Hey guys I’m having some problems with my 2006 turbo Scion tC its running very lean, and has a check engine light on for misfire on every cylinder as well as a random misfire. I’m trying to put the car back to stock in order to trouble shot the problem. I am running the Turbonetics kit with a GSP manifold 550cc injectors with the AEM FIC controller. I believe on my map I am adding 15% at idle, my short trim is 0-3 my AFR is --- Lean off the gauge. At cruzing with a load on the car my AFR is in the 16’s high 15’s. Apon starting the car its reads rich very quick then holds 14.7 then back to 14.7 holds for a few seconds then very slowly goes lean ---.

For any one that says its tune related it’s NOT!!!


First I checked my Fuel pressure inline with the rail I had 50psi


Then I swapped the front O2 sensor…


I started the car with the O2 sensor outside of the exhaust to make sure it was getting hot. I was with the O2 sensor outside of the exhaust the car ran exactly the same.


Screwed in the front O2 sensor still with the FIC and 550CC injectors and started the car at idle was running high 16’s low 17’s



Putting the car back to stock…


Pulled the 550cc injectors and put in 360cc Stock injectors started car with FIC no change.


Disconnected the FIC ran the car as if it was stock!!! Started the car with Stock ECU and Stock 360cc injectors. The car did the same thing as it had been doing but my short trim was 20% and my AFR was still --- lean off the gauge.


I have also replaced my Wideband O2 sensor it’s brand new and checked with a sniffer to make sure it matched up the Wideband is working perfected.


Iv swapped MAP sensors with no change
Iv swapped ECU with no change
I also did a smoke test and a boost leak check finding none
Iv swapped back to stock fuel pump no change then back to the bigger one


I’m out of ideas on what could be making my car run so lean it’s basically a FACTORY car with a turbo in the exhaust it should be running 14.7 with no problem but its NOT…

 

At fist I thought it was a fuel related problem because I heard a loud clicking sound coming from the fuel rail area after I cycled my car and my fuel pump was on. With my hand on I believe its the fuel dampener it has the white hat attached to the fuel rail i could feel the clicking. I swapped out the rail and dampener and went to stock injectors it still made the same sound... I have checked the fuel pressure in the rail its at 50psi.
I checked other ppl tC and theirs doesn't make that sound IDK if its related or not...

Attached is a clip of the sound it makes

 

That sound sounds like the aem fic.

Usually happens with automatic turbo tcs.

https://www.scionlife.com/forums/sho...d.php?t=210269

 

I've ran my car with out the fic with stock injectors and stock ecu

 

Bump for help

 

Check your manifold and downpipe to make sure that they aren't cracked. Also make sure that all bolts on the whole assembly are torqued down sufficiently. Finally check any gaskets that are before the o2 sensor, along with checking the o2 sensor itself to make sure its torqued down also. Any sort of exhaust leak before the o2 will make the o2 read lean.

 

This is what I had in mind reading the original post along with injector latency, but if it's the same with stock ecu and injectors that rules out latency I suppose. My guess is bad O2 sensor. My buddy had this problem but instead his was off the gauge rich. Swapped the O2 and it fixed it.

 

Check your downpipe to s-pipe connection. My AFR's were lean like this at one point too and it turned out I lost a spring and nut that held the two together and had a massive exhaust leak b4 the wideband. It was basically reading as if it was out of the exhaust stream.