problem with main relay/harness
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problem with main relay/harness
so i have gotten my project back together, and went to start it. well i wasnt getting power to my ecu and i wasnt hearing my main relay. tore my dash back out, everything was hooked up fine. messed with my main relay and made a jumper wire and got the main relay to click. i borrowed my friends main relay and the car did the same thing so its not my relay.
the car starts this way(with the wires jumping the relay) but why. where can i check to see what the problem is. is it okay if i were to run a toggle switch and hide it? like this
the left most wire is for the power, the next is ecu and the far right one is for the fuel pump.
the car starts this way(with the wires jumping the relay) but why. where can i check to see what the problem is. is it okay if i were to run a toggle switch and hide it? like this
the left most wire is for the power, the next is ecu and the far right one is for the fuel pump.
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Re: problem with main relay/harness
No it's not OK to just add a switch, except in an emergency and only temporarily.
It should be fixed properly.
What is the MM&Y of your car?
There should be 3 power inputs to the PGM-FI Main Relay, one will be a 12V constant, [hot at all times] the second one will be a 12V switched, [hot in run and start] the third is a 12V switched, [hot during cranking to start only], there will also be two 12V outputs, one is the output from the fuel injector relay, [hot in run and start] the other is the output from the fuel pump relay, [hot in run and start only if the ECU/ECM is supplying the ground for the relays coil.
I need the MM&Y of car for wire colors. 94
It should be fixed properly.
What is the MM&Y of your car?
There should be 3 power inputs to the PGM-FI Main Relay, one will be a 12V constant, [hot at all times] the second one will be a 12V switched, [hot in run and start] the third is a 12V switched, [hot during cranking to start only], there will also be two 12V outputs, one is the output from the fuel injector relay, [hot in run and start] the other is the output from the fuel pump relay, [hot in run and start only if the ECU/ECM is supplying the ground for the relays coil.
I need the MM&Y of car for wire colors. 94
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Re: problem with main relay/harness
Before I made the little jumper my ecu would not get power, I have s300 and the lights wouldn't work, so the fuel pump wasn't priming and no spark was there.
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Re: problem with main relay/harness
If the injector relay in the PGM-FI Main Relay does not turn on the fuel pump relay will not work, there will be no power to the injectors a few engine solenoid/valves and no IGP1 and IGP2 12V signal the the ECU/ECM, no IGP signals and the ECU/ECM will not turn on the fuel pump relay or pulse the injectors.
Have you checked to see if you have the 3 powers I mentiond yet, it is a good bet it is your problem, I will see if I have wire colors when I get home. 94
Have you checked to see if you have the 3 powers I mentiond yet, it is a good bet it is your problem, I will see if I have wire colors when I get home. 94
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Re: problem with main relay/harness
I will have to guess...
Black is ground, one side of fuel injectors coil, [85]
Black/yellow should be switched ign., [hot in run and start] other side of fuel injector relay coil, [86] and fuel pump power, [internal through fuel pump relay].
Yellow/black should be injector relay output, #87 [hot when ign. is in run and start] to injectors, a few engine solenoid/valves, ECU/ECM IGP1 and 2 also to fuel pump relays coil [internal #85].
Blue/white, switched ign., [hot during cranking to start only] "back-up power for fuel injector coil, [85].
Yellow/white, fuel injector relay input, [#30, hot at all times].
Green/yellow, fuel pump relay control [#86] ground from ECU/ECM.
Yellow/green, fuel pump relay output [#87]to fuel pump.
Again I am guessing as I do not have a wire color for the 92 Civic, I am using 84-91 Civic, 96-98 Civic, 94-98 Integra, 90-93 Integra and 91-95 Legend as referance. 94
Black is ground, one side of fuel injectors coil, [85]
Black/yellow should be switched ign., [hot in run and start] other side of fuel injector relay coil, [86] and fuel pump power, [internal through fuel pump relay].
Yellow/black should be injector relay output, #87 [hot when ign. is in run and start] to injectors, a few engine solenoid/valves, ECU/ECM IGP1 and 2 also to fuel pump relays coil [internal #85].
