khemfusion

Hello everyone, I have a 1987 Turbo II RX-7, the engine turns over, and there is spark, but no fuel is flowing at all. I thought it was the fuel pump first so I bought a walbro one, installed it and it still does not pump anything.

I tried jumping the ISC and listening for the fuel pump but nothing, one of the west coast guys (scathcart) was trying to help me figure out what was up.

I checked the solenoid resistor and it was getting 12V on the blue+red wires up top, but when I checked for resistance through the solenoid it didn't seem to register (tried on all settings of the DMM)

We thought that bridging the top two (blue/red to blue) on the connector for the solenoid resistor, with the ISC jumped would put power to the fuel pump and enable it to pump fuel, however still nothing.

So a few questions, if I can't seem to get resistance through the solenoid resistor should I replace it? Since bridging the connector there SHOULD have enabled the pump to pump, and it didn't were else should I check for problems in the wiring??

fuel is the only thing this RX-7 needs to get running, thanks in advance

J-Rat

iTrader: (2)

The schematic would be helpful here....

Let me look and see whats up.

Jarrett

J-Rat

iTrader: (2)

If I am reading the schematic right, in the steady state position, there should be NO resistance. That would be power off. I think that it stays in the no resistance state for a few seconds AFTER startup.

Black/White should be your signal from the ECU that changes from resisted voltage to standard voltage.

Then on either end of the relay, there is a "L/R", and a "L" wire. One set corresponds to resisted voltage and one corresponds to non-resisted voltage.

Those are your power lines.

If you want to refer to the diagram I am using..Its page 50-34 of the Wiring Diagram of the FSM.

I am looking at connector F09

Jarrett

khemfusion

Thats what I was looking at also, there should be no resistance, but the multimeter just stays at 1 for each connector in the solenoid resistor, which leads me to believe it needs to be replaced, however if I bridged the side leading from the harness should this not give the fuel pump power to pump?

I'm not very good with the electrical side of things here, so sorry if I'm making it confusing

J-Rat

iTrader: (2)

Right, in the steady state you will see no resistance on both wires, and I will try to explain why.

The wires are tied to gether. And your signal is going to take the path of least resistance. With the switch closed, both wires see a short (no resistance).

If you remove the connector and test JUST the resistor box, you SHOULD get the numbers you are looking for.

You are measuring the resistance through the 2 ends of the connector. Try the measurement on the box itself not at the connector...

I wish I could be more clear...Where is HAILERS with his schematics when you need him?

Jarrett

khemfusion

If there is nothing wrong with the solenoind resistor, what else would you suggest for me to check, the fuel pump is not getting enough voltage to turn on, I do not know what else I should be checking

J-Rat

iTrader: (2)

Well, start at the pump...See if the 12 V signal wire is getting back there. If it is, then your pump or the ground may be suspect. If no 12V, but the solenoid resistor is working, I would start looking for a broken wire. Make sure the 12V is getting through the solenoid resistor. If you have to, bypass the resistor by jumpering the 2 ends of the connector together (as I read the schematic, I take NO responsibility for what happens ).

Remember the signals you are concerned with are at BOTH ENDS of the connector. And this 12v signal comes from the AFM.

khemfusion

The pump is not getting 12V (and it's not a problem with the pump because I just installed a brand new walbro one, and I'm pretty sure it's impossible to reverse the polarity with this install)

I tried bypassing the resistor altogether using a bridge between the connector, and tried listening for the fuel pump to run, no go, you mentioned the AFM, I had the AFM disconnected while I was trying the bridging of the solenoid resistor.


Do you know of a good way to test the resistor to make sure it's not defective, and also where the wires run for the fuel pump so I can check that?

The fuel pump currently gets a fluctuation between 0 to 1V when I tested the wire with the multimeter and the ISC jumped with the key set to on

J-Rat

iTrader: (2)

Okay, no problem. Then we know there is no 12V getting to the back of the car. Thats a step in the right direction.



Then dont look for 12V at the connector, it shouldnt be there.



Shoot, you should be able to hear it! Turn the key on and listen in the engine bay. 19 secs or so later you should hear a click, thats the solenoid going to resisted mode.

