Esh Darkstar

I want to get some opinions on what could be causing some codes I've been getting. (and before someone says use the search button, have, no joy.)

0301 (misfire cylinder 1)
0335 (Crankshaft Position Sensor A Circuit Malfunction)
0505 (Idle control system malfunction)
0171 (fuel system too lean)

0420 (Catalyst System Efficiency Below Threshold) For legal sake lets just say the car is for track/off-road use only at this point.

This is an 08 that has a Dezod turbo kit and has been dyno tuned (little over 300hp and 300ftlb at the wheel). The plugs are NGK Iridium BKR8EIX with a .029 gap.

The 0301 is the most common along with the 0420. I get these codes just about every other time I drive the car. I don't actually feel the misfire but talking with some of my friends about that code I've been told that it could be that you won't feel it especially if it happens at idle and only just enough to set the code off. I get the 0505 about every third or fourth code trip (but it can be as much as a dozen code trips) along with the 0335. These two codes usually involve a limp mode event(CEL flashing) at which point I quickly get off the road shut the car off, read and record the codes then restart the car and continue driving. The 0171 came up only once and that was when I had no choice but to drive the car a significant distance in limp mode.

Now the MAF was replaced right before the tune and I pretty much have been receiving these codes since then.

I'm kind of at a lost for ideas on what could be causing this and I'm wondering if the tune could be the problem for it. I've been told there is a check box in the AEM/FIC that can make the 0420 code go away but I'm not sure if that's really true. The 0301 seems to be tied into the 0420 so my money is that the two are linked. The 0171 and the 0505 the only commonality they seem to have is with me trying to accelerate from stop (and I can't reproduce it). I was told by the company that did the tuning that I would have problems with partial throttle acceleration because the BOV vented into atmosphere and back into they intake beyond the MAF and that I should buy the adapter kit to make that change. Of course they offered to install it for me for a reasonable fee. I turned them down on that offer since every photo of a turboed tC I've seen doesn't have this modification and I can't see Dezod putting a kit together that you would have to mod.

So that's what I got, subject to your questions what do y'all think? Need to retune or am I missing something?

borderguy881

iTrader: (-1)

first thing first, is the aem plugged in using a PLUG N PLAY harnes?

2. the crank shaft and misfire codes im certain are related with you needing resistors on your aem fic wiring

3. idle control? could have a sort of vac leak or a stuck bov? but dont pin it on just that yet ill explain later

4. having your bov venting to atmoshpere has nothing to do with partial throttle (its all in the tune) the bov will just make it so you run rich and bog between shifts or everytime the bov vents (which can be tuned out)

5. when a CEL flashes on our cars its experiencing misfire(check resistor)

6. judging by the tuner telling you false information, the car reading system too lean, and the idle control issues, id say you need a new tuner they def dont have much experience with either the fic or the tc

Dkfung88

agreed with what was said on top..

the crankshaft code most likely is part of the resistor on the harness..

lean, misfire, and idle really does sound like a tuning problem. my car was running lean and was misfiring when it was not tuned. I would try another tuner and see if they're able to fix the problem. I have dealt with some pretty reputable tuners but each one only knows so much...

Esh Darkstar

The harness is a plug n play built by Dezod. I'll do a search a little later about the resistor mod but I would assume that coming from Dezod that if it was needed it would have been done by them. I know assumptions are a ****.

I'll check the vac system again but I didn't find anything wrong the last couple times I checked it. I am running a gauge on it and the idle reading is between 18 and 20 negative. Under heavy acceleration it will get upwards of 8 positive but I've been told that is expected. Of course that's when I don't get the code. Question: is there anything in the vacuum system, out side hoses, that could be damaged in such a way that it will release the vacuum system after the engine is at temperature?

I had my doubts about the tunner when I used him as it took him half a day to figure out that some check box was set to the wrong position. Now it seems I'm stuck trying to find another shop. Just on a long shot does anyone know of a respectable tuner in the Raleigh NC area?

Tracking on the Oxygen Sensor Spacer

thendawg

iTrader: (2)

Crankshaft code is probably not having a resistor in the crank/cam wiring on the FIC. 0420 is harmless, it will literally affect nothing. I dont even have a second 02 sensor hooked up, it does nothing, I promise. (Other than cause the CEL to turn on and you to fail emissions if you have state inspection) The lean and misfire are probably related - if the car runs too lean or too rich under heavy throttle it can cause a misfire. The idle control code could only be something interfering with the throttle body wiring. The only thing you should have connected here is TPS. Look at the real time data in the FIC and press the pedal with ign on only (car not started) and make sure your TPS value looks normal.

borderguy881

iTrader: (-1)

Tuner may have tuned using the new software allowing the use of throttle position for tuning and may have skewed something in the idle portion