Any suggestions please?

[SCVRS]

Anyone have any suggestions please. Mk1 VRS is a nightmare when cold. Starts fine then judders and splutters even after the sai has done it's thing. When warmed up it seems down on power and turbo seems to dump early and too quick when I lift off. Changed MAF and cleared fault codes 17705 p1297, 17546 p1138 and 177548 p1140. The DV seems fine too. Last night I disconnected the MAF and drove it, the issue was still there. This morning I reconnected the MAF, but didnt clear fault codes and it started then spluttered and died! Disconnected the MAF again and it stayed running! Anyone have any ideas please? Fault codes returned after I replaced the MAF, I'm aware I could have fitted a faulty MAF too, but any other suggestions please. Vag com bank 32 reading is -5.4%

[YellowCar]

Coolant temp sensor?

[SCVRS]

Thanks for the suggestion, I've had coolant temp sensor go on my previous vrs and that simply showed some weird coolant reading on the display. Would it more likely be the air intake temperature sensor? The one on the throttle body?

[KenONeill]

CTS can give duff values to the EMS and good ons to the gauge.

[YellowCar]

You can try cleaning the air temp sensor, carb cleaner is fine just don't damage the element. It still sounds like cts to me, as Ken says it's not just about what the display says, and it can cause some weird running issues. It's not uncommon and a cheap thing to try. Did you replace your duff one with a gen one?

[KenONeill]

If we're thinking air temp sensor, cross-check the trip computer temperature against the Climatronic (if fitted); they use 2 separate sensors and should be the same or 0.5C deg different (the trip reads to half degrees, the Climate only to full ones).

[eugmul]

If we're thinking air temp sensor, cross-check the trip computer temperature against the Climatronic (if fitted); they use 2 separate sensors and should be the same or 0.5C deg different (the trip reads to half degrees, the Climate only to full ones).

If they read close does this mean it's not the air temp sensor?

Mine has similar issues and has had the coolant sensor changed.

[KenONeill]

If they read close does this mean it's not the air temp sensor?

Mine has similar issues and has had the coolant sensor changed.

It means it's unlikely to be the air temp sensor.

[eugmul]

Cheers, I'll have to investigate a bit further then

[eugmul]

Cheers, I'll have to investigate a bit further then

[kentphil1]

The last 2 codes you list there suggest a lean condition at the oxygen sensor.

 

If you are sure the CTS is functioning correctly, then I would check under the Y pipe by the dump valve, especially underneath the the y part of the pipe as they rot there.

 

Also, is  the PCV valve in good nick and not gummed up?.

[Rspowerplus]

Air temperature sensor

I've had same issue, cleaned mine and now no issues. Will buy new when I have the spare cash