Does the Coolant temperature sensor control the SAI?

[Mannyg60]

Hi
I'm starting to have problems first thing in the morning with my cupra 1.8,t.

It struggles to start and won't go straight away like it used to. It bogs down as soon as I set off.
I've noticed that the SAI doesn't kick in either.

Is it connected to the coolant temp sensor as could be faulty.

Once it gets going after about a minute it's perfect, pulls really well and doesn't hesitate.
Starts up fine when it's warm too.

Thanks in advance

 

[mty12345]

Yes mate, it's activated by the CTS showing under a certain temp (30C I think) at start up. Mine will misfire and hesitate while the SAI is running too, although mine has no trouble starting. I think the root cause is either the combi valve, or possibly ( and maybe more likely) the varible valve timing not adjusting itself properly, as the only time these engines use the VVT is while the SAI is running.

Basicly you have a few options:

1. Let it idle until SAI turns off on the first cold start of the day (my preferred option, seeing as the car runs perfectly after that first 60 secs)

2. Junk the SAI and get the fault code/light removed from the ECU by a specialist (i'm guessing they flash the cold start files from the LCR, as it doesn't have SAI, although i'm far from sure)

3. Spend time and money trying to work out exactly whats going on and replacing whatever part is faulty.

 

[Mannyg60]

I'm going to change the coolant temp sensor and see if that makes any difference. On a start up in the morning the SAI doesn't come on, it used to come on without fail. Cheers for the reply .

 

[mty12345]

I'm going to change the coolant temp sensor and see if that makes any difference. On a start up in the morning the SAI doesn't come on, it used to come on without fail. Cheers for the reply .

Sorry buddy, I misread what you'd written lol.

Yeah, if it's hard to start and the SAI doesn't fire up, then i'd say 99% certain that the CTS is constantly showing a hot engine. That would explain both issues as the air/fuel mixture will be too weak for a cold engine to start and run correctly.

 

[Rich.T]

Whats an SAI?

 

[Mannyg60]

Whats an SAI?

Secondary air intake aka the hoover that comes on to warm up the car

 

[mty12345]

Whats an SAI?

Lol, yh think yourself lucky the LCR doesn't have it fitted mate. It injects extra air into the exhaust manifold to warm up the cat quicker.

As manny said they sound like a hoover, although if you drill out the rivets and either redo them or use nuts and bolts instead, then that does quieten them down a lot. The top cover coming loose over time is what makes them sound so bad.