850 T5 Idle Control Valve
Discussion
Hello, me again.
Ever since buying the car 18 months ago I've had the revs rise when changing up through the gears on part throttle.
Read up and researched it and it is the MAF thing sticking it appears.
Took hoses off yesterday and it needed cleaning.
However, after doing this, went for a spin and car much better. Also noticed a slight crackle/pop on over run when coasting, which suggests to me something has improved. Car goes like stink, not jerking when coming off the power. There was a slight delay and a sensation of the car driving itself almost for a second or two before doing the clean.
Great I thought. However, I realised I had not plugged in the electrical connection to the idle control valve. When I did car drove crappy again.
Started it this morning disconnected and idled really slow, but fine when warmed up.
Will I harm the engine in any way with it disconnected? It drives lovely. There must be catch?
More fuel? Or does something get knackered?
Also, prior to this the engine check light had come on. This was after a long journey at constant speeds, which seems to set it off sometimes. Car exhaust smells rich or weak, but smells stronger in a sweet smelling way.
Thought it might be a leaky exhaust, so had it fixed, but light still on. I've guessed it doesn't like sitting at same revs, something gets 'stuck' but after a few days it works free and goes out, resulting in car not smelling anymore either.
So cleaned out the above MAF, and light still on.
However, I now understand if I have the Idle CV unplugged the light will be on anyway.
My conclusion is the Idle control valve is knackered, hence the jumpy running when it is connected and light on, or if unplugged light will be on anyway.
Am I right? Cheers in advance!
Ever since buying the car 18 months ago I've had the revs rise when changing up through the gears on part throttle.
Read up and researched it and it is the MAF thing sticking it appears.
Took hoses off yesterday and it needed cleaning.
However, after doing this, went for a spin and car much better. Also noticed a slight crackle/pop on over run when coasting, which suggests to me something has improved. Car goes like stink, not jerking when coming off the power. There was a slight delay and a sensation of the car driving itself almost for a second or two before doing the clean.
Great I thought. However, I realised I had not plugged in the electrical connection to the idle control valve. When I did car drove crappy again.
Started it this morning disconnected and idled really slow, but fine when warmed up.
Will I harm the engine in any way with it disconnected? It drives lovely. There must be catch?
More fuel? Or does something get knackered?
Also, prior to this the engine check light had come on. This was after a long journey at constant speeds, which seems to set it off sometimes. Car exhaust smells rich or weak, but smells stronger in a sweet smelling way.
Thought it might be a leaky exhaust, so had it fixed, but light still on. I've guessed it doesn't like sitting at same revs, something gets 'stuck' but after a few days it works free and goes out, resulting in car not smelling anymore either.
So cleaned out the above MAF, and light still on.
However, I now understand if I have the Idle CV unplugged the light will be on anyway.
My conclusion is the Idle control valve is knackered, hence the jumpy running when it is connected and light on, or if unplugged light will be on anyway.
Am I right? Cheers in advance!
morgrp said:
I have a spare one kicking about somewhere - if I can find it you can have it - that's if I haven't chucked it of course - I'll have a look this week when a get a chance
What a nice man!It runs lovely, apart from when cold and almost stalls. Rather have it a bit stally when cold instead of jerky all the time when warmed up, but the Emissions light is on with it disconnected.
Cars eh?
That's normal behaviour for one with out an idle control valve - the one on my merc cosworth started playing up (very similar Bosch part) I bypassed it for a while - just had no idle when cold but was fine once warmed up -
Might be worth investing in a cheap obd II reader on amazon to put the light out - alternatively sometimes disconnecting the battery for around 24hours will clear the ecu codes and put the light out
Might be worth investing in a cheap obd II reader on amazon to put the light out - alternatively sometimes disconnecting the battery for around 24hours will clear the ecu codes and put the light out
Well I've took the ICV off today and cleaned it out with brake cleaner spray.
Got it loosened up and moves as it should inside.
Put it back on and car still a bit jerky, though better.
Disconnect it again via electrical connection and runs lovely.
My thoughts are that either it is knackered electrically, though as mechanism free inside it appears better now, instead of stuck in one position.
Or the ICV is not getting an electrical signal to operate.
However, the car does not have that rich smell anymore, though emissions light still on.
It has come on before and gone off again after a week maybe, but I put that down to motorway running/using normal unleaded instead of super unleaded.
I'll park it now, with it all connected up, and disconnect battery.
Can't really do much else.
Thanks for advice and any input always welcome.
Got it loosened up and moves as it should inside.
Put it back on and car still a bit jerky, though better.
Disconnect it again via electrical connection and runs lovely.
My thoughts are that either it is knackered electrically, though as mechanism free inside it appears better now, instead of stuck in one position.
Or the ICV is not getting an electrical signal to operate.
However, the car does not have that rich smell anymore, though emissions light still on.
It has come on before and gone off again after a week maybe, but I put that down to motorway running/using normal unleaded instead of super unleaded.
I'll park it now, with it all connected up, and disconnect battery.
Can't really do much else.
Thanks for advice and any input always welcome.
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