Any Diesel D-4d Experts Out There ?

[Johnaa]

Mk 1 Yaris - 1.4 D-4D engine - low mileage (20,000miles). I have developed a problem with slow running when the engine is first started from cold. For about the first minute the engine runs smoothly. It then starts to run with what can only be described as a blub,blub,blub rhythm. It sounds as if the engine fires four times then misses four times then fires four times and so on. Increasing the revs stops it but it returns when when dropped back to idle speed. Once the engine warms up this strange rhythm disappears (after a couple of minutes) although as time goes on it is taking longer to disappear. Once it is warm, the engine runs absolutely perfectly at all speeds. Fuel consumption is very good ( between 55 and 65 MPG depending on conditions) as it has always been.

I have tried the following but with no improvement:

Checked for water in fuel filter - none found.

Tried premium diesel fuel - no difference.

Tried BD44 injector/fuel system cleaner additive - no improvement.

The fault appears to be engine temperature related so I have the feeling it is to do with some kind of sensor malfunction or blockage. I have wondered about air flter change but cannot see how this would relate to temperature.

I have noticed that the small vacuum unit at the top front of the engine goes in and out with this rythmic running but assume this is an effect rather than a cause.

Has anybody experienced anything like this? - or have any constructive ideas? I am reluctant to book the car in as I think the problem could be difficult to reproduce as it only happens for a short while when engine is cold. Thanks.

[GIDDLEPIN]

Hi John and welcome to the club

My diesel experience relates to the heavy haulage industry but it could be a number of things from a sensor to the injector pump, as you haven't mentioned that the CEL is showing and it runs ok once warm it doesn't sound to be overly serious more of an annoyance.

If there is no CEL the I would imagine a diagnostic check won't be a lot of help either.

Surging can be caused by some of the things you mentioned, dirty fuel, blocked fuel or air filter, water in fuel or even a faulty injector pump, I have even had it caused by faulty none return valves that let fuel back siphon to the tank or leaking fuel pipes that allow air into the system.

So I'm afraid it looks like it will be either process of elimination or put yourself in the hands of a workshop.

Les

[Johnaa]

Hi John and welcome to the club

My diesel experience relates to the heavy haulage industry but it could be a number of things from a sensor to the injector pump, as you haven't mentioned that the CEL is showing and it runs ok once warm it doesn't sound to be overly serious more of an annoyance.

If there is no CEL the I would imagine a diagnostic check won't be a lot of help either.

Surging can be caused by some of the things you mentioned, dirty fuel, blocked fuel or air filter, water in fuel or even a faulty injector pump, I have even had it caused by faulty none return valves that let fuel back siphon to the tank or leaking fuel pipes that allow air into the system.

So I'm afraid it looks like it will be either process of elimination or put yourself in the hands of a workshop.

Les

Hi Les, Thanks for that. You are right that it is an annoyance although I would like to clear it up as I am afraid it is the start of something that could get more serious or even cause a breakdown. I am very surprised that I have had no other replies as I am sure there are Toyota technician members out there who have come across this. Can you suggest how I might post again and get more replies. Regarding putting it into a workshop, my fear is that as it is not a long lasting problem and does not show up any error codes they might do a lot of expensive trial and error procedures. Regards John

[QAS]

Hi John and welcome to the club

My diesel experience relates to the heavy haulage industry but it could be a number of things from a sensor to the injector pump, as you haven't mentioned that the CEL is showing and it runs ok once warm it doesn't sound to be overly serious more of an annoyance.

If there is no CEL the I would imagine a diagnostic check won't be a lot of help either.

Surging can be caused by some of the things you mentioned, dirty fuel, blocked fuel or air filter, water in fuel or even a faulty injector pump, I have even had it caused by faulty none return valves that let fuel back siphon to the tank or leaking fuel pipes that allow air into the system.

So I'm afraid it looks like it will be either process of elimination or put yourself in the hands of a workshop.

Les

Hi Les, Thanks for that. You are right that it is an annoyance although I would like to clear it up as I am afraid it is the start of something that could get more serious or even cause a breakdown. I am very surprised that I have had no other replies as I am sure there are Toyota technician members out there who have come across this. Can you suggest how I might post again and get more replies. Regarding putting it into a workshop, my fear is that as it is not a long lasting problem and does not show up any error codes they might do a lot of expensive trial and error procedures. Regards John

I have exactly the same probelm, engine starts fine but after a minutes or so it starts going blurb, blurb, blurb. Once the engine is warm problem dissapear. This has been happening since last month. I would like to know if anyone has a solution to this problem. I took it toyota for a check up, unfortunately this only lasts for about 5 minutes and by the time i get to local toyota dealer the problem is gone.

So if any Toyota techies have any idea then please forward to us.

Thank you

[Benno_uk]

Yaris D4D engines are prone to the EGR valve cokeing up. And there is also a vacum controled air butterfly in the inlet system that also cokes up. I would remove both these item and clean the crap out. If either of these are sticking, it will cause the symptoms that you describe.

[QAS]

Yaris D4D engines are prone to the EGR valve cokeing up. And there is also a vacum controled air butterfly in the inlet system that also cokes up. I would remove both these item and clean the crap out. If either of these are sticking, it will cause the symptoms that you describe.

Thanks for the reply Benno, very much appreciate it. Do you have any pictures of these items, and are they easily accessible and removable.

Please let us know.

Kind regards

QAS