Fuel or Ignition Cut, PLEASE help.

[Kansei240sx]

Hey guys, i've been on this site for many many years and i have posted here in the RB section, which i consider my home in quite some time.

Anyways, heres the skinny. A customer of mine has an RB25DET S1 in an S13 i did all of the wiring, installs and such, and i am very thorough in my installs and have done SEVERAL RB26/25/20/SR/VG swaps into a S chassis cars.

Heres my deal, i have yet to run into this problem specifically in an RB after doing these mods, I've had ignition cut problems but not this bad.
Here are the mods this thing has, and things i've done.
SAFC-1 (I absolutely hate these things, but the kid does not have the money for (Nistune/AEM EMS/PFC) any of which i prefer to use.
Z32 MAF, Triple checked wiring with settings IN 2 OUT 5, tried in 2 and out 4 but the problem does not change.
AVC-R - 10psi-ish
STOCK TURBO
Greddy Intake Plenum
Q45 throttle body
15 degrees + or- 1 degree on timing
HKS Green filter
FMIC
s*** HKS Knockoff bov.
Full 3" exhaust, no cats, no resonator with AM performance downpipe recirculated
AEM Fpr set to 43 psi static
NO boost leaks, i have a gauge set up just outside the turbo outlet, and on the very back of the intake manifold and the pressure difference is almost negligible.
It has NGK Coppers heat range 7 gapped to 0.8mms.

I've followed the instructions of another guy here
rb25det-sputtering-problem-solved-t410370.html
I was having a hard misfire at 4500 rpms to 5000, i performed everything in this step and now i can go up to about 6200 rpms without any problems, but the car just seems to hit this ignition problem again. This whole time i am saying to myself, well obviously if i have been doing all this and it is slowly getting better and better than it probably just needs a set of coil packs or an ignitor.

So i did some data logging and then i start to second guess myself. You'll see why.

The last value in this table is the mass air flow sensor, I've grounded and re-grounded this thing ( both wires in the same spot, together, apart, etc,) with no change.
For this car to be using an N62 Maf why is the voltage reading going so high? I figured if anything the reason i was hitting this hesistation is because it was hitting some sort of fuel cut because it is no longer seeing metered air.
The boost SLOWLY creeps up maybe half a pound or so through the RPM range once in full boost which is about 10-11 in this pull. It does not matter what boost setting i am at, whether it be 7psi or 13 psi.
No matter what i have done, the MAF readings almost always peak out, and the higher it gets the more it misfires.

The only thing i have not swapped out yet is the Ignitor, has anyone else ran into this problem before? If i swap the ignitor and it runs fine, aren't those really high MAF values?

I feel like i am over looking something this car is driving me nuts and working 18 hour days for the past 2 weeks solid is making me frustrate myself really quick. Need help brothers!

[Kansei240sx]

Bump, anyone have any ideas? Im going to swap ignitors tonight and see if that changes anything.

[RustspecS13]

I had a miss fire problem that was really weird. I never really did hardcore diagnosing, and I tried to buy a maf just to try and have for a spare.

It was a strange problem, if you were smoother with the gas and used the smallest amount possible you could run it to redline. If you weren't smooth and just went wot, it would hit something like a revlimiter between 3500-6000. But it got ok mpg and drove ok if you were smooth.

I had bought a Z32 ignitor and pigtail since no junkyard around here had a j30 or would sell me that separately. I replaced the OE ignitor before I ever drove it and that ended up going bad and causing the problem. I picked up another one and it returned to normal.

If it is an ignition problem, I could see when it missfires/hits redline the inconsistent airflow causing strange maf readings.

If its a fuel issue, or just to cover your bases, maybe you should pull the fuel pump assembly and check the hoses and make sure they aren't leaking in the tank.

~Alex

[Krazykouki]

Have you tried initializing the SAFC?

Try that and make sure all the throttle settings are 0 and everything else is oem settings for the SAFC except for the MAF.

Set it up for the MAF , 2 in 5 out and then 1 and 1. Make sure it is also setup for 6 cylinder. After that, see what it does. See if the engine is getting any knock as well...I wish you at least had an SAFC 2.


edit: My car was doing the same thing, the Z32 MAF was maxing out, I had no idea why..even bought another MAF thinking is was bad..turned out to be the SAFC itself. I initialized it and redid my settings exactly like I stated and it works fine now...still not sure what was going on with it and haven't had a problem since.

[Kansei240sx]

Yeah, at least if it was a 2 i'd see knock.

I tried another completely different set of coil packs, and a z32 ignitor, and another RB25 ignitor and the problem still persists.

I have a friend bringing another MAF tonight so i will see what happens then. The more i diagnose this thing the more it is starting to point towards maf.

[Kansei240sx]

I GOT another Z32 maf and the car pulls great. The MAF element must've been faulty or had a bad circuit causing increased or less resistance than normal causing maf readings to peak out. Thanks for the replies.