3v swap troubleshoot

[Bodvar]

I just swapped a new 3v into my 05. The old one didn't have any major modifications and it just has a Borla exhaust, Bama tuner, and cold air. You're basic stuff to get you the 200 extra hp you want... Anyway, I got the swap done and everything seems to be in order. The engine is running lean though and when the tune is put back in stock, it starts and dies. In a 93 octane tune, it runs and drives but it stutters like it's lean. I checked the engine light and it does confirm that it's lean. This light isn't on all the time even when it stutters. Everything like the injectors seems to be working properly, they did operate perfectly before the swap, and I changed my gaskets out. My experience on anything newer than a foxbody is extremely limited and I'm looking for any ideas.

 

[Dman64]

Is there anyway to log your fuel or see what you O2 sensors are reporting? Any idea what your AFR or Lambda is with the 93 tune? What are you running for a fuel system?

D

 

[Juice]

Put the stock airbox in with the stock tune. I suspect your CAI is a "tune required" one.

 

[Bodvar]

Put the stock airbox in with the stock tune. I suspect your CAI is a "tune required" one.

I've run it in stock with the CAI it has in it now before. Even then it still sputters down the road with the tune I've had on it.

 

[Juice]

Any pending codes? Fuel pressure ok? Clogged fuel filter? How fresh is the fuel?

 

[Bodvar]

Is there anyway to log your fuel or see what you O2 sensors are reporting? Any idea what your AFR or Lambda is with the 93 tune? What are you running for a fuel system?

D

I can try to find those numbers on my Bama tuner. In moments like these I really just want an old carb

 

[Bodvar]

Any pending codes? Fuel pressure ok? Clogged fuel filter? How fresh is the fuel?

Code just shows lean in bank 1, which just confirmed for me that it's lean. Put in a new filter because I had the same thought. Fuel pressure is also good and the fuel was about 2 months old but I put 10 fresh gallons in yesterday.

 

[Juice]

In that case, if it is just one bank lean and not both, it maybe an upstream O2 sensor issue on the lean side.

 

[Bodvar]

Drove it around now I get a rich on bank 2 code.

 

[Juice]

Do you have a way of viewing live pcm data? If not, you could swap the two upstream o2 sensors. If the code moves with the sensor, you have a bad o2.

 

[Bodvar]

Do you have a way of viewing live pcm data? If not, you could swap the two upstream o2 sensors. If the code moves with the sensor, you have a bad o2.

but how would that help if now I'm getting codes from both those sensors?

 

[Juice]

but how would that help if now I'm getting codes from both those sensors?

You said only bank 2 was lean. Thats why I suggested swapping sensors.

 

[Bodvar]

You said only bank 2 was lean. Thats why I suggested swapping sensors.

No sorry for the confusion. Bank 1 was showing a lean code. Now bank 2 is showing a rich code

 

[Juice]

No sorry for the confusion. Bank 1 was showing a lean code. Now bank 2 is showing a rich code

That is really strange. O2 sensors wires swapped by accident?

 

[Bodvar]

That is really strange. O2 sensors wires swapped by accident?

No it's all in where it goes. I had the thought that this new engine has parts that are upgrades like a new set of cams.

 

[Juice]

One side rich and the other lean. I dont think that internal engine mods would have that effect.
You can always do the basics, pull plugs and do compression check. If any one plug looks different than the others, you have it narrowed down to which cylinder isnt happy.

 

[MrBhp]

Was it a full long block with all accessories swap? Or did you use the original intake?

 

[Bodvar]

Was it a full long block with all accessories swap? Or did you use the original intake?

Full long block with accessory and intake swap

 

[MrBhp]

I'm sure it's obvious why I asked. Those issues you're having can be caused by a bad intake to head seal. Yeah, as stated before, read the plugs. That will tell if you have an actual lean condition of if you have a sensor issue, or both. If the car is running poorly as you state you're probably going to find some sign of the plugs, which really won't tell you the problem, because the computer is trying to compensate for erroneous data. BUT, it's a start if you have a particular hole that's dry. Could be a bad or clogged injector. That would be awesome if it was that easy.

 

[Bodvar]

I'm sure it's obvious why I asked. Those issues you're having can be caused by a bad intake to head seal. Yeah, as stated before, read the plugs. That will tell if you have an actual lean condition of if you have a sensor issue, or both. If the car is running poorly as you state you're probably going to find some sign of the plugs, which really won't tell you the problem, because the computer is trying to compensate for erroneous data. BUT, it's a start if you have a particular hole that's dry. Could be a bad or clogged injector. That would be awesome if it was that easy.

I made plans to go over my plugs again when I get home from work. I'll also look for a vacuum leak and a bad intake gasket. The gasket is new so I don't expect that.