Yaris 2005 D4D idle problem

[JaiCongiu]

Hi, please help. It's hard to explain but my engine, while at idle, runs up and down as if someone is pressing the accelerator momentarily on and off over and over again. If I unplug the vacuum control (If that's what it is) it runs smoothly again. Any ideas? I've tried replacing the vacuum controller that it is connected to. Maybe I need to replace both but I'd rather see if anyone knows what's up. 

[flash22]

have you changed the valve? Have you also changed the green/white filter?

do you have a vacuum on the pipe feeding the valve?

also, the bottom of the intake hose looks very wet with oil

[flash22]

Try disconnecting/blocking or clamping the vacuum pipe to the EGR control valve that valve may be leaking past

the pipe arrowed

 

 

[Cyker]

Aha! I have had this exact issue on both my Mk D4Ds, and it seems very common on cars that don't see a lot of long hard runs.

The symptoms are a fluctuating idle, and if you look in the engine while it's happening, the little metal 'foot' actuated by the metal flying-saucer-looking thing will keep moving back and forth instead of staying in one place.

Looking at the front of the engine, there is a throttle-body on the left-side of the intercooler connected to the big turbo hose - If you take it off and look inside, there should be a passage that goes to the EGR through a passage in the engine lock, but it will be blocked with soot and may even look like there is no such passage because it's covered so perfectly by soot.

If you clean the bejeezus out of the inside of it with brake cleaner, and dissolve all the crusted soot, it will reveal a tiny hole about the size of a 5p piece.

Once that passage is nice and clear,put everything back together and it should fix the problem. It may be worth spraying some brake cleaner down the passage too, but it may trigger some nasty detonation misfires when the engine starts as there will be 'fuel' in the engine when there shouldn't be.

 

[flash22]

to the left is the throttle body, and the EGR is on the right with the egr cooler linking them, it looks like an mk1 (P10) 1ndtv, it has a mechanical egr and TB, which are all vacuum-controlled the EGR control valve is a purge and seal type system with a vent on the valve whats fed off the same vacuum line

the mk2 ones are electronic with smaller EGR cooler pipes as you describe

[JaiCongiu]

21 hours ago, Cyker said:

Aha! I have had this exact issue on both my Mk D4Ds, and it seems very common on cars that don't see a lot of long hard runs.

The symptoms are a fluctuating idle, and if you look in the engine while it's happening, the little metal 'foot' actuated by the metal flying-saucer-looking thing will keep moving back and forth instead of staying in one place.

Looking at the front of the engine, there is a throttle-body on the left-side of the intercooler connected to the big turbo hose - If you take it off and look inside, there should be a passage that goes to the EGR through a passage in the engine lock, but it will be blocked with soot and may even look like there is no such passage because it's covered so perfectly by soot.

If you clean the bejeezus out of the inside of it with brake cleaner, and dissolve all the crusted soot, it will reveal a tiny hole about the size of a 5p piece.

Once that passage is nice and clear,put everything back together and it should fix the problem. It may be worth spraying some brake cleaner down the passage too, but it may trigger some nasty detonation misfires when the engine starts as there will be 'fuel' in the engine when there shouldn't be.

 

Hi, thanks so much for this advice. It was unbelievably clogged and I would never have known. It's now clean and, though I've only run the engine for a few minutes, it's running smoothly. I'm extremely happy with this. Thank you so much 

[Cyker]

Glad to help!  

I wasted a load of money getting garages to look at it to try and figure out the uneven idle so glad I could give someone a shortcut! They all thought it was the EGR and cleaned it out, which helped a bit, but didn't fix it completely and the general consensus was that I needed a new one.

It was only my travelling mechanic mate, after hearing my tales of woe, who thought to look at that throttle body. When he took it off he didn't see anything obviously wrong, aside from the soot, but it was a nice even coating so nothing obviously untoward. It was only when he noticed there was a passage which seemed to go nowhere, and decided to clean out the soot just to be sure, that we discovered that there was indeed a hole, blocked and perfectly smoothed over by soot!  

I will recommend throwing in a tankful of Shell V-Power diesel and taking it on a good hoon on some fun roads now and then, as that seemed to help stave off the problem by getting everything hot and putting some strong air flow through it to help burn off some of the soot. I only had to get that throttle body cleaned once for each of my Mk1 D4Ds shortly after buying them, and I reckon giving it a good run now and then helped keep it clear after that.

 

I'm glad you got it fixed and hope the car gives you a long run! They're rarer than hens teeth now so look after it!! I must admit, although the Mk4 hybrid is a good car, I still miss my Mk1 D4Ds a bit! Would probably still have it if not for our idiot Mayor KHAAAAAN!

[JaiCongiu]

My yaris has only done 80k miles so she should run for a long while yet. That would also explain the short journey issue with clogging up the pipes as the car is 20 years old now. I had an old lady park next to me a while back and she was excited to tell me how much she loved her yaris and had it from new, telling me she's never had any issues with it. 

[Cyker]

It's a very good car and IMHO one of the best cars Toyota ever made. Very comfy, bullet-proof reliability, cheap to run, has solid torque through the whole rev range thanks to the variable geometry turbo (Seriously who puts a variable geometry turbo in a small mass-produced diesel car?? The only other car I know of that has such a thing is a Porsche!!   ), so many places to put stuff, and the diesel ones were made in japan so even more reliable than the petrol ones aside from the T-Sport! The really broke the mold when they made that car; I had to wait 20 years for someone to make a car that had better real-world fuel economy!  

[Billzcmy871]

Can someone post the picture of Diesel Throttle body for d4d 2006 and its exact location in the engine. if someone has uploaded a video of detaching it for the engine for the purpose of cleaning . It will be highly appreciated