Dumb question I know does it feed on the drivers side and return on the passenger side if looking at the front of the car...
i have a really strange fueling issue I believe can only be a couple issues bad fpr or clogged return line my car after being 3 weeks ish or so has just started running pig rich out of know where like moss fire aem pegging at like 9ish and miss firing..

this just started this afternoon car has built head cams Wally 255 ets intake pipes and core speed density tune on tuned with aem methanol kit the meth kit is shut off just to make sure that was not leaking and causing it...

starting it it cold it hold 14.7 perfect for like 25 sec then goes rich to about low 12s any blip of the throttle goes really rich misfire rich any input ??

 

Now I’m stumped woke up this morning for work fired the car up and it drove just fine did 2/3 second gear pulls and no problem I hate when I don’t get a cel or I can’t repeat the problem so I can fix it

 

So what is your question? It sounded like perhaps your front O2 was on its last legs but itll typically throw a code for that. Do you think you mixed up the feed and return line, Im confused...I doubt you swapped them as if they are factory lines the feed is kinda a unique setup how it ties into the rail with 2x M6 bolts and a o ring vs the return which is just a line and a spring clamp.

 

The factory stuff will only install one way. You can't mess it up.

 

No I believe there is a clog in the return line sorry if I didn’t clarify that it’s not an o2 the car is tuned for full time open loop on speed density or the FPR is crapping out if there’s a clog in the return it will cause major rich conditions when trying to get on it because your fuel pressure spikes at the rail...

so so I just want to make sure which one was the return line so I could pull it and run air through it to see if it is clogged if it’s not then I know to start looking at my FPR also meant to say the car was professionally tuned by English racing about 3 weeks ago it’s not a tuning issue

 

So I blew the return line out it’s clean to the tank but still have the same issue what could change overnight to cause my car to peg rich and fall on its face when getting in the throttle.
The car was tuned 3ish weeks ago on speed density and had no issues what so ever the fuel pump primes and is good obviously because it’s dumping crap tons of fuel under any boost..
since the car is speed density there’s no maf so my only other thought is bad FPR or my Omni 4 bar map crapped out does the 4 bar have anything to do with fueling on speed density i don’t even know...
mind you the car idles fine it sweeps a little back and fourth it’s even fine when not moving and blipping the throttle it’s only when it starts to build boost...

at at this point I’m lost I mean it dumps enough fuel for the car to bog down. And try to stall so my next step is get a fuel pressure gauge splice it in and see what I get and order a new map sensor anyone else have any input

also the car does not use a AIT sensor English racing tunes all there SD cars with the fuel temp sensor also no check engine light so that makes it harder to track

 

Swap the map sensor to rule that out that will absolutely have an affect on fueling.

 

yeah I’ve got one on order now the weird thing is when it’s cold outside the problem is gone not like when the engine is cold just cold out side in general as the day goes on and it get warmer it start plus it it stumbles when it turns over when it warmer outside