The ISC has nothing to do with the fuel pump. YOu need to be concerned with the fuel pump test connector on the passenger side of the car. Yellow test connector.
Jumpering this connector should cause your pump to run whenever the key is on.

Jarrett

khemfusion

Sorry, I thought that one was called the Initial Set Connector

Should I have the yellow connector jumped here when I'm listening, with the AFM attached?

I got 12 volts checking the L/R wires on the connector last night with the AFM disconnected, so I think that is weird

J-Rat

iTrader: (2)

No, the fuel pump jumper should power the pump regardless of wether the AFM is hooked up or not

dr0x

Do you have a fuel pump kill switch? Its something a lot of people over look...

khemfusion

??? Not to my knowledge ???

dr0x

Look at the fuel pump relay under the dash. Is the black/white wire cut and have 2 new extension wires running to some where else?

khemfusion

I'll take a look tommorow, thanks everyone for the quick responses tonight

khemfusion

I took a look under the car in the jumble of wires today.
Everything seemed alright except for these two things which struck me as odd

Black(red tracer) and Black (green tracer) going to a connector that went to two Black (w/green tracer) wires just twisted together

WTF, anyone know what this is and why it's just twisted together

Another one was this loose connector which looks like it should be plugged into something

5 pin connector
wires: red, black(brown dots), green, green(yellow tracer), green(red tracer)

There were also a few more unplugged connectors there, but they all had only two wires so I assumed they were test connectors (small connectors also)

edit: fuel pump relay, what does this look like under there, haha, also, what is that hard drive looking thing mounted under my steering wheel?

khemfusion

Hard Drive looking thing == Emission Control Unit
also, I found out what the disconnected 5 pin connector was, on page 50-119 of the Factory Service Manual, it is the Top one that says "To Front Harness" what is this supposed to plug into?

(Wires counterclockwise from conector: G/R, G/Y, G, B, R)

Still looking for the connector that is twisted together

HAILERS

See page 50-102 and the Pwr Door Lock page. Its called FR-04.

If you have any difficult questions, be sure to ask. Just note that if, say your car has no Theft device....the plugs still exist. Same if you have no pwr windows, the plugs still exist, but the window motor or theft unit or whatever will not be there.

khemfusion

Oh, I think the twisted one is the clutch switch, fits the description and I recall being able to turn over my engine without depressing the clutch pedal

I think I'm going to do this for my fuel situation, http://www.1300cc.com/howto/how2/rewire.htm any concerns members here have?

khemfusion

The car is running now, just to let everyone know
I rewired the fuel pump

J-Rat

iTrader: (2)

Can you be more specific in case someone else has this problem?

khemfusion

Sure no problem

My Situation: Engine turns over fine, but not getting fuel, various checks of different mechanisms that effect the fuel pump all seemed okay (AFM, Solenoid Resistor). So the final thing it could be was the wiring from somewhere in front to somewhere in back, thats a huge mess to sort out and the re-wiring procedure on 1300cc is recommended over the stock wiring because it produces more voltage to the pump.

I basically followed that article almost exactly, but in my case the wiring from the stock fuel pump was totally messed up, so instead of running it from the battery to a relay like they have it set up, I ran it straight to the relocated solenoid resistor with a kill switch between the fuse and solenoid resistor (Mounted the switch underside the drivers side dash)

Since it's wired to a killswitch (as opposed to the ignition activated relay) you have to turn the engine over until it starts firing and then hit the fuel pump (This process is not hard)

HOWEVER, WARNING DANGER NO:
Anyone doing this with just a killswitch should be warned that since it's not connected to the ignition any longer you should remember that if the car is flipping/rolling the fuel pump will still be pumping 40PSI of gas everywhere, and not cut off by the AFM like normal operation, so if you think you're going to be crashing, better flip the killswitch

Oh, it's probably illegal to drive like this also

blazin91dan

did u check the fuse under the dash?

J-Rat

iTrader: (2)

Cool! Thanks for putting up what fixed it.

Jarrett

khemfusion

Yes

I said I checked every possible failure point that was easy to check, the actual problem existed somewhere in the wiring, when I pulled back the carpets I noticed a hack and slash job above the stock fuel pump connector, lets just say whoever the previous owner was, was a worse electrician than me