Subaru Impreza Forum

themacka · 06 Jan 2006, 05:33 PM

Got a RB5 that has just started to drop the revs right down when it is idling like it's going to cut out but then kicks back in.
Sometimes after driving and you stop quick the revs drop and it cuts out.

Any ideas please??

BIG GRINDER! · 06 Jan 2006, 07:03 PM

Quote:

Originally Posted by themacka

Got a RB5 that has just started to drop the revs right down when it is idling like it's going to cut out but then kicks back in.
Sometimes after driving and you stop quick the revs drop and it cuts out.

Any ideas please??

Perhaps the cars Ecu has been reset. If the battery has been disconnected for a long time it will take 200 miles for the ECU to sort its self out.

My car cut out once after a reset at low idel speed.
Hope this helps and Welcome Kev

themacka · 06 Jan 2006, 07:25 PM

Thanks Kev!
I don't think the ECU has been reset. It fine when it is cold, but after it's warmed up it idles normally, then drops as if it is going to stall but then kicks in again. I am gonna have to take it in to be checked I suppose.

N_Collins · 06 Jan 2006, 07:59 PM

Sounds like the idle control valve. Do a code read on the ecu and then reset it and see what happens.

ANDY T · 06 Jan 2006, 08:53 PM

i had this problem with my p1 it woz the idle control valve on mine hope u get it sorted mate

BIG GRINDER! · 06 Jan 2006, 10:20 PM

Hi I recon You let the Ecu Sort things out.

Then get back to.org

Enjoy Kev.

bob · 06 Jan 2006, 11:07 PM

Sounds like a MAF problem. First sign of a MAF problem is unstable tickover. Don't want to worry you but don't boot it untill you have had the MAF cheched out.
A quick test of the Maf is with car warm let it tickover and unplug the MAF the engine should cut out. If the car still ticks over be it a bit unsteady the MAF is on its was out.

brumbrum · 07 Jan 2006, 01:07 PM

Quote:

Originally Posted by bob

Sounds like a MAF problem. First sign of a MAF problem is unstable tickover. Don't want to worry you but don't boot it untill you have had the MAF cheched out.
A quick test of the Maf is with car warm let it tickover and unplug the MAF the engine should cut out. If the car still ticks over be it a bit unsteady the MAF is on its was out.

from my experience i agree with bob. had exact same prob some months ago. had the MAF changed under warranty and has been fine since. idling low and cut out twice at lights.

ANDY T · 07 Jan 2006, 05:39 PM

as bob says it could be the maf thats what wos wrong with mine to start with i bought a new maf and the revs were still dropping every no and then cleaning the control valve finally sorted it

themacka · 08 Jan 2006, 11:49 AM

Thanks for all the advice guys!

minny · 09 Jan 2006, 05:14 PM

as every one has mentioned already, its either the idle speed control valve or maf sensor... would try cleaning out the valve first then change maf sensor next if it doesn't help... that's what happened to mine... hope that helps... use plugs below dash to read codes in case something is logged without triggering the engine check light

Nelson · 10 Jan 2006, 10:46 PM

May I ask what dump valve you are running with ?? cos apart from the previous suggestions a VTA dump valve can do exactly what you are describing.

06 Jan 2006, 05:33 PM	#1 (permalink)
themacka Fresh Scooby Join Date: Jan 2006 Posts: 3	Revs dropping on idle!! Got a RB5 that has just started to drop the revs right down when it is idling like it's going to cut out but then kicks back in. Sometimes after driving and you stop quick the revs drop and it cuts out. Any ideas please?? Last edited by themacka; 06 Jan 2006 at 05:37 PM.
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06 Jan 2006, 07:25 PM	#3 (permalink)
themacka Fresh Scooby Join Date: Jan 2006 Posts: 3	Thanks Kev! I don't think the ECU has been reset. It fine when it is cold, but after it's warmed up it idles normally, then drops as if it is going to stall but then kicks in again. I am gonna have to take it in to be checked I suppose.
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06 Jan 2006, 07:59 PM	#4 (permalink)
N_Collins Cool Scooby Join Date: Apr 2004 Location: Cornwall Posts: 254	Sounds like the idle control valve. Do a code read on the ecu and then reset it and see what happens.
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06 Jan 2006, 08:53 PM	#5 (permalink)
ANDY T Fresh Scooby Join Date: Jan 2005 Location: s.yorks Posts: 34	i had this problem with my p1 it woz the idle control valve on mine hope u get it sorted mate
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06 Jan 2006, 10:20 PM	#6 (permalink)
BIG GRINDER! Dedicated Scooby Join Date: Dec 2004 Location: Lancashire Posts: 2,458	Hi I recon You let the Ecu Sort things out. Then get back to.org Enjoy Kev.
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06 Jan 2006, 11:07 PM	#7 (permalink)
bob Senior Scooby Join Date: Jul 2004 Location: Bristol UK Posts: 1,547	Sounds like a MAF problem. First sign of a MAF problem is unstable tickover. Don't want to worry you but don't boot it untill you have had the MAF cheched out. A quick test of the Maf is with car warm let it tickover and unplug the MAF the engine should cut out. If the car still ticks over be it a bit unsteady the MAF is on its was out.
Offline

07 Jan 2006, 05:39 PM	#9 (permalink)
ANDY T Fresh Scooby Join Date: Jan 2005 Location: s.yorks Posts: 34	as bob says it could be the maf thats what wos wrong with mine to start with i bought a new maf and the revs were still dropping every no and then cleaning the control valve finally sorted it
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08 Jan 2006, 11:49 AM	#10 (permalink)
themacka Fresh Scooby Join Date: Jan 2006 Posts: 3	Thanks for all the advice guys!
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09 Jan 2006, 05:14 PM	#11 (permalink)
minny Fresh Scooby Join Date: Nov 2005 Location: Belfast Posts: 44	as every one has mentioned already, its either the idle speed control valve or maf sensor... would try cleaning out the valve first then change maf sensor next if it doesn't help... that's what happened to mine... hope that helps... use plugs below dash to read codes in case something is logged without triggering the engine check light
Offline

10 Jan 2006, 10:46 PM	#12 (permalink)
Nelson Dedicated Scooby Join Date: Apr 2004 Location: South West Posts: 2,659	May I ask what dump valve you are running with ?? cos apart from the previous suggestions a VTA dump valve can do exactly what you are describing.
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