SR20 running rich, have ideas, seeking advice

[1320VR4]

So my SR20 has been running rich since I got it. I bought a proper wiring harness so my alternator charged at the correct voltage and it's been running signifcantly better however still not perfect yet.


1. I'm running an open atmosphere bov setup, would setting it up to recirc help tremendously? Most of the photos I see of SR swapped engine bays have people running open atmosphere blow off valves with stock draw-thru mafs.

2. The pcv port on my valve cover is connected to the stock oil catch can on one side and is completely open on the other side. I would assume this could be a vacuum leak which should make it leaner, but I'm not sure if this is required to be hooked up to anything.

3. I'm running a Walbro 255 with a stock FPR, could it be overrunning the FPR? I know in the 3000gt world this has happened before quite a few times.

I'm pretty sure there are no intake leaks, I checked it before and it was sealed good but that was a month+ ago too.

Any other suggestions on things to check?

[steve shadows]

Check your fuel pressure. Should be 38-40 PSI max at idle with vacuum connected. I would also check your injector o-rings. You can pull the rail off fairly easily on the S13 SR motors and turn the key in on and put some paper towel in front of the injector pintle caps and see if any of them are leaking on the lower o-ring that seats the injectors into the side-feed rail as well. Good starting points. Also MAF voltage and condition of maf could effect this as well as vacuum leaks. Good luck!

[1320VR4]

Originally Posted by steve shadows

Check your fuel pressure. Should be 38-40 PSI max at idle with vacuum connected. I would also check your injector o-rings. You can pull the rail off fairly easily on the S13 SR motors and turn the key in on and put some paper towel in front of the injector pintle caps and see if any of them are leaking on the lower o-ring that seats the injectors into the side-feed rail as well. Good starting points. Also MAF voltage and condition of maf could effect this as well as vacuum leaks. Good luck!

thanks! First nice day we have I'll go through this mini checklist. IIRC I last checked the fuel pressure after the SR swap and it was on spot. It could have been with the KA though, I really can't remember lifes timeline lol

[1nasty240sx]

You should check for boost leaks, get an aftermarket fuel pressure regulator with a guage so you can see what psi your car is running at and if you can re route your bov to recirculate should all help out with your problem. Also sr's run rich from the factory so if you could get a tune that will also help once you get everything figured out first of course.

[Dro]

A vacuum leak would not cause a rich condition, however a boost leak will.
Recirculating your BOV would only affect your A/F for the time that the BOV is open.
I run a walboro-255 in my car on a stock FPR with stock injectors, I haven't heard of any situations where the walboro is too much for it. Check your fuel pressure anyways!
If you have a Digital Multimeter you should check the resistance of your injectors, specifications can be found in the FSM which is conveniently on nicoclub.
Remember a clogged air filter can cause a rich condition as well!

Do you know exactly how rich it is running, or are you assuming based on how the car runs?

[1320VR4]

It's got a new air filter.

I don't know exactly how rich it is, I have to save some funds to throw in a wideband. Just bought some pricey parts for my VR-4 so I'm low on those funds at the moment. lol

It runs rich enough that there is soot on the back bumper. I know for fact that after boosting and getting on the next gear it soots a little bit, which should be from the open bov. As for the rest of the throttle curve, I'm not sure, and of course I'll need that gauge to figure out exactly where it's at.

[Fre3_World313]

So I do believe my sr is running rich due to the dirty ass A’PEXi filter.

Has anyone else had this issue

I’m fouling plugs in like 10 minutes

Any ideas.

I have a new filter and I’m gonna try that