Blue/white, switched ign., [hot during cranking to start only] "back-up power for fuel injector coil, [85].
Yellow/white, fuel injector relay input, [#30, hot at all times].
Green/yellow, fuel pump relay control [#86] ground from ECU/ECM.
Yellow/green, fuel pump relay output [#87]to fuel pump.
Again I am guessing as I do not have a wire color for the 92 Civic, I am using 84-91 Civic, 96-98 Civic, 94-98 Integra, 90-93 Integra and 91-95 Legend as referance. 94
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Re: problem with main relay/harness
i figured it out. the fuse panel that is under the dash, came with the car and didnt have the two 15A fuses in the ACG(S) spots. stupid cause to the problem but its all sorted out.
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Re: problem with main relay/harness
Sorry to jump in and add my problem. Didn't want to start another thread that's the same. Thanks
This is my problem. Main relay also. No instrument lights or power to relay but when key n ignition is cranked relay and motor starts but dies right alway. 93 civic ex. Thanks
This is my problem. Main relay also. No instrument lights or power to relay but when key n ignition is cranked relay and motor starts but dies right alway. 93 civic ex. Thanks
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Re: problem with main relay/harness
Id start checking if u have power at the relay clip. Take the main relay off. And use a test light to make sure u have a contasnt power, one when the key is at start/on and then one when u try cranking it.
Id also check fuses bc that was my problem.
Id also check fuses bc that was my problem.
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Re: problem with main relay/harness
Do you mean engine starts but as soon as you let key go from start position engine stalls?
If so... http://techauto.awardspace.com/ignitionswitch.html 94
If so... http://techauto.awardspace.com/ignitionswitch.html 94
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Re: problem with main relay/harness
hey sorry to jump in and throw my problem but i have the same problem but i did change my ignition switch but my shyt still doesn't start i have no clue what it could be any help would be greatly appreciated thanks 98 civic dx hatch
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Re: problem with main relay/harness
actually i dont hear that click i just went out to try it and didnt hear it but i do hear my fuel pump priming any thoughts on that click?
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Re: problem with main relay/harness
i would say either its your dizzy or the circuit in your main relay that controls power to the ecu for spark is messed up. im not the best at electrical which is why i made my original post. hopefully someone else can chime in.
#19
Re: problem with main relay/harness
No it's not OK to just add a switch, except in an emergency and only temporarily.
It should be fixed properly.
What is the MM&Y of your car?
There should be 3 power inputs to the PGM-FI Main Relay, one will be a 12V constant, [hot at all times] the second one will be a 12V switched, [hot in run and start] the third is a 12V switched, [hot during cranking to start only], there will also be two 12V outputs, one is the output from the fuel injector relay, [hot in run and start] the other is the output from the fuel pump relay, [hot in run and start only if the ECU/ECM is supplying the ground for the relays coil.
I need the MM&Y of car for wire colors. 94
It should be fixed properly.
What is the MM&Y of your car?
There should be 3 power inputs to the PGM-FI Main Relay, one will be a 12V constant, [hot at all times] the second one will be a 12V switched, [hot in run and start] the third is a 12V switched, [hot during cranking to start only], there will also be two 12V outputs, one is the output from the fuel injector relay, [hot in run and start] the other is the output from the fuel pump relay, [hot in run and start only if the ECU/ECM is supplying the ground for the relays coil.
I need the MM&Y of car for wire colors. 94
#22
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Re: problem with main relay/harness
If the injector relay in the PGM-FI Main Relay does not turn on the fuel pump relay will not work, there will be no power to the injectors a few engine solenoid/valves and no IGP1 and IGP2 12V signal the the ECU/ECM, no IGP signals and the ECU/ECM will not turn on the fuel pump relay or pulse the injectors.
Have you checked to see if you have the 3 powers I mentiond yet, it is a good bet it is your problem, I will see if I have wire colors when I get home. 94
Have you checked to see if you have the 3 powers I mentiond yet, it is a good bet it is your problem, I will see if I have wire colors when I get home. 94
Last edited by Adin S. Laboy; 06-02-2022 at 01:09 PM. Reason: Car missfire no injector no power to main relay everything new is a 2001 honda accord 2.3
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