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Hello everyone, I’m new here but I have watch many videos of Eric the car guy, lol….I also have a little knowledge of simple mechanical issues. Anyways I have a 94 Honda civic for 18 yrs so I know a little of how it works, but this time it’s eating me, lol…..
It he car has been sitting for a long time, I would turn it on n take it for a spin 1x 2x a month, I had give me fuel pump problems from sitting on old gas, after a spin around the block I would shut it off and it would start also it has shut off by itself. After waiting for a while it would start. The fuel pump would not prime, since I have never replace it n been sitting for long so I decide to replace it, come to find that it still not priming, so I check the relay (pgm-fi) main, and also replaced the fuel pump relay. Now still NOTHING, no prime.
So I did a few troubleshooting…..spark plugs, igniter,rotor, coils, and even thought that the coils had some oil when I open it, everything has spark. I also did some relay troubleshooting ,I put a continuity tester from #1 n #7 and apply 12v to the relay, #2 been my grnd and #5 been +, now I get a clicking sound like the relay its closing but no continuity between the pump and anything. Not sure if I’m doing this right, but I NEED HELP……. I have included some pictures of the relay, diagrams of relay, and top of fuel pump. Also I check for fuel pressure by turn the ignition to the on position and fuel coming out of the filter, also I forgot to to said that out of the top of the pump I’m not getting any power with or without the ignition been on, hope I have explain good so ur guys can help me, thx…rob….
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Just because you install a “new” part doesn’t mean it’s good.
Retest your ignition switch with ohn meter in all positions.
If ignition switch is good; check relay connenctor/plug pins 1, 5, and 6 again.
Need to find what supply input is missing if any.
Ensure your clutch safety interlock is good by checking it with ohn meter.
I would also get a known good relay and replace.
Also, you did replace your fuel pump with a “new’ fuel pump.
I remenber reading somewhere Eric said Honda OEM fuel pump almost never go bad.
Maybe you should re-install your OEM fuel pump back again.
Intermittance electrical problems are very hard to troubleshoot.
Good luck.I replace the fuel pump with new 1..I just start it checking my fuses with my tester, number 23 when I push it with the tester to check that it didnt blew a fuse, the fuel pump came on. I tested the pump with the keys in and it came on and off a couple of times when I came back 20 minutes later and the pump still come on. I started the car and acelerated for a few minutes and turn it off, try to start it back on and the pump didnt come on/prime….i spend a $100 on a new pump for me to put the old back on…lol….put the clutch dont have to do with the pump not priming?…by having the car on for a few minutes, i dont think it was enough for the relay to heat up right?…i can troubleshoot High Voltage lines..lol…but when it comes to cars its a bit harder….lol
Need to find a better wiring diagram that show all supply inputs that effect this main relay.
A clutch interlock switch supply only one of many 12vdc input to ECM/ECU computer.
The ECM/ECU computer supplies the ground for the main relay.
I an using wiring diagram from http://www.bbbind.com for your make and model.Lets try this now.
Unlacth rear seat back rest and let fall forward.
Do not disconnect connecter/plug at fuel pump.
Place volt meter on back seat so that you can see meter from drive seat.
With one test lead on gound and the other lead place into connector/plug at fuel pump.
Every time you start the car, you must have 12vdc at connect/plug at fuel pump.
Let me know your findings.Well I couldn’t start the car, because the pump its ot coming on, but with the volt meter on the plug, I turn the ignition to start the car ands the pump primed too quick, I was able to see 4volts one time and the others 0volts because the pump was not priming.
Now disconnect the connector/plug at fuel pump.
Leave the test lead connected from volt meter to connector/plug of fuel pump.
Start/crank the car and check for 12vdc.Does your connector/plug at fuel pump has two wires?
If so, move other test from body ground to wire on connector/plug,
Re-check for 12vdc.The volt meter MUST read 12 vdc everytime your start/crank the car.
If 12vdc is missing at connecter/plug of fuel pump, need to working back to main relay.
At main relay check for volts again at pins 1, 5, and 6.hey I disconnected the plug, yes my oump plug has 2wires…findings were……12v when ever it decide to work.because sometimes 0volts…i also went to the chassi for grnd and the same sometimes yes and no VOLTS….i go back to the relay and i get 12-14vlts on the #1 pin,#5 i get 12v-14v when key is turn on.#6 i get 11volts when the key its tuen to the start/crank position.
Lets back up.The main relay is two relays in one. when
the ignition is turned to the start position. one set of
contacts supplies power to the ECU and injectors. The other
set supplies power to the to the fuel pump for aprox 2 seconds
to prime the fuel line.When the engine is cranked and running
power is then supplied to the fuel pump.College man is correct.
Main relay has two contacts and two coils.
Each coil has different grounds.
One coil uses body as ground.
The other coil ground is control by ECM/ECU.To save time—-please replace main relay.
I know you posted that you tested main relay and said main relay was good.
But relay do fail only under a load sometime and this can be the problem now
After you install a new relay, try to start car.
Don’t forget to reconnect the connector/plug at fuel pump.IF main relay does not fix problem, then need to check both grounds to main relay.
Ok..i think its electrical..like a ground its not make a good contact. Only when ever it feels like….because it turn on whenever, i eeplaced the fuel pump, ignition electrical switch, and im going to replace the main relay next and see…i know troubleshooting its a process of elimination, i go thru it at work with high power lines as im a lineman but damm this is takin dayssss…i let u guys know as soon i get a new relay…thx
Ok guys I just got a NEW Relay and Nothing….1st try it didn’t start, 2nd try pump came on, 3rd try nothing, 4th try pump came on and I started the car let it run for about 5mins, turn it off and try it again for the 5th try and NOTHING……so as I stand I have Replaced fuel pump, ignition electrical portion, main relay and still the pump come on when ever it feels like it…..lol…..I guess my next step is to follow the 2-grounds from the relay and see….I guess 1-goes to the body and the other to the computer/ecu right?..
Yes, now need to check both grounds.
Lets do ohm check first.
Remove new main relay.
At main relay connector/plug, check pin 2 to body ground.
Zero ohm = good ground
Any amount of ohms = bad; check wire from connecter/plug to body ground for loose/bad connection.Next, need to check ECM/ECU ground with ohm meter.
Disconnect battery to prevent damage to ECM/ECU.
Disconnect connector A from ECM/ECU (should be largest plug with 28 wires).
Remove new main relay.
At main relay connector/plug, check with ohm meter pin 8 to ECM/ECU plug A pins A7 and than A8. Pins A7 and A8 wires are both green/yellow in color.
Zero ohm = good wire.
Any amount of ohms = bad; check wire from main relay connecter/plug to ECM/ECU pins A7 and A8.If all ohm checks are good, now need to check for voltage drop at output of main relay.
Only going to check voltage drop at main relay pin 8.
Reconnect plug A at ECM/ECU, than battery and then main relay.
With volt meter, one test lead to body ground and the other to pin 8 main relay connecter/plug.
Start car— if car does not start—-check volt meter while car is cranking.
IF any voltage = ECM/ECU is not providing ground.
Volt meter should read 0vdc when car is running.ECM/ECU has many inputs and outputs
Some are 5vdc, 12vdc. logic low and logic high.
One input is the clutch interlock switch.
Can you ohm out this switch and test 5 to 10 times.Good luck
Ruben
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