e_deher

i am building a kit car and need help connecting my fuel system. there are two fuel hoses that were cut coming from the engine....one from the primary fuel rail and one fron the secondary fuel rail im assuming.
i want to install a fuel pump and an adjustable pressure regulator.... how would i go about that? could i use the hose coming from the primary fuel rail as the 'IN' line where i would connect the fuel pump and then use the hose coming from the secondary fuel rail as the return line where i would install the adjustable regulator which would run back to the tank....

so my set up would be: tank - fuel pump - primary fuel rail - secondary fuel rail - fuel pressure regulator - tank

the engine is a 89 13b s5 single turbo. am i right in thinking these two fuel lines come from the rails and can be used as a fuel pump and return line?

87 t-66

iTrader: (133)

there are full fuel system diagrams in the FSM

e_deher

thanks i think i have the fuel flowing through now....it goes in one of the lines and returns through the other....the engine only started when i sprayed from fuel in the intake of the engine though.....what controls the injectors? do i need a map sensor for the injectors to fire? i was thinking it would have a default setting if there is no sensor plugged in.

HAILERS2

The fuel injectors and the coil/ignitors are controlled by the ECU via the CAS signal sent to the ECU. Gotta have the CAS wired to the ECU for the injectors to work.

The ECU pulses a ground to the injectors. Those four injector wires are in the small plug on a series four car and are .........light green, light green/red, light green/white and light green/black in color and should show batt voltage any time the key is put to ON.

Also the ECU grounds have to be present for the ECU to pulse a gnd to the injectors.

e_deher

nice thanks alot...the coils are working but the injectors are not....can you explain me a bit about the CAS signal?

HAILERS2

My explanation would suck. But try this explanation............... http://rx7.pw.cx/guides_manuals/coll...ystifying.html

Personally from my way of thinking, if the LEAD and TRAIL coils are working then the CAS is sending a good signal to the ECU and the injectors should also work just fine and dandy.

IF they have batt voltage on each injector wire coming into the ECU, then the ECU should be pulsing a ground to the primary injectors when the engine is spinning.

From my experience it's my belief that when the CAS spins it creates a a/c voltage (I've done this with spinning it with my fingers with a meter on the plug....off the car) and that is sent to the ECU which massages it and does its magic of pulsing a gnd to the injector wires at the ECU.

I've never pulled a wire on a CAS for either the G or Ne signals to see what happens. I always assume that if you do that then you won't get spark or fuel pulsation.

The ECU's guts need to have a ground and maybe you missing having the ground wires for the ECU ....grounded. But if that were so then the ECU couldn't pulse the voltage signal to the coil ignitors to make them work. So I suppose that idea is out.

Check and make sure you have batt voltage on those four injector wires with the key to ON engine Off....or not.

e_deher

cools that helps....i just thought i needed a mass air flow sensor or something else plugged in...cause im missing all those sensors at the moment

HAILERS2

During START the AFM isn't needed on a stk RX-7 ..............until the rpms reach over 500 rpm. The ECU has a internal fuel map that uses ..........rpm under 500, the water thermosensor value and the signal from the start circuit to let the ECU know your starting the car. IF it sees all these items then it will deliver fuel at a predetermined amount even if the afm is not connected to the car.

IF the water thermo sensor is missing off the back of the water pump housing...........then the ECU defaults the water temp to 176* and starting a cold car will be more difficult 'cause not enough fuel will be delivered for a cold start..................but once the engine is fully heated up future starts will be normal......'cause 178*F is close to a normal engine temp. See graph in the attachments.

What series car/ECU?

e_deher

ahhhhh that makes sense....there is no thermo sensor as there is no radiator hooked up yet either....im only using the rx7 ecu to start the engine....im using a vw starter to turn the engine so maybe the ecu doesnt even know im trying to start....maybe its not sending a signal to the injectors....i guess ill have to check for 12 volts and maybe find a way to check for the pulsating ground.

e_deher

its a 1989 13b s5 single turbo from japan

HAILERS2

The ECU normally see the start signal on pin 1C of the series five ECU as shown in the dwg out of the online FSM......FUEL AND EMISSIONS section.......sub section Control System.

Pins viewed from the wire side of the elect plug attached to the ECU. Reads from right to left in a up/down fashion.

If the ECU does not see this start signal then it will use the AFM for fuel amount being delivered.

So on your project car you'd splice a wire to your starter solenoid trigger wire and run that new wire to pin 1C of the ECu plug. Pin 1C should only see this batt voltage when the key is Held to Start and it should go away when you let go of the key/switch your using to start the engine.

You don't have a afm I understand so out of curiosity I'd buy a can of starter fluid and spray no more than two seconds into the air filter assy and then try to start the engine for the few moments it'll last. Moral builder thing. Never keep a engine running by spraying starter fluid continuously into the air intake. Busts stuff up eventually doing that.

e_deher

ive tried putting fuel in the intake and it starts but dies right after....ive tried boosting the fuel pressure from 20 to 40 psi with no results....im not sure how i have the starting wire hooked up but i think i just have the ignition going to 12 volts.

im getting 12 volts at both pins of the injectors.....i ground a tester on the engine and it reads 12 volts at both the injector pins...is this normal?

HAILERS2

One wire on each injector has power going to it. On a series five that wire is colored black/yellow.

That power passes thru the injectors coil and comes out to the other wire on the injector plug.........then heads directly to the ECU's plug which gets connected to the ECU of course.

The ECU pulses a ground on that wire to make the injector open/shut.

Sorry, I've never read a injector wire that goes to the ECU. I suspect you'll read some kind of backfeed thru that wire but that's not something I'd recommend doing with a test light. Maybe a digital meter but never a test light.

Normally I'd recommend a person go to the ECU and pull the plug off with the key ON. Check for batt voltage on the wires in the plug that are colored light green, light green/black, light green/red and light green white. They should be wires in the left side of the ECU plug on the far left as you look into the wire side of the plugs on the ECU.

Like the man said in the second or so post on this thread.........the wiring diagrams and the FSM section called FUEL AND EMISSIONS is free to download on this site.,

e_deher

thanks a million that clears things up a bunch. i have a feeling the coils are working because they are grounded to the engine since i bolted them there but the ecu may not be grounded good so it cant ground the injectors how it should....what would be the best way to ground my ecu? are there wires i should ground or bolt it to a ground strap from the engine/ chassis?

e_deher

could the ecu not sending a ground signal to the injectors have something to do with a missing map sensor or other sensor? the ecu seems to be grounded at the right pins to me....the ecu is not bolted to the chassis but that shouldnt matter.

e_deher

got it started!!! the yellow/black injector wires were cut. as soon as i put 12 volts to them i heard the injectors click open and she fired up and idles even with a bunch of vacuum leaks...im guna start plugging the leaks and disabling the egr system and everything else that doesnt need for the engine to run...thanks alot for your help and diagrams

videos to come