I ran a wire from the pos terminal of the battery to the fuel pump and with the key in the on position the fuel pump ran, but when I just try to start the car normally the fuel pump does not run. The fuses in the engine bay all look good to me, what could cause this problem? I have a fuel cut switch that Kevin Landers installed could that have something to do with it not getting 12v if the switch got messed up somehow?

 

have you rechecked all your wiring? check for current going to the pump from the wires, make sure the pump didnt die on you.

 

the pump didnt die, it runs when it gets 12v, its just not getting 12v from anywhere when I try and start it. How would I go about rechecking all of my wiring? Just trace the wires from the fuel pump and make sure they're all hooked up right and not grounding somewhere or corroding?

 

Check the fuel pump main relay. Use a jumper to bypass it, if it works then, you need to replace the relay. If it doesnt, use a test light , or a DVOM, and check to make sure you have power to the relay. Once you have determined that is good, then check for continuity from the relay to the pump. I'm sure that if the fuse is good, and you have power to the relay, then you either have a bad relay, or the computer isnt grounding the relay and turning it on. Then you need to do a continuity tset from the relay to the computer, make sure you undo the batt, before doing this, and that you unhook the computer, as a DVOM uses current to measure continuity. And probe from the back of the plug, or you could make things worse by causing a bad connection. If it all shows good continuity and the relay worked, then check the front of the connection on all the conectors to verify they are tight.

edit: bypass the fuel cut switch first before all this testing. You may find it is the root of all your problems.

Leslie

 

where is the fuel pump main relay, what does it look like, and how do I go about bypassing it?

 

Its in the engine compartment on the drivers side. Its marked , so you shouldnt have a hard time finding it.

To jump it, you need to unplug it, and check on the side of it for the schematic to its operation. Then find the side that gets power from the fuse,make sure you got power, then jump it to the load side of the relay. Not on the relay, but at the conector. When you do this, the fuel pump should come on. If it doesnt, check the wiring from the relay to the tank. If the power side from the fuse didn't have power, check the fuse again, and if its good, check the wiring from the fuse to the relay, and then from the ignition to the fuse.
If you have power to all your other acesories, you will be good from the batt. to the ignition.

edit, when turning on the key, you should hear the relay enrgize with a light click for a few seconds when you turn on the key. You will have to get some one to turn the key off and on while you feel and listen, but you can tell if its working that way. But I have seen relays that worked, but didn't flow electricity, so don't let that be the end all to a bad relay question.

Hope this helps, and I havent just confused the hell out of you.

Leslie

 

Just use the fuel pump test connector. Jumper that and see if the pump runs. If it does, I would suspect a bad AFM.

*note* You are aware that the FC fuel pump WILL NOT run when you turn the key to the "on" position unless the fuel pump jumper is installed.

 

I don't know what relay you're referring to, but there is no relay in the engine bay marked "fuel pump", and the only relay in the engine bay related to the fuel pump only affects how much voltage it receives, not whether it runs or not. The fuel pump circuit opening relay does that, and it's under the dash.

The fuel pump will only get power when the engine is either cranking or running. As J-Rat mentioned, there's a yellow check connector in the engine bay beside the RHS strut tower. Putting a jumper wire in this plug will bypass the AFM safety switch and allow the pump to run by just turning the ignition on. Do this.

 

There should be a simplified schematic for the fuel in the attached jpg: https://www.rx7club.com/forum/attach...postid=1398836

Your should make an effort to make sure the ENGINE relay is good. It's called X-07 in the simplified schematic. ENGINE FUSE BLOWN=NO FUEL PUMP=NO START

 

Man you beat me to it.

 

ok, I jumpered the fuel pump test connector and it didn't cause the fuel pump to come on with the key in the on position.

How do I go about finding out if a relay is good or not? Is this what rotilla was explaining?

 

PULL THE PLUG OFF THE FULE PUMP RESISTOR RELAY LOCATED INFRONT OF YOUR AFM. THE BLUE/RED WIRES SHOULD HAVE 12V ON THEM IF YOU JUMPER THE YELLOW FUEL PUMP CHECK CONNECTOR AND THE KEY IS TO on.

IN MY EARLIER POST I USED THE WORDS *ENGINE RELAY* WHEN I MEANT *ENGINE FUSE*.

