Idle AFR slowly drops to 10.5 while warming up
#1
New Member
Thread Starter
Idle AFR slowly drops to 10.5 while warming up
When starting my car, the idle AFR is at 14.7, but as it warms up, it slowly drops until it reaches 10.5.
I noticed both the upstream O2 sensors were always reading 0.01V at idle so I replaced both of them. The car still runs rich and the O2 sensors still read 0.01V.
I tried:
Cleaning the throttle body
Cleaning the MAF sensor
Checking the PCV valve
Idling with the air filter off
The spark plugs and ignition coils are only a year old.
I also tried idling with the PCV hose disconnected to introduce a vacuum leak. The idle afr went to 14.7 and the rpm jumped to about 1200.
This issue just came up while driving and will try to bog the engine down to 400 rpm when at a stop in drive so I need to give it gas so the car doesn't shut off.
This happened a day after I fixed my transmission slipping issue:
https://my350z.com/forum/2003-2009-n...-slipping.html
I don't see any way it could be related but this issue did happen a day after fixing the transmission issue.
I noticed my vacuum at idle in drive is reading at 13.7hg with an OBD scanner and 17hg on my boost gauge.
I noticed both the upstream O2 sensors were always reading 0.01V at idle so I replaced both of them. The car still runs rich and the O2 sensors still read 0.01V.
I tried:
Cleaning the throttle body
Cleaning the MAF sensor
Checking the PCV valve
Idling with the air filter off
The spark plugs and ignition coils are only a year old.
I also tried idling with the PCV hose disconnected to introduce a vacuum leak. The idle afr went to 14.7 and the rpm jumped to about 1200.
This issue just came up while driving and will try to bog the engine down to 400 rpm when at a stop in drive so I need to give it gas so the car doesn't shut off.
This happened a day after I fixed my transmission slipping issue:
https://my350z.com/forum/2003-2009-n...-slipping.html
I don't see any way it could be related but this issue did happen a day after fixing the transmission issue.
I noticed my vacuum at idle in drive is reading at 13.7hg with an OBD scanner and 17hg on my boost gauge.
Last edited by Faasnu; 07-15-2018 at 04:19 PM.
#2
New Member
Thread Starter
I bypassed the supercharger and idle afr went to normal so it seems like a blow off valve issue
Edit:
Took off blow off valve, issue still present
Edit:
Took off blow off valve, issue still present
Last edited by Faasnu; 07-15-2018 at 05:51 PM.
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