Okay.... heres the info you might need to make an assumtion as to what the problem is.
1990 S13 240SX
Redtop SR20DET
Blitz FMIC
Greddy Hotpipe
Greddy Type S BOV
Blitz Downpipe
S13 Blacktop ECU (code E5)

Motor is in, but she runs like shit to be honest with you. It wont rev up and hold....it bucks and tries to die out unless i keep my foot on the throttle, and at half throttle, it feels like youre barely touching the pedal. I checked the MAFS, and unplugged it. Then it will idle, but wont revv past 2grand. That tells me a bad MAFS. Well, i replaced it twice, and still no change. Im using the KA SOHC MAFS...the wiring harness has been converted to run that MAFS.
I checked the voltage on the TPS and it was perfect.
The timing is set at 15 degrees, and lined up perfectly.
The Intercooler piping has no leak...ive checked a thousand times.
The Fuel pump has been checked twice, and it sends pressure to the rail.
The fuel filter is brand new, and works fine.
I have brand new Denso plugs...so thats not it.
The ignitor chip is plugged in, but i dont know how to check the voltage on it. Besides, if it didnt work, the car wouldnt even start right?
The injectors and coils must work...cuz its not missing at idle.
Im really confused as to what this could be. Im totally lost. To make matters worse, im in NJ not in VA. So i cant beg Greaser to come over and work his magic! ( Hi greaser) Anyway, please ponder this for a few moments before you decide its too much of a headache to reply! I cant figure it out, and im in the middle of nowhere here, so i have noone here that doesnt have a motor under 5 liters! When i try to ask a question they all look at me like im crazy when i tell them its NOT carbeurated before they ask. I dont even think they know what Nissan is around here! So please help! Thanks for the time fellas.

 

from srswap.com

"Cranks, has spark & fuel - either just cranks, or catches but won’t run -
Check Timing, Crank Angle Sensor could be misaligned. Engine could be flooded,
check spark plug for raw fuel.




Runs OK, but no power -
Check timing, set to 15 degrees, 2nd mark from the right on crank pulley.




Drivable but can’t boost above certain psi, or can't give more than 25% throttle without bucking -
Leak in intercooler piping under boost, even a small leak will make the car sputter
and buck with any significant throttle. MAFS or MAFS wiring problem.




Idles OK, but can’t rev past 2500 rpm -
MAFS or MAFS wiring problem."


sounds like you fucked up you MAFS wiring if you've tried different mafs w/ the same outcome.. did you use shielded wire for the sensor or just some regular wire you had layin around?

 

Ill triple check the MAFS wiring, but im almost positive its not that. Ive checked it to the grommet. Ive checked for boost leaks time and time again...idunno. Three wires to the MAFS right? White, Black, Black/white stripe. Its in there right...the plug is in perfect shape. theres no harm in triple checking it. Thanks NISMO.

 

is your ecu plugged in all the way? bolt tightened down, in there flat, etc? that might fuck something up

 

If not electrical...It definately sounds like some boost leaks but what do I know. I pay someone to work on my car.

 

Is your BOV leaking?

 

Yeah the ECU is tightened...Ill double check the IC pipng for leaks though. Cant hurt to try it again

 

just because your ignition mod. is plugged in, doesnt mean its not the problem.. i had the same problem with my 5.0, would idle fine, around 1800-2000 would start missing once it was heated up.. and, not to make me or you sound stupid, but double check your plug wires to the distrib. (it does have 1 right, no COP..? lol)

 

When it won't go past 2K it means its in safe mode. Its supposed to do that when the MAFS is disconnected or it means the MAFS is broken/incorrectly wired.

Things to check (assuming the MAFS is good):

1. Make sure the EGR valve isn't sticking.
2. Disconnect each injector harness 1 at a time. When you do that the engine speed should drop, if not make sure you can hear each injector clicking.
3. Check to make sure each spark plug is working and not fouled.
4. Check fuel pressure.
5. Check O2 sensor.
6. Pinch the blow-by hose, if engine speed rises you have an intake leak.
7. Disconnect TPS. You should be able to set the idle ~750, if not the idle valve might be dirty or bad.
8. Do a compression test.
9. Make sure the ECU and harnesses are plugged in all the way.
10. Try using another ECU.

 

I found the problem.....it was three..count em... THREE bad MAFS'. I bought a new one, and plugged it up, and she runs perfect. Thank you for all of the info, and guidance. Ill tell you... i felt pretty stupid that i couldnt figure it out. By the way...anyone have a T25 for sale? Thanks again everyone.