SD Suddenly Running Rich(10s-11s) Across the RPM Range

Hey guys,

We're sort of stumped trying to work through this issue. Has anyone experienced an issue with running rich (10.4-11.2 at idle on 93) on a speed density setup. It sort of feels like the reverse of a large MAF intake leak. This is an EJ207 running on SD w/ a rotated setup(2004 USDM WRX). He is running freshly cleaned ID1000s (from T1 w/ flow specs), running a walbro 460(iirc) at 100% w/ relay, Fuel Lab FPR, Radium Fuel rails with dampers. It was previously running fine (~2-3% across the cruise range). He drove it and noticed it acting a little strange with the rich idle. Drove it to work, seemed to be fine. Then on the way home it got substantially worse. No major changes were made on the maps, we've reverted to previous versions to confirm.

Things that we've done:

-Reverted to previously working maps that were solid.

-Pulled the plugs: all appear to be rich, which SHOULD rule out one stuck injector.

-Checked Fuel Pressure. Line Pinched it's at 43.5lbs and 38ish without dropping the vac source.

-Checked O2: it appears to be solid and matching our wideband. We've forced open loop and it still buries itself in the 10s so it doesn't appear to be the o2.

-Map sensor is reading correctly.

-IAT reading correctly or close enough to not throw anything too crazy into the mix

-ECT reading correctly here as well.

-Cam and Crank Pos also seem to be well, we're getting feed back in seeing that they're going into the "on" state when running and off when not running.

At this point we're considering (please correct me if my theory is off):

-Some sort of obstruction or hindrance to the intake/exhaust side which would throw off the air coming in. I'm not even close to sold on this theory but something we've considered.

-All 4 injectors are stuck open (rich on all 4 plugs, 2 seem to be worse than the other 2 but generally pretty rich)

-Plugs are so fouled that it's running this rich from unburnt fuel. This would be extreme, but has anyone seen behavior like this?

-Bad FPR? However if it were bad it wouldn't hold the pressure steadily. One thing to note here is when when we kill the car the pressure drops quickly, moreso than any of the other cars running similar setups we currently have.

-Fuel Pump or filter. Not sure what would jack up the flow here but keep the rail pressure the same but its a consideration. He's running a relay w/ the pump running 100% throughout the range.

Again this worked previously and he had solid fuel trims/delivery. Whatever the issue is it seemed to go out at about 50% then 100% after further driving. At this point it will run and drive but it consistently stays in the 10-11s and never reaches stoich.

Sort of at a loss here. I'm sure it's something small that's broken but a ~20% change at random makes me think mechanical all day long. Anyone had any similar experiences

Has this car always been using MAP sensor or was it recently changed to MAP? Also, what ecu brand are you running?

He's been running SD for a good while. So no sudden changes there. It's a stock ECU unfortunately running the Group N/Carberry Rom. This could very well be a tuning issue but with no major changes in the revisions, I just can't see it now adding 20% more fuel on a whim. Thank you for the reply!

hole in the fuel pressure reg / eg fuel up the vac line .

Awesome suggestion. We'll check it. Thanks!

Issue resolved. Thanks for the guidance fatboy454. Turned out to be 1 of the 2 brand new dampers from Radium had a tear in it. They're overnighting 2 new ones and a tshirt. Great customer service. Great company. Thank you guys!