man i've searched and searched this forum and still need help! i just finished an s5 to jdm s5 turbo II swap. i have corksport dp, na maf, stock everything on the engine and a knightsports n374 ecu. i also have an n370 but that only runs the engine on one rotor. the knightsports ecu will run both rotors and it starts up on a dime. the only issue is it wouldn't go past 0lbs before it started cutting out and sputtering. can't go wot or it hits boost and cuts. i swapped out my omp and now it kinds hits around 1 or 2 lbs before it cuts and sputters. any help would be awesome!

 

why NA MAF??
it has hit max flow and is sending full signal to the ecu..
which is thinking now load is MUCH higher than it actually is
.. and is sticking in far more fuel at this point than it should !

capiche?

 

Are you still running the stock NA boost sensor as well as MAF
What injectors do you have in and what is the knight sports tuned for?
Might wanna find that out before you blow your engine eh?

 

from what i've read on the forum swapping out the maf isn't a necessity. i suppose this could be wrong??

i'm running the n370 boost sensor. stock injectors and no clue what the tune is for. can i go to any tune shop to have them check it?

 

cant fathom why anyone would tell you the NA MAF will work.. its pretty easy to see what will happen
.. and if that is someones idea of tuning by modifying the MAF range then run far away ..


you will require the correct MAF

..//
there is a HUGE hint in there for those trying to work out the n370 V n374 bug...
you is using the NA loom ??

my theory is there is a pin out change between JDM and NA looms
that has one setup with the wires that come along the ems loom as primary and secondary for rotor 2

on the other loom instead these same wires from the ems loom are config as secondaries ( or primaries )

have seen this once before where i just re-arranged the plugs on the injectors and it all ran.. and yes an ex NA car.. with a JDM turbo conversion .. cant recall which ECU it was

 

i understand the car will run slightly better with the correct maf but that shouldn't cause me to not make more than 1lb of boost and can't go wot, could it?

 

yes it would.. max flow is reached in the AFM . full signal is given at around 600 cubic metres of air per hour

so the N374 ecu.. which expects full signal to mean that is actually 720 + cubic metres of air per hour
,, then sticks in the right fuel to keep 720 cubic metres worth of air wet per hour

but you have 600 cubic metres per hour of air.. which would then i expect be intensely rich.. intensely rich blows out spark and thus works like a boost cut


PS
an EOMP ( or ecu driver for it ) fail will be doing the same thing
.. EXCEPT it will have a 5 minute period where it boosts just fine,, before the limp kicks in ..
typically with that fault you coast down,, turn off and restart,, and have 5 mins more fun

 

awesome so i should get boost once i switch it out? any way to test it before going off to source a new maf?

 

afm*

 

MAF/ AFM // same thing just one is english , other american
.. yes i expect so .. far too rich is a better reason than most
cant see it being EOMP due to permanent nature of the fault

 

Do you know what the KS ecu is setup for? Injectors or otherwise? Do you know what the engine has for injectors? Pri & sec?

FYI, I ran my 87 TII on a NA AFM for a year or two before I realized I was maxing it out, but it ran fine on a RTEK.

 

I have no idea what the tune is set up for. i ordered it online and it didn't come with a spec sheet or map.

That's what i have been reading on the forum but i suppose it could be possible that the ecu has been tuned specificly for the n374/370 ...

 

1987 uses the flap door AFM
.. looking at the units i see the difference between turbo and NA AFM being the resistance to airflow offered by the clock spring tension
.. its not hard to click the spring a few times and re-range a unit with no one being any wiser

but a 1989 N350/N370 MAF differences are more marked
.. the shape profile of the MAF internal plug is different
.. its not a factor that can be adjusted .. and nor is it an Rtek ecu
( which possibly may even be altered to be MAP sensor based load input// who knows ?? )

OP.... cant move forward till rules out the wrong AFM as an issue
.. do most obvious suck see first,, and this is most obvious

 

PS.. the next issue ( secondary staging / earth issue ) [which AFAIK is only for the s4 cars ]
is related with signal/ shield and injector earths all having a ground loop or earth potential issue

the fix for that is to unrap the loom about 50 cm up from ECU plug and resolder
( and add an earth strap ) to the brass crimps that have all these earths bundled together

 

well i'm gonna try and source a afm and see if that bitch does the trick. i'll let you guys know if it works but in the mean time anymore ideas would be great

 

Updated. Got an n370 afm and it still does the same thing. No dice fellas. Doubtful but I'm gonna check for vacuum leaks then start checking the injectors. Car smells like its running mad rich and fuel economy is ****. Hopefully if we can sol e this it'll help other people w this problem

 

OK.. what are you running for fuel pump and reg.. have you verified what the rail pressures are?

 

fuel pump is a walbro 255 and it's on the stock fpr. i have yet to take it to my mechanic to do any other checks

 

That knightsport ecu might be tuned to run different injectors setting.
If you are on the stock 550cc injectors and the KS ecu is setup for something higher, the car will bog and stutter and spark cut out from too much fuel.

Get another 370 ecu and see if it works. You have too many variables to figure out the problem, but you seem to have a fuel problem. Check to see if all you injectors are working also.

You can also be running very lean because the fuel pump is not supplying enough fuel because it is worn

 

^This. That KS ecu is really messing with troubleshooting. What engine wire harness are you using? Your best bet is using the matching harness and ECU. Even then, using N374 stuff seems hit or miss.

Regarding shops: Very few places are going to be capable AND willing to troubleshoot your setup. Look for a recommendation in you regional forum and has a history of doing rotary JDM swaps. I've found shops will lie about their experience or go completely cross-eyed when I mention it's an RX7.

 

firstly-- if the KS is set up for larger injectors.. it will LEAN out when installed with smaller injectors

now.. you have walbro .. and particularly if your car was previously NA
... then the problem lays in that the walbro can flow too much for the reg at low engine engine demand.. the NA car lacks a hi/low voltage controller for the fuel pump// and thus may have excessive rail pressures under certain conditions

this may even be the reason the vehicle tries to flood on the other ecu.. but may be OK ( up to a point ) on an ecu tuned for larger injectors
.. but not from the point where rail pressure equalizes to normal because engine demand is higher and the reg no longer too restrictive

you need to tee a pressure gauge into the fuel delivery hose and get some indication what pressures are doing and when

this is also to check to see if PRCv solenoid operation is working
.. as if denying the reg a boost signal.. would also make for the issue you see

 

just thought i'd like to add that in city my mpg is rediculously low but on the highway it's amazing. like i can drive 20 min and the needle wont move. in the streets that bitch will drop a quarter tank in about a mile or 2.

 

There's no way you can lose a 1/4 tank in 2 miles unless you're leaking fuel , that or likely exagerrating the amount of fuel you go through.

If what you said were correct you're getting half a mile to the gallon, which I don't see how that could even be theoretically possible unless you were drag racing.

 

This makes no sense whatsoever.

 

i was trying to get a more accurate number today but remembered my speed sensor is broke so no trip. I may be off but it is quite terrible in city. more so than i believe it should be.