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Discussion Starter · #1 ·
Finally got my engine started up built motor. got a couple it was very good for couple minutes like 20 min. then died at idling. today I drove the car on the road no problem. after I tried to start it in my driveway started and waited for my car to idle warm up for a while. then it died.

I tired restarting the car no start. I put my key on and I hear no loud fuel pump coming on. walboro 255lph fuel pump.
checked fuel gauge no dice no psi under the hood.

checked straight power at the fuel pump plug yellow green had for a while like. 2.4 to 3.0 something volts. I looked online found a fsm. someone posted about checking Honda main relay.

ive jumped the main relay driver side kick left foot panel. removed relay.
green yellow and black wire. chkeced voltage at the fuel pump connector voltage about. 12.1v same as my voltage at the gague I have.

then plugged the fuel pump connector to fuel pump then the almighty fuel pump primes. so this thing is good.

I went to the parts store. bought a relay
relay clicks ok.
checked the connector same no voltage.


what I did I checked the ground connector fuel pump side and did chassis ground with the beeping test on my digital volt meter it sounds and I seem to have ground connection from fuel pump connector.


I checked my cars thermostat ground at the thermostat it is solid sanded down and also ive used that as a ground actually upgraded it.

im confused I don't know what else to check????
 

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There's two power wires at the main relay plug. One constant and one ignition. Check to make sure they have power to them. The yellow/white is hot at all times. The black/yellow is ignition switch power.

Then once those are checked and they both have power to them,check the yellow/black wires to make sure there getting power. The yellow/black wires are the power wires to the Ecu and if they don't have power then the Ecu won't have power and fuel pump won't turn on.
 

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Discussion Starter · #4 ·
There's two power wires at the main relay plug. One constant and one ignition. Check to make sure they have power to them. The yellow/white is hot at all times. The black/yellow is ignition switch power.

Then once those are checked and they both have power to them,check the yellow/black wires to make sure there getting power. The yellow/black wires are the power wires to the Ecu and if they don't have power then the Ecu won't have power and fuel pump won't turn on.

I have power at the yellow white hot at alltimes with charger on 12.91volts

and also voltage key switch on at the yellow/black wires.
 

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I had a similar situation with my integra. Turns out it was the grounding system in the ECU for the fuel pump. Got a new ECU and works fine. Just my experience.
 

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Discussion Starter · #6 · (Edited)
ok first I thought it was the ecu yesterday I tested my ecu with another ecu a stock p28 ecu. I turn the key on it primed and found ecu is the problem. I installed the p28 chipped hondatas300 ecu and no prime wtf. so I chkeced tested again all where good fine. then I found out the stupid check engine light on my dash key on don't turn on.

wtf? so I opened s300 manager and tried to do a change in a setting and reflashed it. somehow it worked. turn key off and chkeced engine light on dash comes on and now it primes. yesterday I test drive it is ok.
 

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Discussion Starter · #7 ·
then today late in night I checked the car it primes fine after like 3 times or more. I have a voltage gauge. especially my car has a lot of gauges accessoreies I thought the voltage is too low to prime the walboro pump so I charged my batt at same time doing the tests. then it don't prime I don't hear the fuel pump go on. same even with the stock p28 ecu. both don't work. did the tests again. since I hear the main relay click I assumed its ok..

btw I installed a brand new fuel relay from napa. so I checked straight removed the relay and tested it dam it has like 3 relays in one relay. one of the test didn't have continuity. so its a defective stupid ass new relay. f**kin new relay..


I learned never ever assume a new part is ok especially if it clicks it still can be bad.
I know I was heading to the right direction the relay itself is bad..... brand new how about that?
 

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Discussion Starter · #8 ·
heres the pic what I did.
bench test a Honda relay.
It should have numbers on the relay on each terminals or check the pic.
make a wire to these conncetions. I used a butt spade connector for pos and neg and I used a dmm beeping sound for checking if it works. continuity. bench tested it on my batt.

first test
no.6 terminal battery voltage and no.8 batt ground
check continuity between with dmm no.5 and no.7

2nd test
no.5 ter. batt. voltage and no.2 batt. ground terminal.
check continuity between with dmm no.1 and no.3

3rd test

no.3 batt voltage and no.8 batt ground terminal.
check continuity between with dmm no.5 and no.7 terminals.

if either one of these don't have continuity the relay is bad.....
 

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