TDI coolant temperature sensor

[b1llyb0y]

Hi all,

I have a hard starting TDI when hot, can someone direct me to where the CTS is so that I can unplug it and see if it starts properly when hot?

Cheers!

[HiTorque]

There are two sensors in the cooling system - one controls fans and another one inside the thermostat. Also you will find a cooling temperature sender unit located in the radiator inlet. The sensors are not repairable. Also petrol and diesel engines have different control units employed for start.

[85turbo]

i too have a hard to start TDI when hot.
have been doing loads of research on this subject recently.

there seems to be a simple and cheap mod, that will "fix" the problem.
ill try to find a link to the info.....

Edit:

Link

ps, also note that if you remove the sensor completely, it will through a fault code, that will need to be cleared.

Jason.

[HiTorque]

i too have a hard to start TDI when hot.
have been doing loads of research on this subject recently.

there seems to be a simple and cheap mod, that will "fix" the problem.
ill try to find a link to the info.....

Edit:

Link

ps, also note that if you remove the sensor completely, it will through a fault code, that will need to be cleared.

Jason.

That link isn't good for mkV TDI.
What I understood a signal to ECU about engine temperature comes from cooling system sensor, and when engine is hot a glow plug heater is not activated. I noticed when engine is hot it takes perhaps 2 sec longer to start, but if it takes longer than 4-5 sec I would take it for diagnostics.

[b1llyb0y]

When cold mine starts immediately after the glow plug light has switched off (first or second crank), but when hot it cranks about 4 - 5 times before it fires up which is probably around 2 - 3 seconds.

I have it booked in with Volkspower on Sat. 6th June, where I will get my camshaft timing checked on vag-com and this hot start issue looked at .. perhaps its only the camshaft timing that needs an adjustment?

That link isn't good for mkV TDI.
What I understood a signal to ECU about engine temperature comes from cooling system sensor, and when engine is hot a glow plug heater is not activated. I noticed when engine is hot it takes perhaps 2 sec longer to start, but if it takes longer than 4-5 sec I would take it for diagnostics.

[Greg Roles]

I'd doubt your timing is out, would make for a very noticable difference in power if the timing was out one tooth. Probably put valves into your pistons as well given the tiny compression space they have to open into.

Odd problem, as a diesel should be easier to start hot, as it obviously relies on compression heat to make the bang. Hmmm, odd...

[neil]

Is it hard to start immediately after stopping.
Eg. you stop the engine and try to start straight away or
Has it been hard to start after its been stopped for say 15 minutes.

[85turbo]

n my case, it's always been after a 10 or 15 minute stop.
It's only happened 2 times so far.

When it does, the engine will crank and crank for like 10 seconds
Before finally starting. It's not laboured cranking either.
It's cranking over as normal. Just no start.

When it's cold, it starts almost immediatly.

Jason.

[b1llyb0y]

I am told over at TDICLUB that the camshaft timing can be changed by simply loosening a bolt and adjusting back/forth and its a known problem that the timing can change because it becomes a little loose (not enough to cause piston to valve contact)

The reason I am thinking that it may be camshaft timing is when I kick it in the guts it leaves a smoke trail that is embarrassing, yet somehow very satisfying .. hehe (which has been mentioned on TDICLUB to be camshaft timing out).

I'd doubt your timing is out, would make for a very noticable difference in power if the timing was out one tooth. Probably put valves into your pistons as well given the tiny compression space they have to open into.

Odd problem, as a diesel should be easier to start hot, as it obviously relies on compression heat to make the bang. Hmmm, odd...

[b1llyb0y]

It is immediately hard to start after stoping (when engine is at operating temp)

It will continue to stay hard to start until the temperate drops maybe 15 - 20c from normal, then it will start immediately again.

Is it hard to start immediately after stopping.
Eg. you stop the engine and try to start straight away or
Has it been hard to start after its been stopped for say 15 minutes.

[b1llyb0y]

It turns out after taking my car to Volkspower that it seems to be the starter motor which is a known issue, but I wont be replacing it soon at over $900 for it.

Hi all,

I have a hard starting TDI when hot, can someone direct me to where the CTS is so that I can unplug it and see if it starts properly when hot?

Cheers!