gtdi cold start problem?

**FLENG2008** · 28-01-2009,06:21 AM

hi the other day when i started the car from cold, the car seemed to rev-up a little bit on it's own (like i started the car with the accelerator slighlty pressed)
then this morning when i started it from cold it did the same reved-up on it own and the revs stayed pretty high (approx 1200rpm) until it reached around 90 then it dropped to the normal around 900rpm

has anyone experience any kinda problem like this before?

p.s the glow plug light seems to stay on for longer too, sometimes upto 5 secs, before it would only take about 2 secs

are these problems related, any suggestions appreciated

thanks

**Crasher** · 28-01-2009,10:21 AM

More than likely the coolant temperature sensor is faulty, get a code read done or take a chance and change the sensor. Sometimes a faulty sensor will not show up as a code if the reading given doesn’t seem unusual to the ECU, for example reading 20 degrees lower than it should so the only way to track that is to watch the reading in Measuring Blocks 08 and if you are paying someone to do that it is cheaper to just change the sensor.

**FLENG2008** · 28-01-2009,01:51 PM

thanks crasher , if it happens again i will ring you for a plug in

**FLENG2008** · 29-01-2009,08:54 PM

its been doing it again all day, even when its warm
when i start her up she revs upto 2000rpm then back down and settles about 1100rpm, sometimes it will drop back to 900rpm after a drive of about 30 or so

not sure if it still could be related to the temp sender?
and the glow plug light sometime takes ages to go off?
thanks

**Crasher** · 29-01-2009,10:01 PM

The temp sender tells the engines computer what the engine temperature is so it can respond in fuelling, idle control and glow plug strategy. If the signal from the sender is spiky and erratic, the computers response will be to ignore that sensor and go by a base map and by the inlet air temperature. You need a fault code read.