Alright so I just got my car up and running after rebuilding it myself. Car in question is a 1990 NA with a streetported JDM s5 turbo swap, running with rtek 1.7, OEM primaries and 1000cc RC secondaries and aeromotive 380 lph pump, trailing spark plugs all around with 10mm magnecor wires, v mount intercooler, battery relocation to the storage bin, emissions deleted (including the bac since it was destroyed), omp delete running 100:1 premix, and n350 AFM since the turbo AFM was missing from my engine when I got it. Most of the issues have been sorted out but I'm still having trouble with cold starts and an absolutely excessive rich condition. Can only cold start after having the battery charged up, with a jumper box and freshly cleaned or changed plugs since they're getting fouled quickly. The cold starts are killing my battery but I think I may also have some extra electrical draw while the car is on but not running. As far as running super rich I know that the n350 AFM will make it run a little rich but this is way too rich for just the AFM to be an issue, would a new bac help? Could I also have leaky primary injectors since they're most likely original to the engine (any recommendations on how to test without spilling fuel everywhere)? Hot starts have been fine and other than it being super rich the car runs and drives great so far while breaking in the engine with the waste gate flapper disconnected. Thanks in advance for any helpful insights.

 

The BAC is used on starting the car (goes full open to add some extra air), so that might help some, but could also not be your only issue.

 

No FPR? bigger fuel pump can cause this problem.

 

I was kinda leaning towards the possibility of it being multiple issues. I can't recall if the BAC is the same across models but that's a simple search away, if so i should have a spare floating around somewhere. Anything else I should take a look at while I'm at it?

 

Unfortunately still using the stock s5 turbo rails was hoping to find a set of the rising rpm rails by the time I got it all together. Might try to find an s4 secondary rail or pair to run an adjustable FPR in the meantime. Fuel pressure seems pretty well within spec otherwise according to my inline gauge.

 

What do you believe to be your fuel pressure?

 

It's a hair over 30 psi at idle and about 35-36 psi while not running with the stock s5 turbo fpr

 

is this an N350 afm with an N370 ECU? if so, why do you think it would NOT run super rich with the weak springed AFM on a turbo engine with larger injectors? add in the fuel pump raising pressure with the stock FPR and you have 2 reasons for it to be spitting raw fuel out the tailpipe, compound this with an engine still trying to build compression and well, you get the idea.

 

Yup n350 AFM on an n374 ecu. I did expect it would run pretty rich just not quite this bad. Was only running the n350 as a temporary fix until I could get the proper one, which is now bumped to the top priority on my parts list along with fuel rails and an fpr. Looks like I'm back to hunting down some parts will post up results once I take care of those issues.

 

you can lean out the idle by popping the plug off the air bleed screw on the AFM and turning that screw out a few turns. this isn't a recommended procedure but hell with it.

 

I'll give that a go after work see if it helps with starting at least for now. I'll be sure to keep a note of how much it's adjusted in case things don't pan out