1990 CRX no voltage at fuel pump.
03-30-2015, 07:19 AM
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1990 CRX no voltage at fuel pump.
Let me begin by saying that I replaced the main relay with a working one right out of my other perfectly running CRX.
The car is bone stock, no aftermarket radio, no alarm, no kill switch. Its been parked in dry ( sometimes very hot) storage for a long time (3 +years) and it was running before it went into storage.
I unplugged the fuel pump connector under the storage bin on both CRXs and going from right to left on the plug, the first wire I get 12 volts on my running CRX. On the non running crx I get zero volts. So that's the problem. No voltage at all on the wire that runs the pump. I know that the ECU primes the pump for about 2 seconds and then turns it off. It works that way on the running CRX but on the non running CRX I get zero volts constant, no matter what I do.
What else could it be, a bad ECU?
I would like a few opinions before I go sourcing another ECU.
Thanks in advance!
George.
The car is bone stock, no aftermarket radio, no alarm, no kill switch. Its been parked in dry ( sometimes very hot) storage for a long time (3 +years) and it was running before it went into storage.
I unplugged the fuel pump connector under the storage bin on both CRXs and going from right to left on the plug, the first wire I get 12 volts on my running CRX. On the non running crx I get zero volts. So that's the problem. No voltage at all on the wire that runs the pump. I know that the ECU primes the pump for about 2 seconds and then turns it off. It works that way on the running CRX but on the non running CRX I get zero volts constant, no matter what I do.
What else could it be, a bad ECU?
I would like a few opinions before I go sourcing another ECU.
Thanks in advance!
George.
03-30-2015, 10:36 AM
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Re: 1990 CRX no voltage at fuel pump.
I forgot to mention it's a DX automatic. No blown fuses, I started there.
Replaced the ECU with another one, no check engine light as I crank it.
WTH!
Replaced the ECU with another one, no check engine light as I crank it.
WTH!
03-30-2015, 12:15 PM
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Re: 1990 CRX no voltage at fuel pump.
check the fuel pump wire at the main relay if no 12v then manually trigger the main relay from the ECU wire and it if turns the main relay on then its your ecu. I have a few ecus btw if interested...they are all Si dont think i have DX though.
03-30-2015, 12:58 PM
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Re: 1990 CRX no voltage at fuel pump.
I replaced all the fuses just in case. I bypassed the main relay by jumping the ignition 12+ to the fuel pump wire and I finally have 12 volts at the fuel pump plug on #1. I put the main relay back on and it cycles like it should. 12 volts for 2 seconds then down to 6 volts at the fuel pump plug. The problem is a bad ground at the fuel pump. If I remember correctly, the ground wire at the pump screws to the pump bracket but there isn't a hard ground connection. I am dropping the tank and putting a dedicated ground wire for the fuel pump all the way to the chassis. It is still a bit of a mystery why I wansn't getting any voltage at the pump, it works now. I hate it when things work again and you don't know why.
Will update when I do that.
Thank you all!
Will update when I do that.
Thank you all!
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