paulagre

Just finished putting everything together - meaning engine was out, and now engine is in with many hours and random things in between. I figured it would be simple, plug all the connectors back in, and watch it fire up. Well, it cranks. No fuel. I checked the fuel pump relay and it appears that it is grounded by the pcm and powered by the diagnosis module, whatever that is. Well I don't have power or ground. i have ground on the fuel pump side, and power coming from the ignition that wants to go to the fuel pump if only it had the bridge. There is more to this. Even if I manually push the poles of the relay together, still doesnt start. I am guessing the modules aren't sending their signals for a reason.

I noticed a ground on the inside of the engine compartment on the fender well, looked like a block ground, so I grounded it to the block...sound right?

Also the two ground for the pcm are screwed in, but there is a lone black single female connector, i think its a black and yellow wire, don't know where that goes.

radio goes on when I send power to my guages... don't understand, they are completely seperate from the rest of the harness, they are greddy guages, power/ground/light/12V-IGN. they are grounded. whenever i hook up the battery power the radio goes on, whether the key is in or not.

ObliqueFD

iTrader: (32)

Check the circuit relay. When you turn the key to the "ON" position the circuit relay routes voltage to the fuel pump relay and to the fuel pump resistor. Make sure the resistor is plugged in. Check FSM page F-108 for the schematic. Also check the two fuses inside the car behind the driver's foot rest.

paulagre

the circuit relay does not energize. it does not recieve a power or a ground to the coil side, but the switch side has power.

paulagre

It has to be something simple, like a loose connection, or just something left unplugged... because it seems like the computer is not giving the go ahead to start.

Circuit relay does not recieve power or ground on the coil side, but has both on the switch side.

Even manually pushing the poles together doesn't start the car. I am betting what ever is keeping the relay from energizing is not allowing any spark or injector pulse either. I could be wrong.

paulagre

Any body know where to find a good trouble shooting tree for no starts? I followed the manual, but its fairly non-comprehensive.

It shows you how to check for power at the fuel pump and then how to check the relay, and then it stops.

Please share anything helpful. THanks.

Mahjik

iTrader: (1)

Ok, it cranks but it won't turn over. You have verified that you aren't getting fuel? If you try to prime the fuel system, does the fuel pump run?

katit

iTrader: (1)

Do you have spark? If not - then ECU doesn't allow car to start. It goes down to few possibilities:
1. Ignition switch
2. Crank sensor (one of two) - did you connect them properly?
3. TPS (throttle position sensor)

paulagre

fuel pump does not run if I ground the Dlink terminals... I tested the circuit relay and it does operate if I give it power and ground, but it is not recieving power and ground normally.

I haven't verified spark, because I am stuck on the fuel pump not running when ignition is on. I am assuming that I would get fuel before the ecm would check for crank signals.

What keeps the ecm from grounding the circuit relay? Why isn't the diagnosis module powering up the circuit relay? Those are my questions for the time being. If I can get some fuel to flow, and I still don't start, then I will check for some spark.

Mahjik

iTrader: (1)

Have you looked at this diagram in the fuel section of the FSM?

paulagre

I used that diagram, as well as the actual wiring diagram for the fuel system. The more detailed wiring diagram shows that the coil side of the circuit relay is powered through something called a diagnosis module.

Mahjik

iTrader: (1)

The Circuit Opening Relay has been renamed in the 94+ manuals to Fuel Pump Relay. Its the same diagram as above. Did you also check the EGI relay?

The diagnostic module is listed for the airbag system.

ObliqueFD

iTrader: (32)

The circuit relay is only powered from the EGI and the ignition switch which has a 15 and 20 amp fuse.

The diagnosis connection you see allows you to manually jump connection at the diagnosis module. It does not receive power from this module normally.

Mahjik

iTrader: (1)

Unless I'm reading the wiring diagram wrong (which is entirely possible), there are two "diagnostic" labeled mechanisms.

