i know there is countless threads on this and i have went through them trying to find a fix the problem. Basically i have replaced stock fp with grams 320 lph and it was working fine then it would only work every so often. I went through steps i have checked all my grounds, put new main relay. now it doesnt prime at all so i tried to resolder my old main relays thinking i got a bad one. no luck on those either. i pulled the fuel pump to check ground on that and it was good. i have also checked the ignition switch too and tried a different one too. i was wondering what the next things to check would be if i cant figure this out soon i was just going to bypass the relay and run a power wire with a switch to the fuel pump power. I hate to do things that way but when the fuel pump does prime it starts right up and i am running out of things to check. car is a 93 dx ej2

 

Are you getting power to the plug?

 

Check voltage and grounds at the ecu

Check signal wire from ecu to main relay

The pin outs are all online you have to find those yourself

You could have a burned circuit in the ecu

 

checked voltage and grounds at ecu good there, i just got my ecu back from hondata so i really hope i didnt burn a circuit ive tried so many main relays but i have another car i think i am about to pull the relay from it and give it a try not getting any power to the pump but i do hear the relay click

 

Theres 2 coils in the relay

You need to probe it and find the pin that sends voltage out to your fuel pump

The way this works is

Ecu gets voltage at igp1 and2

Then it provides a ground to the main relay

That excites the coil inside closing the contacts and voltage is allowed to travel to the fuel pump

 

Open your ECU and check the capacitor at C14 (near the ECU's plugs). It is common for this capacitor to blow resulting in the fuel pump not priming.

 

Op start at the component work your way back

Check for 12v at the fuel pump and for ground

Then do all the other suggestions

For all you or i know the fuel pump can be shorted

 

fuel pump is grounded good and used a power probe to push power to it and it kicked on so fuel pump is good and check voltage to power with ignition on and no power getting to pump. Tried spare ecu just to see if pump would prime and nothing so i think its in the wiring in between the ecu and the relay...i am getting close to the end of my expertise in wiring but i was going to pull the dash out and just trace wires to make sure there isn't a break or bad connection somewhere

so far i have eliminated the fuel pump being out or a bad main relay and pretty sure ecu isn't bad

I try to work on and check as much as i can until i get frustrated or I gets too cold then i usually quit for the day

 

You only verified that the pump works, how did you verify if the main relay was bad?

 

relay is brand new and i have an integra also that runs, just to check to make sure the problem wasn't the relay i pulled the integra relay and tried it in the civic and still no prime so i put the relay back in the integra and it still started right up. i also i have 2 spare relay's that i resoldered and tried

 

You need to kjow how to use a multi meter op

Its not hard to learn to use one

This problem can be fixed in literally 15 min

 

car wiring isn't my strong point and when it comes to electrical i am a total noob but i am trying to learn, if the problem was mechanical i could have figured it out by now. I appreciate all the help everyone is giving me and i am trying to check as much stuff as i can and youtubing how to use the multimeter on what i have checked already. I did check all grounds with the multimeter. my next step is checking ipg 1 and 2 on the ecu which i have a printout of the pin layout. i will be going over that today after work before i pull dash.

 

Cool man lets figure this out

 

ipg 1 had continuity and ipg 2 showed voltage followed checked through a couple of things. fiddled with the connection that connects the back harness that goes to the fuel pump by the hood latch and the fuel pump primed. i then unplugged the harness and with a pick tool i cleaned the inside of the terminal then checked that it would prime. it did 10 times in a row so i gathered up my tools started the car and was going to drive to a friends house down the street. i made it a block then the fuel pump stopped priming or running at all and i dont hear the main relay clicking anymore. narrowed down the location of the issue but i had to quit for today and go help a friend out. my thoughts are to find a donor car to get a spare harness if i cannot find where this issue is coming from. I have been working on this car for over a year https://honda-tech.com/honda-civic-d...build-3229101/ and i want it to work

 

Check whether fuse 31 or 24 is blown and whether voltage from both fuses reaches the main relay connector.

 

fuse 24 was blown and it had the wrong size in there

car works now drives without a problem after checking the wires by the plug i think one had a little bare spot and grounded out so i electrical taped it and everything is working as is suppose to now.

Thanks everyone for all the help