2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Fuel pump wont turn on HELP

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Old Jul 3, 2008 | 01:18 AM
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WA Fuel pump wont turn on HELP

Ok so I am finishing up my turbo II swap but the fuel pump wont turn on. What are the reasons why that could happen? Ive searched and came up with only the main relay fuse is blown. I checked the fuse box in the egine bay on the driver's strut tower and the fuse labeled "MAIN" is good.
Also I am positive the my intake system is not hooked up right. I have searched but cannot find a picture of an intake system hooked up right to save my life. Any help/pictures would be appreciated.
Thanks,
Spencer
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Old Jul 3, 2008 | 03:08 AM
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Your AFM probably has a bad fuel pump safety switch. Try starting the car with the AFM flapper door propped open or with your old NA AFM in place. Other suggestions in this thread:


https://www.rx7club.com/showthread.p...=fuel+pump+afm

Besides that, check ALL the fuses, including the ones under the driverside kick panel.
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Old Jul 9, 2008 | 05:30 PM
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I tried what hailers suggested in the thread and what you suggested. Still not turning on. Oh and BTW its a brand new walbro 255.
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Old Jul 9, 2008 | 05:37 PM
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ENGINE and EGI fuses must be good.

The relay that controls the fuel pump has two coils that can make the relay pull in. One coil is used when the key is HELD to START.

Pull the fuel pressure line off the engine. PUll the small blade connector off the STARTER solenoid. Turn the key to START. Did fuel come out the fuel line? Starter SHOULD not work, but the pump should run IF the key is HELD to start.

IF this is a 86 car and you put a turbo in it, the wiring should not be effected for the fuel pump. You used the non turbo EM haress on the engine? Good. OR?????

Digital meters save time and money. IF you pull the fuel pumps plug on the aft side of the left rear strut tower, and put the meter positive lead on the LARGE BLUE wire in the harness side of that connector, AND hold the key to START, batt voltage should show up, showing the wiring is good.

Power to the pump follows the Green line I drew on the attached jpg.

And the ground for the fuel pump, black wire, has to be......grounded.
Attached Thumbnails Fuel pump wont turn on HELP-enginefuseagain.jpg   Fuel pump wont turn on HELP-fuelpumpagain.jpg  

Last edited by HAILERS; Jul 9, 2008 at 06:06 PM.
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Old Jul 9, 2008 | 07:25 PM
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Originally Posted by HAILERS
ENGINE and EGI fuses must be good.
they are good.



Originally Posted by HAILERS
Pull the fuel pressure line off the engine. PUll the small blade connector off the STARTER solenoid. Turn the key to START. Did fuel come out the fuel line? Starter SHOULD not work, but the pump should run IF the key is HELD to start.
Done and no fuel
Originally Posted by HAILERS
IF this is a 86 car and you put a turbo in it, the wiring should not be effected for the fuel pump. You used the non turbo EM haress on the engine? Good. OR?????
I used a TII harness

Originally Posted by HAILERS
Digital meters save time and money. IF you pull the fuel pumps plug on the aft side of the left rear strut tower, and put the meter positive lead on the LARGE BLUE wire in the harness side of that connector, AND hold the key to START, batt voltage should show up, showing the wiring is good.
Voltage shows- wiring is good.


Originally Posted by HAILERS
And the ground for the fuel pump, black wire, has to be......grounded.
it is
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Old Jul 9, 2008 | 07:36 PM
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Wait a darn minute here. If the large blue wire has voltage, and the black wire is going to ground, then if the pump isn't whirring when you hold the key to Start, the fuel pump is bad or its wiring in the tank is wrong.

The fuel pump will also run if the afm vane is pushed aft a quarter inch or so and the key is ON.

Or will run if the yellow fuel pump check connector near the right front strut tower is jumpered and key is ON.

There's some other wires in the fuel pump check connector that have voltage when the key is to ON, BUT there is only ONE large Blue wire that feeds the fuel pump.

I say bad fuel pump. Take that old pump you have and connect it to the harness. Go to START or any of the other ways mentioned and see if the old fuel pump will whirr.

IF you used the TURBOII EM harness on the engine, and did not take action with a couple of wires in it where the EM harness mates with the Front harness, then the ENGINE fuse will blow quite often. But you say you have power on the LARGE blue wire at the fuel pump connector, so the ENGINE fuse has to be good.
Attached Thumbnails Fuel pump wont turn on HELP-fuse-cover.jpg  
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Old Jul 9, 2008 | 07:44 PM
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Alright thanks. I'll switch out the fuel pumps.
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Old Jul 9, 2008 | 07:48 PM
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Originally Posted by Driftin86FC
Alright thanks. I'll switch out the fuel pumps.
Yeah, but don't remove the one from the tank. Just plug the old one on the harness and key to START or any of the other methods that run the fuel pump mentioned above. Shouldn't take but a couple of minutes.
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Old Jul 9, 2008 | 07:54 PM
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If this car has a home made Fuel Cut Switch, that might be the problem.
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Old Jul 9, 2008 | 08:10 PM
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Originally Posted by HAILERS
Yeah, but don't remove the one from the tank. Just plug the old one on the harness and key to START or any of the other methods that run the fuel pump mentioned above. Shouldn't take but a couple of minutes.
Sorry too late haha. the NA fuel pump spun with the spade connecter off the starter. When I put it back on the motor didnt try to turn over though, it just cranked.
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Old Jul 9, 2008 | 08:11 PM
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Originally Posted by HAILERS
If this car has a home made Fuel Cut Switch, that might be the problem.
I have a racing beat FCD.
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Old Jul 9, 2008 | 09:13 PM
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Originally Posted by Driftin86FC
Sorry too late haha. the NA fuel pump spun with the spade connecter off the starter. When I put it back on the motor didnt try to turn over though, it just cranked.
I think you just said the motor turned over but the engine did not start. I think.

Make sure the fuel lines are on right. Remove the RETURN line and make the fuel pump run. IF fuel pours out of it, that means the fuel lines on the engine are on right. ON JDM engines the fuel lines are opposite of the USA version. That's why I mentioned this.

A fuel cut switch refers to a homemade switch you can flip to kill the fuel pump from working. Not FCD related.

Make sure you have spark. Attach your OLD CAS to the elect plug on the car. Do not install the OLD CAS. Turn the key ON. Spin the bottom gear on the OLD CAS and listen for spark and fuel injectors clicking. You do not go to Start. Just key ON.
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Old Jul 9, 2008 | 09:16 PM
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About the harness on the engine that is TURBOII. Do you remember how it also plugs into two ORANGE colored plugs inside the passengers compartment? Not to the ECU but two ORANGE plugs up and to the right in the passengers side?

Did you make any changes to the wiring in those plugs? Like for the two wires on the alternator?
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