Greddy AFPR?
 

I had mines installed like the picture on top and then I switched it to the one on the bottom. Now that I did this my car has some mean ass back pressure or back fire. It sounds like a shot gun or a pop when I shift. Any Ideas what happen when I did the switch?

running rich as fuck?

How do I fix this problem.

Without knowing anything else about your car, it will be impossible to tell what's happening. Backfires are a result of unburned fuel entering the exhaust stream and somehow finding oxygen. It sould be as simple as an exhaust leak.

Like any good forum user, you should put a list of modifications in your signature so people don't have to ask you every time you post what your setup is. Is it a stock Greddy kit? Are you running any sort of ECU? BOV? IC? INJECTORS? FUEL PUMP? Stuff like that we have to know to help diagnose your problems.

You could also put your location in your profile... maybe somebody local is a pro and can just come over to your house and help out.

This problem only started when I switch the lines on the AFPR around, it was running fine before I did the switch.

lmao, then umm, why did you switch them?
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Cause I told him to, because it was plumbed incorrectly at first.

Just came back from checking all the lines, no fuel leak or vacum leak, no exhaust leak, I know its gotta be something with the fuel, it smells really strong in my garage.

is your factory FPR still in place? i cant tell from the pics...

yes it is

Before the switch the FMU was not working at all free flowing, it looks like the stock FPR was doing all the work. Now that the FMU is installed in the right position it is taking the fuel pressure up to what ever the pump can put out (MAX Pressure), causing a super rich condition. if prolong driving in this condition presist your cat will be hollwed out within 20k miles. Here is a quick test after a nice hard drive in boost. Then Park the car while still idleing and look or temp gauge the cat. If it is glowing red or above 900F then it is seriously being over worked. caused of this is a super rich condition. can you read you A/F ratio? i bet it is in the 9.0-10.0 range all the time. what ratio is the vortex regulator 12 to 1, 6 to 1 ? and is that the only thing that makes this kit work (run it super rich during boost)? what about timing (MSD timing retard)? more questions thet answers, but hard to give answer with so many missing veriables.

are you sure the noise you are hearing isn't just the bov?

I have not touched the Vortec setting, I was told you have to open it up and add new disc and stuff, as for timing it was changed to 10 degrees like greddy wanted. Still trying to work out the bugs, and no its not the BOV that is making that Boom noise.

Actually GReddy suggests retarding the timing back 4° to 6° IIRC, 10° is how it's set from the factory.

The FMU is hooked up correctly now, if you're backfiring it's too rich, and I'm unsure as to why. The GReddy kit is pretty darn basic, and not much to it but a turbo and a FMU.

Have you touched the AFM, injectors or fuel pump?