slight surge in steady throttle
#1
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Trying to get my mind away from tb993tt's "new" car and all those fab pictures...
My car has a slight surge at steady throttle, most noticeable between perhaps 2000 and 4000 rpm at most road speeds. It feels like someone is making very small throttle adjustments in a fairly rythmic manner. The MAF is about 3 years old and plugs about a year. No codes in the ECU. Any suggestions on where to look for issues?
My car has a slight surge at steady throttle, most noticeable between perhaps 2000 and 4000 rpm at most road speeds. It feels like someone is making very small throttle adjustments in a fairly rythmic manner. The MAF is about 3 years old and plugs about a year. No codes in the ECU. Any suggestions on where to look for issues?
#2
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hmmm small boost leak maybe? If that was the case you notice something under WOT. Also give the Maf a quick clean and see if the problem persisits. Bosch Mafs should be considered a long term consumable in any car and it may be time for a new one. Does your boost do anything funny? I've had N75's got bad before
Being that there are no codes thats where I would start. Good luck!
Being that there are no codes thats where I would start. Good luck!
#3
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ISV mate ISV, Idle Speed Valve
Need to spray a spray of WD40 inside, and you're good to go,
read on normal aspirated forum, classic issue
Need to spray a spray of WD40 inside, and you're good to go,
read on normal aspirated forum, classic issue
#4
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OK, I spoke too soon. There's no CEL but there are codes as follows:
Fault Number:16 - P0133
Description:Sensor ageing ahead of cat.
Repair Infomation:conv. conv. cylinder (1-3)
Fault Number:17 - P0139
Description:Sensor ageing behind cat.
Repair Infomation:conv. cylinder (1-3)
Fault Number:22 - P0153
Description:Sensor ageing ahead of cat.
Repair Infomation:conv. cylinder (4-6)
Fault Number:23 - P0159
Description:Sensor ageing behind cat.
Repair Infomation:conv. cylinder (4-6)
Fault Number:12 - P0136
Description:O2 sensor behind cat. conv.
Repair Infomation:Cylinder (1-3)
Fault Number:20 - P0156
Description:O2 sensor behind cat. conv.
Repair Infomation:Cylinder (1-3)
So the ECU and my O2 sensors aren't getting along very well! The post-cat O2 sensors are hanging out in the breeze as I still have two wideband lambda sensors installed as part of my datalogging fun and games. And the pre-cat O2 sensors are only about 2 years old. I have cleared the codes and will take the car for a run.
Fault Number:16 - P0133
Description:Sensor ageing ahead of cat.
Repair Infomation:conv. conv. cylinder (1-3)
Fault Number:17 - P0139
Description:Sensor ageing behind cat.
Repair Infomation:conv. cylinder (1-3)
Fault Number:22 - P0153
Description:Sensor ageing ahead of cat.
Repair Infomation:conv. cylinder (4-6)
Fault Number:23 - P0159
Description:Sensor ageing behind cat.
Repair Infomation:conv. cylinder (4-6)
Fault Number:12 - P0136
Description:O2 sensor behind cat. conv.
Repair Infomation:Cylinder (1-3)
Fault Number:20 - P0156
Description:O2 sensor behind cat. conv.
Repair Infomation:Cylinder (1-3)
So the ECU and my O2 sensors aren't getting along very well! The post-cat O2 sensors are hanging out in the breeze as I still have two wideband lambda sensors installed as part of my datalogging fun and games. And the pre-cat O2 sensors are only about 2 years old. I have cleared the codes and will take the car for a run.