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Main Relay Revealed!!!!!!!

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  #1  
Old 06-11-2009 | 05:53 PM
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can someone help me understand this relay better......im tryin to create a custom harness with toggle switches to operate the fuel pump and energise the injectors..........pluss im ganna rewire the ign switch to be a push button start.


Now my understanding of this is as follows: when u turn your key to on(II) #5 sends a 12v signal to ground #2 which in turns closes switch #1-#3 which in turn sends a 12v signal across a resistor(does anyone know the ohmage and what the remaining voltage is) to the intersection at #4 which sends a modified voltage to #8 which in turn closes switch #5-#7 which turns the fuel pump on.

now what i need to know is where does #4 and #3 come in to the factor and what effects they have and what they do........I dont want to wire anything up right now till i know exactly whats goin on here so i dont blow my ecu or burn something out


edit: I changed Title to reflect the idea i had bhind this thread
 

Last edited by Riqand; 06-21-2009 at 09:33 AM.
  #2  
Old 06-12-2009 | 06:22 AM
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The system as originally designed has an important safety feature -- if the engine stalls (for example after crashing the car), the fuel pump will stop. This reduces the risk of post-crash fire. I would not bypass that.

Nearly all faulty main relays can be repaired by opening up the plastic cover and re-soldering all the connections on the circuit board inside.
 
  #3  
Old 06-12-2009 | 07:33 AM
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By the way, how the main relay works is nicely described here.
 
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Old 06-12-2009 | 04:45 PM
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#3 is 12v power going out to Injectors and ECU and #4 is 12v power feeding straight to #8 when the key is turned to START. I think i have this figured out now. #8 is an ECU controled ground. and RonJ thank you for the really informative link that showed me exactly what i wanted to know. MK378 thanks for trying to help{START of RANT} but i know they(honda engineers) put a relay in there for a reason, and not just to **** me off. knowing this i asked for information on how it worked so i could modify MY car the way I want. Please dont tell me what you would or wouldnt do to YOUR car when i ask for information on MY car. {END of RANT} other than that thanks for the info about resoldering the relay .......
 
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Old 06-12-2009 | 08:05 PM
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Originally Posted by Riqand
#3 is 12v power going out to Injectors and ECU and #4 is 12v power feeding straight to #8 when the key is turned to START. I think i have this figured out now. #8 is an ECU controled ground. and RonJ thank you for the really informative link that showed me exactly what i wanted to know. MK378 thanks for trying to help{START of RANT} but i know they(honda engineers) put a relay in there for a reason, and not just to **** me off. knowing this i asked for information on how it worked so i could modify MY car the way I want. Please dont tell me what you would or wouldnt do to YOUR car when i ask for information on MY car. {END of RANT} other than that thanks for the info about resoldering the relay .......
Wow, way to be a complete ******* about it. He was just trying to prevent you from doing something you might regret in the future. How the hell was he suppose to know you don't care?

You could have just said "I am already aware of that but it doesn't matter to me, thanks for the concern though."
 

Last edited by trustdestruction; 06-12-2009 at 08:08 PM.
  #6  
Old 06-12-2009 | 08:15 PM
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Originally Posted by trustdestruction
Wow, way to be a complete ******* about it. He was just trying to prevent you from doing something you might regret in the future. How the hell was he suppose to know you don't care?

You could have just said "I am already aware of that but it doesn't matter to me, thanks for the concern though."
 
  #7  
Old 06-12-2009 | 09:15 PM
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ya i was a little pissy about it wasnt in greatest mood ........just hit a nerve.....i apoligize

hindsight being as it is ur right i should have said soemthing else ......like........I am already aware of that but it doesn't matter to me, thanks for the concern though. again sorry i was such an *** about it im a little cooled off now an regret my harsh words ........anyway didnt mean to come across as a complete douche
 
  #8  
Old 06-17-2009 | 02:56 PM
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If anyone was curious on how to successfully bypass the PITA Main Relay i would be willing to post my wiring diagram of what I did to remove the relay and rewire the harness to sucessfully work with two toggle switches.........very simple and easy workaround. And no more need to replace an $80 part when it fails...cause it WILL fail. Just shoot me a PM


PS I am still sorry about bein such an A$$ the other day .....
 
  #9  
Old 06-17-2009 | 02:59 PM
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I'm not going to do it nor do I recommend it to anyone except for maybe track only purposes and if they're aware of the side effects...


but yea i'd be very interested in seeing how you did it.




P.S. when they fail it's usually just weak soldering and you can pop the cover off and fix it in 5 minutes.
 
  #10  
Old 06-18-2009 | 05:19 AM
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Ill post my handrawn diagram up later today .......gotta let it dry out ....left the windows down last night, and now i have a swimming pool for a car.
 


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