fuel pump problems! HELP ME HONDA-TECH your my only hope!
11-02-2007, 11:27 AM
#1
fuel pump problems! HELP ME HONDA-TECH your my only hope!
I recently installed a walbro 255 fuel pump on my civic. Before the install the car was running with the stock pump, i pulled the motor, then pulled the pump.
After installing the walbro, i put my motor in, i decided to check and see if the fuel pump would kick on after that, IT WONT! Its a NEW working pump, i know it works because i took a wire from the battery and jumped it. I have a multimeter, so i started checking for voltage on the wire that starts the pump, it doesnt get any voltage!!!!! SO NO POWER TO THE PUMP! what could cause this?
I pulled my main relay and the little black relay the is up inside the drivers side of the dash - i swapped them with the ones off my friends coupe (his runs like ****, but it runs!!). My relays worked fine in his car. After putting the relays back on my car, i observed that it doesnt sound like the relay is clicking enough - not getting enough voltage?!? its getting 11.8 V and the battery is reading like 12.3 i think (not sure on the bat)...
Obviously there could be a short somewhere, but how do i find it? what could i have done wrong? its not the first time ive swapped a motor, but this is the first time my fuel pump doesnt get power....
Any help would be greatly appreciated, i want to have a car again!!
After installing the walbro, i put my motor in, i decided to check and see if the fuel pump would kick on after that, IT WONT! Its a NEW working pump, i know it works because i took a wire from the battery and jumped it. I have a multimeter, so i started checking for voltage on the wire that starts the pump, it doesnt get any voltage!!!!! SO NO POWER TO THE PUMP! what could cause this?
I pulled my main relay and the little black relay the is up inside the drivers side of the dash - i swapped them with the ones off my friends coupe (his runs like ****, but it runs!!). My relays worked fine in his car. After putting the relays back on my car, i observed that it doesnt sound like the relay is clicking enough - not getting enough voltage?!? its getting 11.8 V and the battery is reading like 12.3 i think (not sure on the bat)...
Obviously there could be a short somewhere, but how do i find it? what could i have done wrong? its not the first time ive swapped a motor, but this is the first time my fuel pump doesnt get power....
Any help would be greatly appreciated, i want to have a car again!!
11-02-2007, 12:05 PM
#3
11-02-2007, 12:08 PM
#4
Re: fuel pump problems! HELP ME HONDA-TECH your my only hope! (wrx-killer-Sti-eater)
yes sir. you mean the two wires that are connected with a 10mm?
i thought the fuel pump would still come on without a motor in the car...?!?! is this not true?
anyway, the motor IS in the car and all the electrical plugs are hooked up.
i thought the fuel pump would still come on without a motor in the car...?!?! is this not true?
anyway, the motor IS in the car and all the electrical plugs are hooked up.
11-02-2007, 12:13 PM
#5
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Re: fuel pump problems! HELP ME HONDA-TECH your my only hope! (nabin)
get a meter and make sure the main relay is geting power and ground. ALso scheck all fuses and make sure you did not blow any of them.
11-02-2007, 12:30 PM
#6
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Re: fuel pump problems! HELP ME HONDA-TECH your my only hope! (wrx-killer-Sti-eater)
K.I.S.S. 
.... did you check the 15A fuse that powers the fuel pump if its not getting any power?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nabin »</TD></TR><TR><TD CLASS="quote">
i thought the fuel pump would still come on without a motor in the car...?!?! is this not true?
</TD></TR></TABLE>
Not true because it needs the main relay to power the pump, the ground for the main relay is on the motor. Now if you ground the main relay somewhere else then yes this is true.
.... did you check the 15A fuse that powers the fuel pump if its not getting any power? <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nabin »</TD></TR><TR><TD CLASS="quote">
i thought the fuel pump would still come on without a motor in the car...?!?! is this not true?
</TD></TR></TABLE>
Not true because it needs the main relay to power the pump, the ground for the main relay is on the motor. Now if you ground the main relay somewhere else then yes this is true.
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11-02-2007, 01:26 PM
#8
Re: (Relic1)
checked all fuses and they were good, im going to check again, just for the hell of it. where is the 15 amp fuse you guys are talking about so i can be SURE to check that one specifically. There is a 7.5 amp fuse under the dash that connects to the blu/white wires on the main relay. i thought this powered the fuel pump?!?! i checked it to see if it got hot in start and it did not, but i checked it on my friends car and his runs, and the wire doesnt get hot there either, so im ruling that out.
i used a multimeter to check the main relay. the ground is grounded, and it is getting 12.2V on the hot-at-all times wire until i turn the ignition then it become 11.8v. when it is 11.8 you can hear the relay try and click over, but its like a halfassed click. Also when the ignition turns on, three other wires read 11.8-11.9. SO ive got voltage moving around, just not enough.
The car ran perfectly fine before this.
i used a multimeter to check the main relay. the ground is grounded, and it is getting 12.2V on the hot-at-all times wire until i turn the ignition then it become 11.8v. when it is 11.8 you can hear the relay try and click over, but its like a halfassed click. Also when the ignition turns on, three other wires read 11.8-11.9. SO ive got voltage moving around, just not enough.