IF THE ENGINE FUSE IS NOT GOOD....YOU WILL GET THE SAME RESULTS AS YOU STATED IN YOUR LAST POST....THE FUEL PUMP WILL NOT RUN. SEE THE SIMPLIFIED DIAGRAM I ATTACHED WITH THE FIRST OF MY POSTS. SEE THE X-07 FUSE. AS YOU CAN TELL THE SUCKER AIN'T A GONNA RUN UNLESS ITS GOOD.

 

so if im not getting 12v on the blue/red wires then I need to replace the fuel pump resistor relay, unless the main engine fuse is no good and in that case i would need to replace that fuse and maybe the fuel pump resistor relay if i still dont get 12v on the blue/red wires?

damn this is confusing the hell out of me... sorry guys. and if that diagram is simplified i'd hate to see the complicated one... haha

 

anybody know where the X-07 fuse is located and what it looks like?

 

THE ENGINE FUSE IS LOCATED INSIDE THE CAR. THERE IS A FUSE BOX NEAR YOUR LEFT FOOT.

IF YOU LOOK AT ONE OF THE FIRST THREADS ON THIS SITE CALLED *FAQ*, YOU'LL FIND A PICTURE OF THE FUSE BOX AND THE LOCATION OF THE ENGINE FUSE.

THE FUEL PUMP RESISTOR AND RELAY IS BULLET PROOF. THE CIRCUIT OPENING RELAY IS ALMOST BULLET PROOF. THE ENGINE FUSE IS NOWHERE CLOSE TO BULLET PROOF.

 

ok the main engine fuse is not blown.

I checked the red/blue wires you were talking about with the fuel pump check connector jumpered and the key in the "on" position. There definitely was not 12v on any of the wires. Just to make sure I am checkin in the right place here are some pictures of it.

 

new development.... I ran a wire straight to the fuel pump from the battery and started the car and it ran fine. I suspect that the circuit opening relay (shown in the picture) isn't working properly.... I tested the voltage to the AFM because it has to go through the circuit opening relay also and it did not register more than .34v. Does anyone know where the circuit opening relay is?

 

That's not the circuit opening relay. The relay and resistor you're holding in your hand only alters the fuel pump voltage. It does not turn the pump on and off.

The circuit opening relay is under the dash near the steering column. It has a bright yellow base so it's hard to miss.

You need to be reading the FSM. The fuel pump control system is covered in detail in the EFI chapter, and the full circuit with wire colours is in the Wiring Diagrams chapter.

 

alright, thanks. I've been trying to get to the FSM but fc3s.org isnt hosting it anymore and iluvmyrx7.com is down so where could I access it online?

 

http://www.teamfc3s.org/main/factory_service_manual

 

oops. never mind.error

 

Yes, the first picture with the Fuel Pump Resistor Relay is where you should have found 12v on the Blue wires with a Red stripe (LR) wires.

The Circuit Opening Relay should have pulled in and put the 12v on it.

Anyway, go to the Circuit Opening Relay that is just above the steering column and pull the relay plug off and see if you have 12v on the Black White wire located approx in the center of the plug. Key to ON. Jumper does not have to be installed for this. The other black/white wire should have 12v when you turn the key to START and START only.

Kinda odd. Never had problems with a Circuit Opening Relay.

 

Computer gurus: Is there a way to save this entire service manual to disk easily without clicking on and waiting for every chapter to load?

Also, those fuses inside the car can be sneaky..can't always tell if they're blown by looking. One looked fine today but was open when I checked it with a DVM.

 

circuit opening relay isnt getting voltage either... just checked the engine fuse, and now its obviously blown. I replaced it and tried to start the car and it didn't work. Then i realized i had left the fuel pump test connector jumpered so I undid that and then it still wouldn't start... I checked the fuse again and it was blown... I'm going out to try a new fuse again without the fuel pump test connector jumpered... I hope it works! If not... what could cause this fuel to blow everytime I replace it and crank the car?

 

Put in a new fuse. LEAVE the Circuit Opening Relay OUT. Crank the engine over for a couple of seconds. Now go back and see if the Engine fuse is blown.

If it is blown.......the prblem is not in the fuel pump circuit but in the MAIN RELAY circuit or possibly the ignitioon key set itself. Write back and tell us what happen to the fuse when the Circuit Opening RElay was pulled out and the engine cranked over.