So i just put my turbo kit in this past weekend and got it all set. If this makes any difference i bought it used and everything seems to be working alright.

The problem is the AFR's are constantly jumping between 13-16 just cruising and when i let off the gas it goes all the way to the right like past 18. Even at idle it is jumping from like high 13's to like 15.5. sometimes jumping to the 17's.

I am running off the tune that the previous owner had, just for now. I was just wondering what this might mean. I don't get that bad of back firing maybe once in a great while. I also have the stock plugs in, but not for long. I have only takin it on one real ride so far and i just got the colder plugs and will be putting them in ASAP, but not sure if this is my problem. I will also be getting it re-tuned for my car.

Just wondering what the problem is and if any of the things i have yet to do will fix it. Or is it something serious.


ALSO! just to throw this out there but if there is anybody in the RI area that could help me install my turbo timer that would be awesome. Right now I'm just letting it idle for like 8-10 mins

 

sounds like a major vac leak to me...

 

8-10 minute IDLES???? hahah thats too long for our cars at such low boost levels.. 1-2 mins tops!

 

but my car idles fine. the rpms don't move that much. and i don't stall.

 

Just a minute is fine if you're boosting a lot.

I don't do it if I haven't boosted.

 

haha yeah i guess it is. i was just playing it safe.

 

try clear your fuel trims.. unplug the neg terminal of your battery for like 30 seconds then put it back.. might work..

what management? pnp harness?

 

AEM FIC with pnp harness. I have already reset my computer once but i'll try it again. I'm open to all ideas!

 

hmmm.. it has to be tune related... i suggest getting tuned and let the tuner know about the issue.. then it should be fine.

 

i hope so! if anybody has any ideas please let me know.

 

good luck.. should be the tune though.

 

you're fine, i guarentee that it's a tuning issue.

 

so is it safe to drive it for a little while? i won't be pushing it at all because i havent even put my clutch it yet.

 

what gauge do u have? aem digital?
if so i have the same thing.. my afrs are everywhere.. nothin to wory about tho

 

Depending on how wide they swing its normal, when the car is in closed loop mode it uses data from the 02 sensor to correct the afr. So in essence what happens is your ecu and piggyback tell the car to inject a certain amount of fuel which gives you a resulting afr of say 14.0, than the computer realizes this is rich and corrects by leaning out and jumping it up to 15 or so, than back to rich to correct for that, etc. If its too wide, your fuel trims are probably set to high in the fic for vacuum (cruising) thus the factory ecu and o2 sensor is having to overly correct causing very large jumps, if the fuel trims under vacuum are off ive seen it swing from 13.5 to 16 and back and forth over and over

 

whats the ideal afr at wot for the scion tc anyway?

 

Depends on what you're going for.. if you're looking for street drivability and safety on a boosted TC, then you want to stay 11.5 and lower (richer). If you're looking for more power and have total control of your engine (really good tuning and a racing environment), you may want to be closer to the 12 to 12.5 range.

 

i see thanks

 

yeah it should be tune related, and plus a BOV vented to atmosphere could add to that.. as long as it doesnt stay lean when you hit boost you should be good, what you should keep your eyes on is the boost afrs since you are untuned dont let it stay above 12.5 when you boost

 

yeah i reset my ecu and it seems to hold steady at like 13.6ish at idle and it does go lower during boost but i tend to keep my eyes more on the road haha. At cruising it also tends to stay in the 13's. Occasionally it will jump around but only a little. Also when i let off the gas and still in gear the gauge goes all the way to the right and the three dots come up is that normal? Also i can hear my turbo spooling before my boost gauge is even at 0. j/w if this is norm. It's my fist time boosting a car and i am a little nervous... as you might be able to tell. Just wanna make sure nothings wrong.