need help asap please

[lexforlife]

this is my first na-t build and although i have some good guys around me with na-t sc 300 we are all stumped on this one


since pulling motor out and doing everything req to go na-t ( headgasket,oil lines etc etc) and converting over to r154 5sp, we have reinstalled motor car starts up fine , one crank and it running everytime

however its dumping tons of fuel and i mean tons of black smoke

i am using rx7 550 injectors that drop into fuel rail with the square tops so they plug right in.. i bought the na-t kit used with the injectors but i negelcted to have them sent for flow testing or even cleaned


i have since installed the 2 o2 sensors into the down pipe ( this is a 97 sc300 so its OBDII) to try and keep ecu happy although the rear mounted o2 i have yet to put into midpipe

so question is in your guys best opinions why do you think car is dumping so much fuel

could it be leaking or dripping or stuck open injector/s

could it be the last o2 sensor not being installed so ecu does not know what to do

could it be egr valve ( now we have removed all egr related stuff and have installed egr block off plates)

bad pcv valve

i am using map ecu v3 and even when i zero out all tables the injectors still dump fuel , no change in bahavior so i know its something with oem stuffor the injectors themselves


any help with be much appreciated for i really want this car on the road already

thanks guys:)

[DaveH]

With the 550's you'll need to pull a lot of fuel for the car to run good (I'd assume you already knew this), set the mapecu to pull around 60% fuel and see what that does. What is your base fuel pressure at?

[98mkiv]

are the injecotors the same impedance? As stated above, you need to pull fuel out.

[lexforlife]

With the 550's you'll need to pull a lot of fuel for the car to run good (I'd assume you already knew this), set the mapecu to pull around 60% fuel and see what that does. What is your base fuel pressure at?


thanks dave for replting

i need your professional help here


i have pulled all fuel via map ecu and its still dumping


i may have just found out that the injectors supplied to me although drop in and clips to factory clips are actually the ones that req a resistor box

they are the rx7 550 square tops black with tan tops ...i am now being told that i need box for those as opposed to high impedence ones which are black with red tops


would the low impedence cause uncontrollable injector firing and that my map ecu cannot shut them off either


i know map is connected properly but the map will not shut fuel off


my base setting for fpr is around 20 -25 psi

and i did notice as well that when attemping to rev car while dumping fuel the needle within fpr guage would flicker quickly on and off

[lexforlife]

are the injecotors the same impedance? As stated above, you need to pull fuel out.


i am just being informed they may be the wronginjectors i am using they are low impedence i beleive

[lexforlife]

okay guys just verified my 550 inj are in fact high imped so unless one or more are not firing correctly ( i did not have the cleaned and flow tested prior to install) i dont know what else it could be making the car dump so much fuel


can not having the rear 02 not installed have any effect on this

when the motor was removed all we did was unplug tps nothing else

does anyone havea clear pic of the correct wiring for the map ecu

i know power , o2 input , rpm, ecm ground are all correct , the map wire i might have question on

[Dan@FSM]

More than likely its the secondary O2. Best thing is to get an o2 simulator assuming you removed the cat----or incorrect wiring for the mapecu. And yeah, pull lots of fuel. I've used the very same injectors in a customers build using the APEX NEO and it only has the ability to pull 50% and it was still reading 10:1 afr on the wbo2.