The car ran perfectly fine before this.
11-02-2007, 01:49 PM
#12
Re: (Luserkid)
how would i know if there is a short in a wire? i have a multimeter to test it, what would it read? if you touch the leads on the multimeter together, you'll get zero so i know if its on the same wire it will get zero or close to it. how do i tell if its shorted out?
11-02-2007, 01:51 PM
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wires at the main relay
black/yellow - ignition power (12V in run or start) from 15A in underdash fuse box
yellow/white - 12V all the time from 15A fuse in underhood fuse box
yellow/black - output of relay from yellow/black, black/yellow signal to turn on coil
blue/white - 12V in start only, otherwise 0V
green/yellow - signal from ECU to turn on fuel pump (ground active)
yellow/green - output of relay from black/yellow, green/yellow(ground active) to turn on coil
black - full time ground
test to make sure that the yellow/green wire at the main relay is connected to the same colored wire at the fuel pump. and that they are not connected to ground. (with the pump unplugged)
black/yellow - ignition power (12V in run or start) from 15A in underdash fuse box
yellow/white - 12V all the time from 15A fuse in underhood fuse box
yellow/black - output of relay from yellow/black, black/yellow signal to turn on coil
blue/white - 12V in start only, otherwise 0V
green/yellow - signal from ECU to turn on fuel pump (ground active)
yellow/green - output of relay from black/yellow, green/yellow(ground active) to turn on coil
black - full time ground
test to make sure that the yellow/green wire at the main relay is connected to the same colored wire at the fuel pump. and that they are not connected to ground. (with the pump unplugged)
11-02-2007, 04:02 PM
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green/yellow is a ground signal from the ECU.
it should have 0V on it when the fuel pump is supposed to be on.
try your buddies ECU. an increasingly common problem with honda ECUs is a capacitor going bad due to age, it kills the fuel pump output line.
it should have 0V on it when the fuel pump is supposed to be on.
try your buddies ECU. an increasingly common problem with honda ECUs is a capacitor going bad due to age, it kills the fuel pump output line.
11-02-2007, 06:18 PM
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Re: (tannerLSt)
Do this, how are you checking ground. It sounds like the relay is pulling ground from the fuel pump wire. Get a spare peice of wire from somewere and tag it to the ground wire on the main relay wire. and ground it to a good spot. And report back.
11-02-2007, 08:57 PM
#22
Re: (wrx-killer-Sti-eater)
HOLY **** *****!!! that was my problem! i tacked the wire in like you said, and ta-da! WERD!
so if im getting a faulty ground, should i worry about it and try and trace the problem? or just leave that wire tapped into the relay?? if im supposed to find the problem, how do i do this?
THANKS again for everyones suggestions, and DOUBLE THANKS to you mr. wrx-killer
so if im getting a faulty ground, should i worry about it and try and trace the problem? or just leave that wire tapped into the relay?? if im supposed to find the problem, how do i do this?
THANKS again for everyones suggestions, and DOUBLE THANKS to you mr. wrx-killer
11-03-2007, 08:11 AM
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so the black wire at the main relay is not grounded?
trace the wire back to the point, there are more wires that use that same ground.
unless it's on a switch for a fuel cut...
trace the wire back to the point, there are more wires that use that same ground.
unless it's on a switch for a fuel cut...
11-03-2007, 12:05 PM
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Re: (nabin)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nabin »</TD></TR><TR><TD CLASS="quote">HOLY **** *****!!! that was my problem! i tacked the wire in like you said, and ta-da! WERD!
so if im getting a faulty ground, should i worry about it and try and trace the problem? or just leave that wire tapped into the relay?? if im supposed to find the problem, how do i do this?
THANKS again for everyones suggestions, and DOUBLE THANKS to you mr. wrx-killer</TD></TR></TABLE>
No problem, This happens alot during swapps. Is the tranny and engine grounded. That thermostate housing might no be well grounded. Or the engine and tranny. This is going to give you codes popping up all over the place soon. This is a teporary fix. You need to find out were that weak ground is because something else is going to be effected. Or double up that wire and ground it and the other units will pull ground off it. But like I said its temporary and you need to find out the main problem. You can now drive the car.
so if im getting a faulty ground, should i worry about it and try and trace the problem? or just leave that wire tapped into the relay?? if im supposed to find the problem, how do i do this?
THANKS again for everyones suggestions, and DOUBLE THANKS to you mr. wrx-killer</TD></TR></TABLE>
No problem, This happens alot during swapps. Is the tranny and engine grounded. That thermostate housing might no be well grounded. Or the engine and tranny. This is going to give you codes popping up all over the place soon. This is a teporary fix. You need to find out were that weak ground is because something else is going to be effected. Or double up that wire and ground it and the other units will pull ground off it. But like I said its temporary and you need to find out the main problem. You can now drive the car.