gas gets to engine but not to injectors. replaced ecu. fuel pump was wired to switch and now is wired back into the harness in the correct manner. fuel pump does not turn on but will turn on when it is wired into switch. engine started on starting fluid and ran fine. compression is good. i was told to check the trailing coil wire i believe it is yellow with a green stripe. what is involved in checking this and does this wire kind of act like a crank angle sensor?? please help!!!!!

 

First off - the high pressure fuel pump used for EFI on a 13B RE-EGI is only pumping if you are cranking the engine, or when the engine is running. In other words, you will not 'hear' the fuel pump running with the key switched on, but not running.

You can check this first (and important) feature by finding the plastic plug over by the variable rheostat, next to the air filter assembly that has 2-poles- this is the fuel pump shunt connector. Short these 2 poles together with a piece of wire and 2 spade connectors and then turn the ignition key to on. This will allow you to pressure test the fuel injection system (and verify fuel flow) without the engine running.

If all's in order, you'll hear a 'hissing' sound which is the fuel coming from the tank, to the fuel rail and back to the return line to the tank. Obviously, the injectors will not be firing at this point, since the engine isn't turning.

The trailing ignition wire is used as a lead to the tachometer to feed it's rpm signal, and also to the ECU to tell the computer how fast the engine is turning. If this isn't hooked up correctly (short or broken connection), then your ECU will not know how much fuel to supply via injector pulse width and duration.

From there, you'll need to check the standard stuff, like ignition timing, distributor cap and rotor, plugs, plug wires, etc. to be sure that your engine is in good shape.

Did you actually get it running after starting fluid? Hard to tell from your first post, above,

 

I would first start off by seeing if you have spark to the trailing coil. Just pull off the high tension wire from where the trailing coil connects to the distributor cap and place it next to the chassis. Crank the enigne and look for spark. If you have no spark, you may have a bad igniter or there may not be power to the trailing coil.

The other possibility is that the one of the negative wires on the trailing coil has came loose. There should be two connection to the negative terminal on the trailing coil. One is yellow w/ green stripe and I believe the other is black (goes to ECU). If you have spark and the wiring checks out, I would then check the voltages on the ECU. The approximate voltages for each pin is shown in the Haynes manal and the FSM. You may have no power to the ecu (bad fuse, or wire) or the injectors could be shorted.

Hope this gives you a staring point to work from.

Kent

 

yes, it did run on the starting fluid. ran ok, but wat do you expect form starting fluid. next to the ecu, there are various other relay looking things. do they perhaps have anything to do with my problem. i am not sure if my problem lies in the trailing coil wire, as the engine ran (on starting fluid) and the tach works fine.

 

injectors are fine fuel pressure is great, it just doesn't get in the engine, only to the first rail where the rubber hose connects. just replaced the ecu.

 

If fuel is not returning to the tank, then somethings cloged or stuck. pull the delivery pipe, be carefull of the grommets on the injectors though. you can also turn the key 'on' and open the flap/door in the aircleaner assembly to test the fuel pump/presure. New plugs too.

 

new plugs in, i'm pretty sure fuel does return to tank.

 

pull the return line to test......right next to fuel 'in' hardline.

 

Any progess, mazdaverx713b? I would still check the trailing coil wire if you are sure that you are getting fuel to the rail. There is a yellow w/ green stripe wire that goes to the trailing igniter and the tach. There should also be a shielded black wire connected to the negative trailing coil terminal that goes to the ecu. If this connection is fine, I would then check the voltages on all of the pins to the ecu. There may be no power to the ecu or a bad ground for the ecu or injectors.

You could also test to see if you are getting the signal from the ignition to the ecu. I would use and LED with about a 600 ohm or more load resitior. Connect the longer lead of the LED to the 'U' terminal of the ECU. Connect the shorter lead of the LED to the load resistor and the other end of the resistor to ground. Crank the engine. If the LED blinks, then you know that you are getting the coil signal to the ECU.

Kent

 

kent, there is more evilness i have discovered!!!!! behind the air filter, there are two electrical connectors. one with a green end and another with a clear end with a boot on it. i have nothing plugging into these!!!! i think i am missing both and need them!!!! i think one is the variable rheostat.. i think. i have the thing that is round and mounted to the bracket. i do not have the little guy with the screw looking thing. i sound like a moron here, i realize this, but i am new to the gsl-se's components and someone had put a 12a into this gsl-se andd i am converting it all back. replaced the ecu i got from another member here and no difference. i had not checkes the coil wire, but i had the engine running on starting fluid and the tach worked fine. i really think i need whatever plugs into these two connectors to make my car run properly. but again, i ask for help on these two connectors. thanks a ton, dave

 

Dave,

Those two connectors do not need to be connected to anything. The one with the boot and two connectors is the fuel pump short connector. This is used so that you can test the fuel pressure without the engine running. If you put a jumper wire between them, you should run the fuel pump running when the key is in the on position. The other connector is for adjusting the tps (throttle position sensor) The tps adjustment shouldn't effect the starting. Once you get it running, there is a thread in the first gen archive on the tps adjustment.

The variable resistor has a green round connector with three pins. If you are missing the variable resistor, you will need to get another one. This is used to adjust the mixture at idle.

BTW, the engine can run (with external fuel supply, like starting fluid) and the tach can still work with the second wire off the trailing coil. As I said before, there should be two connections on the negative side of the trailing coil , one yellow w/ green stripe (goes to igniter and tach) and the other is black (goes to ecu). Make sure that you have the black wire connected.

Kent

 

both wires are connected. i will have to test for voltage in all areas that you specified. thank you again for your help. well i am off to search for this infamous variable resistor. thank you again, dave!!!!

 

Dave, do you have the factory service manual? You can download each section at:

http://www.wankel.net/~krwright/cars/rx7/85_manual.html

I have found it extremly helpful. You will probably want to start with sections 4b and 50. Section 4b will have all the info on the variable resistor, ecu voltages, etc. Section 50 has all the wring diagrams that you are going to need. Hope you get it figured out. You can also PM me if you want for further help.

Kent

 

thanks, i really appreciate it! i do have the fsm. as well as the haynes manual. i'll see what i can do. i'll keep you posted. thanks, dave

 

i think the AFM has to be connected and working properly for the engine to get fuel? im SE ignorant tho... but remember seeing it mentioned on here

 

Can you verify whether or not the injectors are working properly..spraying fuel, etc?
Check for voltage on connectors to the injectors on the harness themselves.. after two decades they do get brittle and not make proper electrical contact.
While the injectors are out.. check the air bleed sockets and replace as necessary.