Main relay, Fuel pump relay.. same thing????
The fuel pump relay is integrated into the main relay. The main relay is actually two relays in one, one that supplies power to the ECM, and the other supplies power to the injectors, fuel pump, etc.. once the ECM sends the signal.
later,
Jared
later,
Jared
Thread Starter
Honda-Tech Member
Joined: Mar 2001
Posts: 478
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From: Hamilton, Ontario, Canada
Thanks!!
I called the local parts store and they didn't know what the hell I was talking about when I asked for a Main relay for my car. They kept sugesting a fuel pump relay.
I called a Honda dealer and he knew right away and I picked it up and installed it a few minutes ago.
Car seems to be starting fine now... but the problem was intermittent so I can't be totally happy until it works for a few more days at least.
I called the local parts store and they didn't know what the hell I was talking about when I asked for a Main relay for my car. They kept sugesting a fuel pump relay.
I called a Honda dealer and he knew right away and I picked it up and installed it a few minutes ago.
Car seems to be starting fine now... but the problem was intermittent so I can't be totally happy until it works for a few more days at least.
It seems from the problems on this board that when the Honda main relay's get around 9-10 years old they are no good anymore...
I have seen a low percentage of main relays that were actually fixable w/o replacement..
I have seen main relays develop a "cold soldered joint" on the switch contact..
Its always the same solder joint too!
If you have one of these, soldering that joint could put a temporary band-aid on the problem, seems they all just go bad eventually... I might have one of these in my tool box, if so I will take a pic and post..
[Modified by BreakStuff, 2:32 AM 8/30/2001]
I have seen main relays develop a "cold soldered joint" on the switch contact..
Its always the same solder joint too!
If you have one of these, soldering that joint could put a temporary band-aid on the problem, seems they all just go bad eventually... I might have one of these in my tool box, if so I will take a pic and post..
[Modified by BreakStuff, 2:32 AM 8/30/2001]
Yeah, 8 years is pretty much the life expectancy of a main relay, and the problem is, you could be really lost unless you knew that since most relays will cause the computer to set a code 16 when cranking since there is no voltage on the ground side of the injector to the ECM since the relay isn't supplying any.
I never trust them damn ecu's! 
If the car is gonna "starve" for fuel it will most definately throw a code 16..
Fuel Pump, clogged fuel filters, bad injector(s) ,main relay.. I've been burned before by codes and only resort to them in an intermittent problem..
for example.. for reasons unknown, Izusu engineers would place multiple OBDII sensors in a "parallel circuit".. If a 5v reference signal of a sensor failed, only the first sensor in that circuit would report a problem, meaning the reporting sensor may be in normal working order, and the problem may be elsewhere in that circuit... what a blast diagnosing these vehicles!
God Bless you Jared upon being a Nissan Tech..
I once put a headgasket on a 96 Altima, took me about 2 days and a whole lot of words I didn't realize I had in my vocabulary!

If the car is gonna "starve" for fuel it will most definately throw a code 16..
Fuel Pump, clogged fuel filters, bad injector(s) ,main relay.. I've been burned before by codes and only resort to them in an intermittent problem..
for example.. for reasons unknown, Izusu engineers would place multiple OBDII sensors in a "parallel circuit".. If a 5v reference signal of a sensor failed, only the first sensor in that circuit would report a problem, meaning the reporting sensor may be in normal working order, and the problem may be elsewhere in that circuit... what a blast diagnosing these vehicles!
God Bless you Jared upon being a Nissan Tech..
I once put a headgasket on a 96 Altima, took me about 2 days and a whole lot of words I didn't realize I had in my vocabulary!
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