1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

85 gs fuel pump problem

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Old Sep 17, 2006 | 02:25 AM
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From: Allen,Tx
85 gs fuel pump problem

I have a 1985 Gs that I just bought. I have plans to get this car looking and running great. I did all the usual tune-up. I found that the car doesn't have a fuel filter. It will start only if you pour gas in carb. I found that if you turn key pump is not pumping fuel. I found that the dash lights don't work. I just wonder is it's the pump is out or the car has an electrical problem. Does anyone know anything about this?
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Old Sep 17, 2006 | 02:57 AM
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Is the tach needle moving at all when you crank?
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Old Sep 17, 2006 | 11:27 AM
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Does anything inside the car work, other than the lights? If not, check the center fusible link in the engine bay. If some things work, check the engine fuse under the dash. If that's good, move on to the fuel fiter and fuel pump. They are located under the body by the driver's rear wheel.

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Old Sep 18, 2006 | 01:45 AM
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From: Allen,Tx
Yeah the needle on tach moves when trying to crank. It will start if I pour gas in carb. I took line were the fuel filter is located at apart and turned on the key, no gas coming. The previous owner did away with fuel filter and just put a straight pipe in it's place.
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Old Sep 18, 2006 | 02:18 AM
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Make sure that you have spark on the trailing ignition. The fuel pump will not run unless the engine is cranking, and there is spark on the trailing. Without both of those things, the pump will not run.
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Old Sep 18, 2006 | 09:09 AM
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From: St Joe MO
The fuel fiilter is installed between the tank and the pump, prevents tank debris from wearing/ruining the pump. Test the pump to find if it is working or not and install a filter. Without a filter, debris plays havoc on our carbs, not to mention the pump.
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Old Sep 18, 2006 | 02:42 PM
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85 models have an extra relay on the fuel pump. This relay cuts power to the pump when the engine is not running. With the key on/ engine off, there will be no power going to the pump.
Do a search for "Evil relay" and you should come up with a diagram showing the location (just above throttle pedal) of this relay, along with the locations to hook up a jumper wire to bypass this relay. That will allow you have power at the pump with the key on, regardless of whether the engine is running or not.
Here, I found it for you: https://www.rx7club.com/showthread.p...mp+relay+trick
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Old Sep 18, 2006 | 02:44 PM
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Originally Posted by Kentetsu
Make sure that you have spark on the trailing ignition. The fuel pump will not run unless the engine is cranking, and there is spark on the trailing. Without both of those things, the pump will not run.
Well if the tach needle is moving when cranking, he has trailing ignitor signal, so that's not it.

85GSman, I'd verify juice is getting to the pump while cranking (or bypass the fuel pump relay so you can verify juice to the pump with the key in the "on" position) and if so, then replace pump.

And definitely get a filter installed where it should be.
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Old Sep 18, 2006 | 02:48 PM
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Originally Posted by Rogue_Wulff
85 models have an extra relay on the fuel pump. This relay cuts power to the pump when the engine is not running. With the key on/ engine off, there will be no power going to the pump.
Do a search for "Evil relay" and you should come up with a diagram showing the location (just above throttle pedal) of this relay, along with the locations to hook up a jumper wire to bypass this relay. That will allow you have power at the pump with the key on, regardless of whether the engine is running or not.
Here, I found it for you: https://www.rx7club.com/showthread.p...mp+relay+trick

Hey that was much more complete than last time!
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Old Sep 18, 2006 | 02:52 PM
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Originally Posted by cdrad51
Hey that was much more complete than last time!
I knowed you'd be along soon enough....LOL
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Old Sep 18, 2006 | 03:01 PM
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From: Allen,Tx
wow, alright I appreciate all of your help and i'll let you know if i get it going. Thanks for all the info I just got this 85 and it's my first rx-7, so i'm a little new to this rotary enigine
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