev

[Madasafish]

Our 12 year old D4D Yaris failed its MOT test on Wednesday morning at Kwikfit (£30 online). Excessive ermissions: specifically smoke.

My wife drives it - slowly and averages 1 mile per journey. Her last diesel (a Peugeot 106) lasted 17 years under such a regime until crashed.. as it had no catalyst or EGR valve there was never a problem.

It would appear in her car's case, the catalyst had sooted up. (I cleaned the EGR valve 6 years ago.).

So I added a system cleaner to the tank and drove approx 30 miles - almost all at 3,000 rpm or more including 6 miles on dual carriageway...at 70mph in a mix of third and fourth gear.

On Thursday it was warmed up thoroughly and retested (FOC) and passed.

I cannot recall what test it was (opacity test?)... but the Before reading was 3.9 (a fail) and the After reading was 0.9 (a pass)..

Undoubtedly a badly sooted up catalyst...

[gazhat]

My 2003 1.4 D4D Yaris has been doing this for God knows how long and has been getting progressively worse, I was sent this link today and I've followed the instructions, mine was chockerblock full of cr@p so took it to bits, I've gave it a good clean, she seems to be better but my problem was more noticeable first thing on a morning when cold, I'll be able to tell when I start her up in the morning. 

I thought it was the solenoid sensors that cost £277 each so fingers crossed I'm good for a few more miles, although I'm on 140k now! Many Thanks! :)

[gazhat]

I can confirm my Yaris is now sorted thanks to this fix!

Performance wise, the difference is unbelievable, it's an absolute flying machine now, hits 90mph without any effort.

It starts up smooth as silk and purrs like happy kitten.

I put £20 in it the morning before I did the fix and I've done over 100 mile and I don't think the fuel gauge has moved a single bar! 

Thank You again Dustyhog, I only wish I'd found this post when it started doing it a couple of years ago, God only knows how much I would have saved in diesel :)

[peterpiper]

Yaris 04.   ERRATIC idle / rough idle / variable idle.

Thanks, I'd been searching for solutions to this for quite a while, before eventually stumbling on this post.  The page address uses spelling "eratic", so only come straight here if Goggle search is spelt  "eratic idle".

 

Rather than loostening the air-cooler:

ONE. Loosten jubilee clips on hose from the air cooler.

TWO Undo the 10mm bolts that hold the dipstick and the wiring loom to the casting.

THREE Undo all the 12mm bolts. You are dealing with aluminium, so undo all bolts a bit at a time to avoid distorting anything (same applies when re-fitting)

FOUR Take off the casting, pulling it down and forward to disconnect cooler hose. 

NOTE There are two airways from this casting into the engine, make sure both are clear. In my case the main air channel (about 45mm diameter) had 5mm of carbon build up,  only when scraping this out did the second chanel (about 12mm) become visible.

Question:  What's the second small air channel for?  I guess the largeer channel is air to the cylinders.