Thread: TD5, Noise when cold.

Hey guys,

Thanks for the replies.

I did some googling after I made the post last night and I think the best way to descibe the noise is a diesel knock.

It's not progressive at all. It's an immediate change of engine noise from the usual smooth TD5 sound to a 1HZ toyota with 400,000km on it. I can stop it emmediatly by backing off the accelerator and then induce it again by putting the accelerator down. It starts somewhere between 1200 - 1500rpm with load as it happens while I am driving.

As it's completely gone within about 60sec - 2 minutes of driving or it wont do it if I let it idle for 4 - 5 minutes.

I have recently purchased a new tune from TD5 inside so I am considering the injection timing could be too far advanced but I dont know if that is a parameter that can be changed with the mapping. I am suspecting if this is what it is it needs to be retarded a little for cold start up but again I dont know if this is a changable parameter. I am on night shift and dont have access to my personal email at work so I'm waiting until next week to email Jose (TD5inside).

My second thought and most concerning is that maybe oil is taking a while to reach some part of the motor. I dont have much idea on oil flow around the TD5 though.

And then there is just the simple things like crank angle sensor causing the advancment of the injection timing but I have no codes in Nanocom.

Thanks for any info guys.

Thanks for having a go "Redback" but a the TD5 has a Viscous fan. I'm no expert on these but I know the TD5 viscous fan is completely mechanical. I have never seen one apart but they are some sort of fluid (oil) coupling that has a bi-metal spring that causes the fan to be driven when the hub gets heated from hot air passing through from the radiator. I am aware that some of these viscous fans are driven when they are cold. I think the cold driving has something to do with the oil settling but once it spins up and distributes with the centrufigal force and then works as per normal. Basically the viscous fan has nothing to do with the injector harness which is an electrical item.

I haven't ruled out the injector harness though as I have had problems with mine in the past. I have never found any oil in the harness but I had a bad connection on one of the injectors. Unplugging and replugging fixed it initially but I have since given each connector a little bend to make sure the connection is good. I do intend to order a new one but I want to combine the freight with a couple of other parts like the radiator return line which is very brittle in my Disco. Just waiting to get the funds together but I keep spending it on other things breaking. I just dont know how the harness could cause the noise. When it's not making connection the engine runs very rough as one cylinder is not getting fuel to fire. It is possible though that there is something not making connection and once it gets a little heat it expands and makes connection. It wouldn't explain how the noise comes with engine load/rpm though.

Happy Days.

I may have the wrong end of the stick, but while cold, diesels will pink when cold, due to combustion taking slighty longer without heat in the engine. If I have mis understood the noise, just a thought, check the harmonic balancer on the crank pulley. When this starts to go, there will be movement as the two metal parts knock together.

Cheers
Nick

TD5 5 cylinder with only 4 glow plugs!
Its just No5 has the delayed combustion.

Regards

Its normal. Ignore it.. Engine starts as normal when cold? Possible slight rough running when very cold as only 4 glow plugs... Then settles down to a normal idle. All good so far...? You trundle down your drive.. No odd noise yet? You pull out onto the road and as you accelerate, the engine note goes from a smooth td5 sound to an instant cackle (still an even sound but sounds like the timing has been advanced). It does it again in second and poss 3rd on really cold days, but then you don't hear it again until the following day on another cold start and departure? My 99 130 Td5 used to do it every morning except on the summer days. The new Hilux's do it too.. I am pretty sure its the ECU advancing the point at when injection commences to help with initial engine warming. Tombie might be able to shed more light on this as he's a Td5 guru.

Originally Posted by Sitec

Its normal. Ignore it.. Engine starts as normal when cold? Possible slight rough running when very cold as only 4 glow plugs... Then settles down to a normal idle. All good so far...? You trundle down your drive.. No odd noise yet? You pull out onto the road and as you accelerate, the engine note goes from a smooth td5 sound to an instant cackle (still an even sound but sounds like the timing has been advanced). It does it again in second and poss 3rd on really cold days, but then you don't hear it again until the following day on another cold start and departure? My 99 130 Td5 used to do it every morning except on the summer days. The new Hilux's do it too.. I am pretty sure its the ECU advancing the point at when injection commences to help with initial engine warming. Tombie might be able to shed more light on this as he's a Td5 guru.

What you've explained is exactly what it does. I hadn't noticed it before and now it hasn't done it for the last couple of days.

I don't know about the glow plug thing. I thought they only help with initial starting. As far as I know, they don't continue to have effect once the engine starts.

Thanks for the replies guys.

I'm thinking it's a timing thing and not mechanical at the moment.

Happy Days.

Mine had this noise all the time on light throttle once EGR was disabled but only when warming-up originally. I used it to advantage in enclosed car-parks to alert pedestrians.

EGR removal will cause the diesel rattle. On mine most light to medium throttle openings that would normally trigger EGR operation had rattle to some extent.

EGR apparently delays the point of self-ignition, so injector timing has to be advanced to compensate. If you remove EGR the injection timing is too far advanced and you get rattle under some circumstances. That is the downside of EGR removal.

Not sure that this is Joel's issue, however.

Yes, the injector advance can be adjusting in the map files. There are also a lot of maps which provide corrections and adjustments for various conditions.

One of the intentions of diesel EGR is to delay combustion to reduce the noise on light throttle. The noise didn't bother me.

Edit: LR didn't advance the timing to compensate for when EGR was operating, rather the timing got delayed and throttle response sufferred.