MY99 Sti cutting out when coming to a stop?
21 October 2010, 12:29 PM
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MY99 Sti cutting out when coming to a stop?
Hey,
Didn't really want to start my first post with something negative.... but here goes.
Just bought a 1999 Sti and I'm having a problem where if I come upto a junction or set a traffic lights and drop the clutch, ready to stop, the car will try and stall and occasionally does stall.
Like I say though, doesn't do it all the time but its obvious something isn't right. When the car is idling at a stand still it doesn't fluctuate and holds a steady 850rpm.
A friend told me it could be the dump valve causing the problem (Turbo XS) but then someone else said it could be the maf...
Can anyone help me?! lol.
Many thanks
Didn't really want to start my first post with something negative.... but here goes.
Just bought a 1999 Sti and I'm having a problem where if I come upto a junction or set a traffic lights and drop the clutch, ready to stop, the car will try and stall and occasionally does stall.
Like I say though, doesn't do it all the time but its obvious something isn't right. When the car is idling at a stand still it doesn't fluctuate and holds a steady 850rpm.
A friend told me it could be the dump valve causing the problem (Turbo XS) but then someone else said it could be the maf...
Can anyone help me?! lol.
Many thanks
21 October 2010, 12:42 PM
#2
MAF most likely, to test it do the following
When the car is idling unplug the MAF...if the car cuts out it is not the maf. If the car continues to run then the MAF is buggered.
When the car is idling unplug the MAF...if the car cuts out it is not the maf. If the car continues to run then the MAF is buggered.
21 October 2010, 03:47 PM
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No it isn't Muttley. I appreciate you probably mean well but your "test" is complete bullsh*t, proves nothing, and also has a small potential to damage both the ECU and an otherwise good airflow meter. It is certainly not capable of accurately demonstrating the difference between a damaged sensor and a good one. Please do yourself and everyone else a favour and stop suggesting it, it is bad advice and utterly unhelpful. If you want to know why, hit the search button.
AsaTDi, as per your original post and the responses other than Muttley's, there are a number of potential causal factors, but the one to rule out first would certainly be the airflow meter, as if this has gone, the engine is likely running outside a safe performance envelope.
If the DV is either sticking or the spring tension is set wrong - to the point that it can open at idle vacuum, this is the type of symptom you can end up with.
One thing nobody's asked you yet: Have you tried doing an error check on the ECU (the black plugs), or have you noticed the Check Engine light come on during normal driving? If you haven't checked the memory yet, do so now and tell us any stored error codes.
One test procedure you can try would be to get the engine nicely warmed - and to a point where the misbehaviour is obvious, switch off, then disconnect the airflow meter, and then restart the engine. You will see the Check Engine light. Drive around at nothing more than parking speeds, starting and stopping, and ask yourself whether the behaviour of the engine is noticeably improved/changed. If it has, this is a strong indication (not 100% confirmation you notice) that the airflow meter is badly degraded, and that a replacement is in order. Either way, stop the engine, and reconnect the airflow meter.
If there is no change at all to the symptoms when you are running in this state, this is a strong indication that the problem is elsewhere. However, do not assume that the airflow meter is in the clear until you know it is. While you are still suspicious of it, do not drive under boost at all, unless you want to risk potentially serious engine damage.
If you have cause to replace the AFM, the part number is 22794AA010, available for something over a hundred quid at a Subaru main dealer, something less than that at Import Car Parts, among other places.
As far as the dumpvalve is concerned, the best way to "test"/rule that out would be to refit an OE Subaru one. Your engine will likely perform better with it than with the aftermarket part.
AsaTDi, as per your original post and the responses other than Muttley's, there are a number of potential causal factors, but the one to rule out first would certainly be the airflow meter, as if this has gone, the engine is likely running outside a safe performance envelope.
If the DV is either sticking or the spring tension is set wrong - to the point that it can open at idle vacuum, this is the type of symptom you can end up with.
One thing nobody's asked you yet: Have you tried doing an error check on the ECU (the black plugs), or have you noticed the Check Engine light come on during normal driving? If you haven't checked the memory yet, do so now and tell us any stored error codes.
One test procedure you can try would be to get the engine nicely warmed - and to a point where the misbehaviour is obvious, switch off, then disconnect the airflow meter, and then restart the engine. You will see the Check Engine light. Drive around at nothing more than parking speeds, starting and stopping, and ask yourself whether the behaviour of the engine is noticeably improved/changed. If it has, this is a strong indication (not 100% confirmation you notice) that the airflow meter is badly degraded, and that a replacement is in order. Either way, stop the engine, and reconnect the airflow meter.
If there is no change at all to the symptoms when you are running in this state, this is a strong indication that the problem is elsewhere. However, do not assume that the airflow meter is in the clear until you know it is. While you are still suspicious of it, do not drive under boost at all, unless you want to risk potentially serious engine damage.
If you have cause to replace the AFM, the part number is 22794AA010, available for something over a hundred quid at a Subaru main dealer, something less than that at Import Car Parts, among other places.
As far as the dumpvalve is concerned, the best way to "test"/rule that out would be to refit an OE Subaru one. Your engine will likely perform better with it than with the aftermarket part.
Last edited by Splitpin; 21 October 2010 at 03:48 PM.
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21 October 2010, 03:54 PM
#8
No it isn't Muttley. I appreciate you probably mean well but your "test" is complete bullsh*t, proves nothing, and also has a small potential to damage both the ECU and an otherwise good airflow meter. It is certainly not capable of accurately demonstrating the difference between a damaged sensor and a good one. Please do yourself and everyone else a favour and stop suggesting it, it is bad advice and utterly unhelpful. If you want to know why, hit the search button.
