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View Full Version : Help: Sr20det now began to idle lean


Trinidrift3
01-01-2015, 04:16 PM
1st off thanks for reading and giving any type of helpful comments
-i do not drive much or for long distances

-i was driving Christmas eve and at a stoplight i saw my idle afr was 17:1 or reading full lean (---). normally it was 14.5-15.5:1

-headed straight home. i drove to the next stoplight and held the throttle open a bit to rich it up a little while i waited. as i pulled off it stalled in the intersection and would not restart

- i pushed it to a parking lot, popped the hood and looked around for 30secs. went back in and it started right up. drove home and parked it

-ever time i start it from cold it goes to 13:1, as it warms up it slowly drops full lean. at operating temp it idles around 16.5:1 to ---

-boost/vacuum gauge shows -20hg at idle

-changed fpr and fuel filter. pulled walbro 255 and hardwired to make sure it ran smooth.

-fuel pressure is 40psi at idle with vacuum on fpr. if i start it without fpr vacuum it's 50psi and idles everywhere

- at idle it does not misfire and revs up normal. im pretty sure its not a bad wideband sensor because the exhaust sounds poppy which indicates lean. drove it around the block fine so it is driveable

Any idea on what i could be, or where to search? people keep saying vacuum leak but i haven't found one. im completely stumped right now and resorted to making a thread for this.
car has redtop sr20det, apexi pfc, stock injectors in, walbro 255, z32 fuel filter

Javi802
01-01-2015, 04:21 PM
edit.........

jcanady
01-01-2015, 04:23 PM
Check your O2 sensor for shits and giggles.

ultimateirving
01-01-2015, 04:25 PM
Yeah as random as it started it could be an exhaust leak. Unburnt fuel can also cause a lean condition. If she runs pretty normal it's not likely but you could have a vacuum leak too

Javi802
01-01-2015, 04:27 PM
What he said^

Or an exhaust leak before the o2 sensor

unburnt fuel would cause it to run rich

Check your MAF as well