Bank 1 Rich Bank 2 Is Perfect

[Max22]

So I'm getting my car tuned and for some reason I have one bank that runs rich. I just put in a used set of injectors and I've flipped the banks from one side to the other. Put in new plugs, flipped the coil packs, tested the MAF and it all did nothing and I'm stuck. Haven't done any compression tests but I don't think it's a valve issue.

Car runs great, no backfires or codes or anything but the widebands he put in to monitor the F:A ratios says bank one is rich. Don't remember the exact numbers but we're talking like over a point difference from one bank to the other...

Anyone have any clues?

Also this is a full PI swapped engine into my 96 gt but I don't think that's relavent.

 

[Max22]

Oh and I forgot to mention I did an egr delete but this is information my tuner is aware of.

 

[Max22]

Update: did a compression test on bank one and all came out at about 175psi. Also did a leak down test and it came out clean. At this point I'm thinking I could be off a tooth in my timing on one side. That and fixing an exhaust leak post o2 sensor is about all I can think of...

 

[Max22]

Update 2: compression tested bank 2 and all tested even with bank 1 ~175psi. Also verified timing and it was all lined up correctly. Next thought is checking fuel trims, maybe doing some tests on the injectors, possibly putting stock tune and injectors back in, then I might mess with some exhaust clamps to see what effects it will have on the widebands.

 

[NerdKrusher]

I'm sad to see no one has offered any advice.

My at has a similar issue. It's actually a 96 with a pi swap as well. (What a coincidence)
I recently bought a bama x4 tuner for my car. It has a built in af ratio gauge. I noticed on it that occasionally the right bank will run rich for a bit. Then it will go back to normal. If I rev the motor while it does this, then it puts it back to normal as well.

I believe what this is is a dirty fuel system. My motor has 100k miles on it now. But my car has 200k. Fuel lines, filter, pump, injectors. These things gum up and get dirty over time and heavy use.

Try using a fuel system cleaner. Personally I'd go with a bottle of the B12 chemtool. Put that in the tank, give your motor the "Italian tune up" and let that stuff do its job. It cost $3 a bottle. Not a big risk if it doesn't fix your issue.

After the chemtool, I'd star using marvel mystery oil in your tank. I use it in my stang and I can promise you. That stuff is amazing. Best of luck bro.

 

[NXcoupe]

Usually this is caused by cam timing being off a tooth or so. Now, with that being said, mhs wrote a lot about how far off the factory stamped cam gears are. Not enough to cause that variation, but the widebands could be either going bad or need calibrated. Do the plugs look the same bank to bank, as far as color? If so, don't worry about it. I've never see anyone install dual widebands in a car for tuning. How are you reading these sensors.

 

[NerdKrusher]

Usually this is caused by cam timing being off a tooth or so. Now, with that being said, mhs wrote a lot about how far off the factory stamped cam gears are. Not enough to cause that variation, but the widebands could be either going bad or need calibrated. Do the plugs look the same bank to bank, as far as color? If so, don't worry about it. I've never see anyone install dual widebands in a car for tuning. How are you reading these sensors.

Isn't the 4.6 very sensitive to cam positioning? I remember from the information video from Ford about the engine. They say if the cam isn't lined up perfectly on installation, then the intake and exhaust valves will hit the Piston.

 

[NXcoupe]

Isn't the 4.6 very sensitive to cam positioning? I remember from the information video from Ford about the engine. They say if the cam isn't lined up perfectly on installation, then the intake and exhaust valves will hit the Piston.

No. I've seen as much as 2 teeth off and no valve to piston contact.