AsaTDi, as per your original post and the responses other than Muttley's, there are a number of potential causal factors, but the one to rule out first would certainly be the airflow meter, as if this has gone, the engine is likely running outside a safe performance envelope.
If the DV is either sticking or the spring tension is set wrong - to the point that it can open at idle vacuum, this is the type of symptom you can end up with.
One thing nobody's asked you yet: Have you tried doing an error check on the ECU (the black plugs), or have you noticed the Check Engine light come on during normal driving? If you haven't checked the memory yet, do so now and tell us any stored error codes.
One test procedure you can try would be to get the engine nicely warmed - and to a point where the misbehaviour is obvious, switch off, then disconnect the airflow meter, and then restart the engine. You will see the Check Engine light. Drive around at nothing more than parking speeds, starting and stopping, and ask yourself whether the behaviour of the engine is noticeably improved/changed. If it has, this is a strong indication (not 100% confirmation you notice) that the airflow meter is badly degraded, and that a replacement is in order. Either way, stop the engine, and reconnect the airflow meter.
If there is no change at all to the symptoms when you are running in this state, this is a strong indication that the problem is elsewhere. However, do not assume that the airflow meter is in the clear until you know it is. While you are still suspicious of it, do not drive under boost at all, unless you want to risk potentially serious engine damage.
If you have cause to replace the AFM, the part number is 22794AA010, available for something over a hundred quid at a Subaru main dealer, something less than that at Import Car Parts, among other places.
As far as the dumpvalve is concerned, the best way to "test"/rule that out would be to refit an OE Subaru one. Your engine will likely perform better with it than with the aftermarket part.
AsaTDi, as per your original post and the responses other than Muttley's, there are a number of potential causal factors, but the one to rule out first would certainly be the airflow meter, as if this has gone, the engine is likely running outside a safe performance envelope.
If the DV is either sticking or the spring tension is set wrong - to the point that it can open at idle vacuum, this is the type of symptom you can end up with.
One thing nobody's asked you yet: Have you tried doing an error check on the ECU (the black plugs), or have you noticed the Check Engine light come on during normal driving? If you haven't checked the memory yet, do so now and tell us any stored error codes.
One test procedure you can try would be to get the engine nicely warmed - and to a point where the misbehaviour is obvious, switch off, then disconnect the airflow meter, and then restart the engine. You will see the Check Engine light. Drive around at nothing more than parking speeds, starting and stopping, and ask yourself whether the behaviour of the engine is noticeably improved/changed. If it has, this is a strong indication (not 100% confirmation you notice) that the airflow meter is badly degraded, and that a replacement is in order. Either way, stop the engine, and reconnect the airflow meter.
If there is no change at all to the symptoms when you are running in this state, this is a strong indication that the problem is elsewhere. However, do not assume that the airflow meter is in the clear until you know it is. While you are still suspicious of it, do not drive under boost at all, unless you want to risk potentially serious engine damage.
If you have cause to replace the AFM, the part number is 22794AA010, available for something over a hundred quid at a Subaru main dealer, something less than that at Import Car Parts, among other places.
As far as the dumpvalve is concerned, the best way to "test"/rule that out would be to refit an OE Subaru one. Your engine will likely perform better with it than with the aftermarket part.
The reason I responded as I did, as this is what I've been told, I agree if you are correct I haven't searched it in depth enough but I've been told what I said quite a few times.
Anyway to the thread starter, I hope you get it sorted and apologies if the advice I gave isn't the best. I was just going off what I have been told before.
21 October 2010, 04:08 PM
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The reason I used the wording the way I did is because you came back a second time with your "it's fine" comment despite Asa clearly having heard otherwise. As I said up front, I appreciate you mean well, but this "advice" is dangerous, and can easily lead to some poor innocent following it and consequently breaking their engine. The best way to deal with bullsh*t is to call it what it is, and the reason I put "test" in inverted commas is because the only thing it tests is the ability of people to blindly do what people tell them without thinking.
Last edited by Splitpin; 21 October 2010 at 04:09 PM.
21 October 2010, 04:13 PM
#10
I've read what I advised a few times from various people however( I can find various threads on here and other forums telling people to do the same thing)...im putting my hand in the air and admitting it clearly isn't the right procedure to take to test the MAF...you are obviously more informed than me and I respect that.
I don't think you would speak to someone like that in real life so don't do it on here because its words on a screen. Anyways lets not ruin a thread by bickering, as the OP needs to get his car sorted.
I don't think you would speak to someone like that in real life so don't do it on here because its words on a screen. Anyways lets not ruin a thread by bickering, as the OP needs to get his car sorted.
23 October 2010, 09:31 AM
#13
Theres one here for sale if your interested on ebay ,failing that try the for sale section on here :
http://cgi.ebay.co.uk/SUBARU-IMPREZA...item255e07418c
The turbo xs dump valve you have as mentioned above is worth changing back to std as apart from looking to big for the engine bay imho,they can not be adjusted and the springs are made of butter.
http://cgi.ebay.co.uk/SUBARU-IMPREZA...item255e07418c
The turbo xs dump valve you have as mentioned above is worth changing back to std as apart from looking to big for the engine bay imho,they can not be adjusted and the springs are made of butter.
Last edited by midnight; 23 October 2010 at 09:40 AM.
23 October 2010, 12:56 PM
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same with my friends my98 iratic idle and stalling, he changed his forge dv for my OE one and it cured it instantly, the spring was knackered in the vta dv, but till he gives it back im stuck with a turd baileys dv! not cool!
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