1. Diagnostic module
2. Diagnostic connector

The connector refers to the area we usually call the diagnostic box (where we do the jumpers). The module is reference to section S of the Body Electric manual which shows it being use in the airbag system:

ObliqueFD

iTrader: (32)

Good catch Mahjik. The Diagnostic Module is located within the dash. The Diagnostic Connector is the little black box in the engine bay behind the driver's side headlight.

paulagre

Strange, I don't see any where in the diagrams showing that the EGI relay powers the fuel pump (circuit) relay. I thought the EGI was for the ignition portion of the engine controls.

paulagre

Any idea about the single pole black female connector that comes off the wiring harness on the body behind the ecu? I didn't find a mate for her. I keep thinking its related to the radio issue I disclosed further back in the post. Bad ground type thing...

Mahjik

iTrader: (1)

That's a diagnostic line for the cooling system. It can be grounded to trigger the cooling fans:

http://www.fd3s.net/fan_mod.html

paulagre

For those out there who have been throwing me their $ 0.2, thank you. Here is some late breaking news.

DId a little work last night on the FD, found engine fuse burnt, and a 15 a fuse by fuel pump circuit relay burnt. replaced them both. Still no start.

Circuit relay is getting power now on both the coil and the switch side, but the computer is not grounding at pin 1T.

1K is grounding the (speed) fuel pump relay, though.

However, if I ground the circuit relay using the diagnostic connector, the relay clicks, but the car still won't start.

paulagre

93 FD - no start.

In a long list of discoveries thus far, I have found that the fuel pump will not run with direct battery power, so I have a plane carrying a fuel pump headed this way!!

But this is not all.

PCM will not ground the fuel pump circuit relay. May be a bad computer, but I need to know how to be sure, because the FSM trouble shooting is worthless.

Plus I do not want to pay for a stock computer, I was planning on going Power FC soon, but I wanted to get through AZ emissions first before screwing with anything that might affect it.

You RX7 Gurus AWAKEN!!!

ObliqueFD

iTrader: (32)

I would start with the EGI Main Relay. Turn your key to the ON position and verify that the black and light green wire sends voltage to the Circuit Relay. Next check for continuity between the Circuit Relay and the ECU with the blue and black wire. I bet the ECU can not ground the circuit relay because of a short in the wire somewhere.

If you do have continuity, verify you have voltage from the blue wire which should be 12v from the battery. Then check if voltage comes out of the relay to the Fuel Pump Resistor. At the Resistor there is a white and red wire which leads to the fuel pump. Check the continuity of this wire and also check the voltage. You should have about 5.4 - 6.0 volts which powers the fuel pump in low speed mode.

Also I believe you can jump the the Ground and Fuel Pump connectors at the diagnostic box. The will allow you to bypass the circuit relay and provide 12 volts to the resistor, which then kicks it down to 5.4 - 6.0 volts, and then sends it to the fuel pump. You might be able to get by for awhile. Just make sure when you are done driving you disconnect the jumper so the fuel pump isn't constantly running. Can someone verify if this will work?

paulagre

The Black and Light Green wire has voltage. There is continuity from computer pin 1T (which is the blue and black wire) to the relay pin. There is also voltage at the blue wire to the relay, and if I jump the relay I get 12v at the fuel pump connector.

The fuel pump doesn't run with battery power jumped straight to it, so it definately needs a fuel pump, but something is still not right about the computer not grounding at 1T.

ObliqueFD

iTrader: (32)

Have you checked for codes by connecting GND and TEN? Something might have been fried from when the fuses burnt out. Maybe there is someone nearby that would let you borrow their ECU so you can test it out on your car.

paulagre

Great! Thanks, I wanted to check codes, but wasn't sure which pins to ground. I will try that tonight to see what comes up. I will see if I can find someone in this area with a cpu.

paulagre

Replaced the fuel pump, still no start.

Fuel pump relay still doesnt get a ground from the ECM pin 1T.

Also - Don't have spark.

Cranking is slowing down like its either flooding or the battery is going. If its flooding that would mean that the injectors are pulsing, correct? They are getting 12v with IGN on.

paulagre

Got a computer, still won't ground the relay, still won't start if I ground the relay thru the DLC. i don't know what to do at this point....