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ardandy

Weird Misfire Problem

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Ok this is what happens.

 

VR6

 

Engine cold, left overnight etc. I come out to use it and it takes a little longer to start and then when it does it last a few seconds before it cuts out.

 

If I keep my foot on the accelerator (say half way down) it revs a bit and then cuts out. The only way I can keep it from stalling is by constantly blipping the throttle (on, off, on, off etc). Even then it doesn't rev as much as it should.

 

This will carry on until it gets warm. When the car does get up to running temp it's fine, runs like a dream! Although it has done its cut out routine today when left idling for a while???

 

Now I'm hoping its just a spark plug problem as my engine has a habit of fouling up a couple of plugs but I've had someone say it could be my head gasket? Weeps water in when cold and is ok when it's warm as teh gasket expands? Dunno! It's lost about 1cm of water (looking at the header tank) in several months if that tells you anything.

 

I'm going to check the sparks when I get a socket set, any other ideas?

 

Oh, what size do I need for the sparks?

 

Cheers!

 

Andy

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Temperature sensor. The engine doesn't know it's cold so doesn't run the cold start enrichment.

Get the ECU error codes scanned.

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Aren't they a sub £20 item? If so I might just replace it regardless.

 

Yes, but you'll

a) lose a butt load of coolant

b) probably break the thermostat housing

c) get confused about which one you need to replace (there's three of 'em)

 

So it makes sense to check it out with VAG-COM first ...

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You can probably at least sanity check the sensors with a multi-meter first, but something like that you could be chasing your tail forever when all you have to do is ask the ECU and it'll tell you where it hurts ...

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I believe its the blue one that you need to check, the yellow one is for the fans and the black one i believe is for the emergency fan speed 3, but i may have heard wrong.

 

I thought mine was dodgy so whilst the car was idling cold i disconnected the temp sensor and bridged the connection with a paper clip/staple/wire/whatever to see what happened. I cant remember now which way round it is but if it doesnt do anything when you bridge it then it could be dodgy.

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Worth a shot but I can't get the thing to idle, cuts out after a second or three.

 

VAG-COM's probably the best bet. Just missed a GB on another forum too! :(

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Just (trying) to replace the blue temp sensor. I've got the plug off but I can't get the sensor out!

 

Is there something elde I need to do or do I just need to get a pair of pliers to it?

 

Cheers!

 

Andy

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Woohoo!

 

Replaced the temp sensor and it works a treat now!

 

We should have let you replace the head gasket for a laugh, then tell you afterwards that it's the temp sensor .. ;)

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Hi. My VR6 is idling OK but a bit hesitant until really warm. Thought I might change the infamous blue sensor too.

 

Can you tell me if it is easy to do. It's a plug in job on the back of the block right? Or should I get a VAG com done first?

 

Cheers

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I'd VAG-COM first as although mines better with the blue temp sensor, I've now found out that I need a new MAF (£220!!!!) and a new Lambda.

 

Temp sensor was a little fiddly (my aircon is in the way), but easy to do.

 

Unplug the sensor (its just below and to the right of the inlet manifol at the front), pull a clip up that holds it in place (a U shaped bit of metal) and then the sensor should pop out.

 

It's in a bank of 3 sensors. Try not to be too forceful as you don't want to break the sensor housing. Might also be easier if you remove your coolant res tank lid.

 

Just bear in mine that you'll lose loads of coolant so make sure you have some ready to top up when your done.

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