My car is a 2004.5 5AT G35 coupe (NA). Just installed new UTEC (checked software v 2.8). I have installed proper grounds and have the map switch on the UTEC set at 0. I have the remote MAP switch installed and it is also set at 0.

All I've done is turn car on to idle and turn off because it was running too rich w/ A LOT of gas fumes.

I have CIPHER and it reads bank 0 w/ AFR 15 but bank 1 has an AFR of 11 at idle.

What is up with that? Any suggestions?

My next stage was to install the turboxs tuner reg but I want to find out what's wrong here before I go messing around under the car w/ another o2 sensor...

THANKS!

 

really weird problem. I would ask you to check your wiring, but isn't the UTEC pre-wired? Even so... you probably have either a physical problem with an injector (or more than 1)... but if you can remove the UTEC and the problem goes away, it could be a damaged wire

Use cipher to plot the injector pulse ...... at idle it should be like 6-8ms (I could be wrong though??)

 

Since the car is NA you should be able to remove the UTEC and drive around with no major tuning issues.

I would do this, and see if the problem goes away.

The UTEC doesn't offer individual injector changes, so I can't see how the tuning of the UTEC would cause this problem. However, if an injector output is faulty it could be dumping fuel at all times. Eliminating the UTEC from the picture will at least let you know if the problem is with the UTEC or with your wideband. From your 'smells rich' observation I would say the sensor isn't the problem, but this way you can prove that.

 

If an injector is 'stuck' open (or a UTEC output is stuck closed) the Cipher won't show the fault. It will show what the injector is supposed to be doing, but isn't smart enough to know what the injector is actually doing.

 

double post

 

Ok, so I hooked the stock ECU back up. Same thing - rough idle, thick smoke out of the driver's side exhaust (I have a true dual) and tons of toxic fuel vapors. WTH!

So I traced my steps back - the only difference was I had my stock ECU bracket removed to get the UTEC to fit in there nicely in my G35. I used an ohm-meter to check the casing of the UTEC/stock ECU w/ chassis ground. NOTHING! I had the ground plug from the UTEC molex connector hooked up. Again WTH? The UTEC chassis is not grounded? So I hooked up a dedicated ground wire from the stock ECU chassis to the chassis ground point.

BINGO - AFR 15/1 on both banks w/ CIPHER. Idle normal. Smoke and fumes initially still there but dissipated quickly.

Unbelieveable that chassis ground could make that kind of difference. You'd think that there are multiple ground signals coming over the wiring through the harness.

LESSON LEARNED!

 

Nice!

 

Thanks for the quick responses guys.

KP, your pics and posts about getting the UTEC to fit in a G were very helpful. I decided I didn't want to cut the UTEC housing at all, nor did I want to cut the stock bracket (I always like the ability to return to stock), so I mounted it like you did with all the ports up, but without the bracket (using long wire ties). The ports had to go up to avoid interfering with the glove box. I'm not sure yet if the bottom black trim piece (that you can't really see but protects the blower and stock ECU) will fit back because the ECU connector is still sitting slightly lower than before (I don't see any way to shove the thing any higher). I used a small piece of sheet metal to "replace" the slot that that piece used to be supported by in the right rear corner by the stock ECU bracket. Will have to wait till everything is installed to see if it'll go back on...

 

Glad the pictures helped you out. I tried mounting that thing at least 4 different ways before finding a way that would work. There simply isn't enough room for it behind the glove box.

 

can you elaborate on this mod.

I have some idling issue with my G, and I get different A;F vlaues from each bank, too.

Pics would be great!!!!

 

Can you take picture of how you grounded your Utec? Thanks!

 

I figured out my idling issue.....it had nothing to do with the UTEC. My MAF is very sensitive to the curved section of pipe ahead of it.......

 

There is still a problem with my UTEC (but my stock ECU works fine now).

A new one is in the mail - very impressed with TurboXS customer service. Rather than try to troubleshoot and foul my plugs, they recommended just swapping units.

I was told that the extra ground is not really necessary except under load. When idling it should have no trouble driving the injectors. SO new unit is on its way with a return tag for returning the faulty unit (thanks Mark)...

 

Great customer service! Hopefully it is the unit itself.

 

Electrical problems are very commonly ground-related.

Great detective work.


I did think of that, but in reality, "stuck open" injector is VERY rare.

 

A mechanically stuck open injector may be rare, but if the UTEC was shipped with a bad fuel injector output it would be very possible for the injector to have power at all times.

 

Yipppi. It works. I got the new unit from TurboXS the NEXT DAY! (Called with issue Thurs am, got unit Friday pm).

Plugged it in (all properly grounded of course). And no issue with fuel vapors. Cipher reads around 15 AFR both banks. What a relief. Now I can move on...

I have no idea what was wrong w/ my 1st UTEC unit but I think I had two problems going on. One problem was not having the stock ECU grounded properly whilst the UTEC was disconnected. Second problem was the UTEC driving one bank of injectors full open at idle EVEN though it was grounded.

Both problems resulted in the driver's bank of injectors running max open.

I'm happy I can start my car now without having to take a shower from all the fuel vapors!!!

 

I have a UTEC in a G35 sedan. No chasis ground at first, mounted the UTEC and ECU assembly with heavy duty zip ties. After a few weeks I got P0603 ECM memory failure and P1444 EVAP. Reset and they came back quickly. Thought about it a bit and decided to ground the ECU case, just ran a wire from a bolt on the ECU case to the same ground spot for the UTEC black wire. Its been a few days and many trips and no codes yet.

 

Good call. The shop that recently installed my UTEC, grounded it to the underside of the dashboard panel mount by wrapping the bare wire around the mount. ... So I crimped a connector to the end of the wire and relocated the ground to the chassis (per TurboXS, Great customer service). I also ran a dedicated ground from the ECU to the same chassis grounding point, here:

 

Mardi! Didn't know you upgraded your ecu already! You self tuning it?