Lexus IS Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
7,824 Posts
Discussion Starter #1 (Edited)
Hey guys,

I was wondering what readings people were getting with the kits running off the stock ecu. I've basically got the TE S1 kit and my a/f's are all over the place. I know that the kit runs rich without tuning but I wasn't sure if a/f's are supposed to be jumping around like mine do or stay more constant.

Under boost I'm waaaaay rich, hitting 10.0 under full boost (keep in mind its colder weather (30s), but sunday was 65 degreesand under full boost I hit 10.2-10.5)

Anyways under normal driving the afr is jumping around from 12s to 16s and I don't think that should be normal.

Could it be a fouled wideband sensor, and maybe it just needs cleaned / replaced?

I tried looking around but couldn't find anyone having a similar problem, at least not thread wise.
 

·
Premium Member
Joined
·
4,978 Posts
With the stock ECU and just the TE black box your AFRs might jump around a lot. When I was running a Black Box with the SAFCII the AFRs would jump around only in vacuum (closed loop). Once you hit boost and the stock ECU goes into open loop operation the AFRs will stay steady allowing for another form of management to control the AFRs aka your TE Black Box. That is one very nice thing about a standalone to control everything without relearning. I think some of that has to do with the stock ECU relearning too to where the AFRs want to jump around. Does your Black Box reset the ECU when you pull the key or every "x" amount of driving and when you pull the key?
 

·
Registered
Joined
·
7,824 Posts
Discussion Starter #4
I heard you can clean it with brake cleaner, anyone else heard that?

So if the sensor is bad it could mean that I'm running fine and the sensor is just going funky?

I think some of that has to do with the stock ECU relearning too to where the AFRs want to jump around. Does your Black Box reset the ECU when you pull the key or every "x" amount of driving?
I'm pretty sure it just resets after I turn the car off.
 

·
Premium Member
Joined
·
4,978 Posts
Then your ECU could be relearning after even a 20 mile to 60 mile drive. I had the same issues with the AFRs jumping around after relearning of the ECU. Closed loop and vacuum was like that for me. It wasn't that big of a deal but sometimes it would have a hiccup here or there. Under boost though everything was right on par. I would suggest leaning your AFRs out under boost to something like 11:1 - 11.8:1 (Maybe with an SAFCII or E-Manage Ult.?) I thought there was also a black box that continuously reset the fuel trims even while driving to prevent any relearning? I know guys have said that there is a way to tune with an SAFCII and keep the fuel trims within certain designated ranges and there will be no learning at all.
 
  • Like
Reactions: kaptain86

·
Registered
Joined
·
7,824 Posts
Discussion Starter #6
I don't have the black box per say, its a type of relay that resets the ecu when the car is shut off, so maybe the part about relearning during driving is my problem. I don't have anything to tune it with right now but I might be able to adjust the rising rate fuel regulator to lean it out some.
 

·
Premium Member
Joined
·
4,978 Posts
I think so bro as I had that same problem... Just the PFS ECU relay coupled with an SAFCII.
 

·
Registered
Joined
·
2,181 Posts
what size pipe is MAF sensor on? I was having the same issues as you. I was using the 3 inch pipe where the maf sensor sits, my AEM wideband reading was all over the place. I was constantly changing my SAFC setting trying to get everything happy. I then changed the pipe to 2.75 inches (LMS CAI works perfect) and new spark plugs. everything is running good now. I still need to fine tune it but my AFR is at about 14.6-15.6 and its consistant. boost is like 10s and 11s which needs to adjusted
 
1 - 9 of 9 Posts
Top