wrx low idle / stalling issue
#1
wrx low idle / stalling issue
this will be my first post in this subforum.
anyways, i put on a front mount like 2 months ago. it ran fine until after a week of driving when it would suddenly stall out or idle really low. for example, if i am driving and throw it into neutral itll hit 0 rpm then bounce up to 750 rpm most of the time but a few occurrences it has stalled on me while driving! sometimes it decides to idle below 750rpm like around 600 or so it seems. also, if i have the clutch in with 1st gear engaged, if i give it throttle it will want to stall out unless i constantly give it gas. my temporary solution has been to reset the ecu which gives me about a week of normal idle behavior until it happens again.
i did some wot pulls and heard a leak so i went over all my fmic couplings and made sure they were TIGHT and the sound went away. however, the problem still occurs
the relevant mods on my car are:
2004 subaru wrx
catless turboback
catless uppipe
turboxs short ram intake
stock turbo
stock bpv
ssac fmic
xpt tuning stage 2 OPENSOURCE ecu map. this map is meant for a large TMIC but i dont see how a fmic would cause this
thats about it performance wise.
ive narrowed it down to several things:
1) leak - double checked for leaks as mentioned earlier. from a hearing stand point i dont hear anything but i think the next thing i will do is a boost leak test...
2) dirty maf sensor/intake filter - cleaned it, made no difference
3) dirty IACV (idle air control valve) sensor - cleaned it, made no difference
4) needs tuning - possibly? but i know several people who run stock turbos untuned with a FMIC and dont have this issue.
5) too lean at idle - ive attached some logs with AFRs and other relevant data for you to see.
wrx at idle:
http://spreadsheets.google.com/ccc?k...zxb_KtUg&hl=en
wrx with a few blips of the throttle to show the idle dropping down to 400 rpms:
http://spreadsheets.google.com/ccc?k...45hy8FTw&hl=en
im honestly lost here. any insight would be appreciated.
alan
anyways, i put on a front mount like 2 months ago. it ran fine until after a week of driving when it would suddenly stall out or idle really low. for example, if i am driving and throw it into neutral itll hit 0 rpm then bounce up to 750 rpm most of the time but a few occurrences it has stalled on me while driving! sometimes it decides to idle below 750rpm like around 600 or so it seems. also, if i have the clutch in with 1st gear engaged, if i give it throttle it will want to stall out unless i constantly give it gas. my temporary solution has been to reset the ecu which gives me about a week of normal idle behavior until it happens again.
i did some wot pulls and heard a leak so i went over all my fmic couplings and made sure they were TIGHT and the sound went away. however, the problem still occurs
the relevant mods on my car are:
2004 subaru wrx
catless turboback
catless uppipe
turboxs short ram intake
stock turbo
stock bpv
ssac fmic
xpt tuning stage 2 OPENSOURCE ecu map. this map is meant for a large TMIC but i dont see how a fmic would cause this
thats about it performance wise.
ive narrowed it down to several things:
1) leak - double checked for leaks as mentioned earlier. from a hearing stand point i dont hear anything but i think the next thing i will do is a boost leak test...
2) dirty maf sensor/intake filter - cleaned it, made no difference
3) dirty IACV (idle air control valve) sensor - cleaned it, made no difference
4) needs tuning - possibly? but i know several people who run stock turbos untuned with a FMIC and dont have this issue.
5) too lean at idle - ive attached some logs with AFRs and other relevant data for you to see.
wrx at idle:
http://spreadsheets.google.com/ccc?k...zxb_KtUg&hl=en
wrx with a few blips of the throttle to show the idle dropping down to 400 rpms:
http://spreadsheets.google.com/ccc?k...45hy8FTw&hl=en
im honestly lost here. any insight would be appreciated.
alan
#2
Racetracks
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Re: wrx low idle / stalling issue
Put the stock intake back on and try that. There are a lot of problems with aftermarket intakes unless you've had your car tuned after the install.. The stock ECU is very sensitive to differences in MAP and MAF sensor readings from flow velocity changes with non-stock intakes. It's an odd but well known quirk. It's obvious that the ECU is learning some type of non-normal sensor behavior, you just have to find out what it is.
There may be a difference in pressure drop across the new intercooler too, and that may be freaking the ECU out too. I don't remember if there is a MAP sensor before the intercooler somewhere, but that would do it (the ECU will be comparing pressure before and after the IC).
There's some stuff to start thinking about.
Also, if you've got rid of your cats, and haven't done anything with the O2 sensors, that will have some effect. Without knowing a lot more about that tune you have, it's hard to say. You really should get a tune though, the stock ECU is very nice but sensitive to engine changes so it probably needs to get tuned for those changes.
You haven't switched to a lightened flywheel, have you?
There may be a difference in pressure drop across the new intercooler too, and that may be freaking the ECU out too. I don't remember if there is a MAP sensor before the intercooler somewhere, but that would do it (the ECU will be comparing pressure before and after the IC).
There's some stuff to start thinking about.
Also, if you've got rid of your cats, and haven't done anything with the O2 sensors, that will have some effect. Without knowing a lot more about that tune you have, it's hard to say. You really should get a tune though, the stock ECU is very nice but sensitive to engine changes so it probably needs to get tuned for those changes.
You haven't switched to a lightened flywheel, have you?
#3
Re: wrx low idle / stalling issue
i ran the intake for a few months and my car ran fine.
i have the rear o2 sensor plugged in as well.
im stock flywheel.
i really need to get a leak test done. if that shows everything is a-ok, then ill just buy new turbo and etc then get tuned
i have the rear o2 sensor plugged in as well.
im stock flywheel.
i really need to get a leak test done. if that shows everything is a-ok, then ill just buy new turbo and etc then get tuned
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