FAQ: Main Relay - Car Not Starting
Thread Starter
lots and lots of fail
Joined: Dec 1999
Posts: 23,004
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From: Deeeeeeeeeeeeeeetroit
FAQ: Main Relay - Car Not Starting
Having trouble starting your car when it's in the sun or at odd times? It could very well be the 'Main Fuel PGM-FI Relay'. It's a very common problem on all generations of Accords.
PURPOSE: Supplies power to the Engine Control Module (ECM) , injectors and the fuel pump.
OPERATION: The main relay actually contains two individual relays.
One relay is energized whenever the ignition is on, and it supplies the battery voltage to the ECM, power to the injectors, and power to the second relay.
The second relay is energized for 2 seconds when the ignition is switched on before starting, and when the engine is running, to supply power to the fuel pump.
PURPOSE: Supplies power to the Engine Control Module (ECM) , injectors and the fuel pump.
OPERATION: The main relay actually contains two individual relays.
One relay is energized whenever the ignition is on, and it supplies the battery voltage to the ECM, power to the injectors, and power to the second relay.
The second relay is energized for 2 seconds when the ignition is switched on before starting, and when the engine is running, to supply power to the fuel pump.
1990-1993 Accord
1994-1997 Accord
1998-2002 Accord:
Registered User
Joined: May 2005
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Thread Starter
lots and lots of fail
Joined: Dec 1999
Posts: 23,004
Likes: 1
From: Deeeeeeeeeeeeeeetroit
A neat diagnostic trick:
The Main Relay will click three times during the starting process. When problems arise, one of those clicks (usually the third) is missing, making those clicks a handy diagnostics tool. If you consistently hear/feel all three clicks, the Relay is fine. DO NOT REPLACE IT.
Turn ignition to ON (but not to START): Click 1
Check Engine light goes off: Click 2
You now turn the key to START: Click 3
The Main Relay will click three times during the starting process. When problems arise, one of those clicks (usually the third) is missing, making those clicks a handy diagnostics tool. If you consistently hear/feel all three clicks, the Relay is fine. DO NOT REPLACE IT.
Turn ignition to ON (but not to START): Click 1
Check Engine light goes off: Click 2
You now turn the key to START: Click 3
Member
Joined: Sep 2005
Posts: 58
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From: Ponce, Puerto Rico
Great post. The same thing happened to me when I bought my 2000 V6 coupe. The bitch just wouldn't start in the morning and I almost sold the car, but my Honda mechanic helped me out big time. Now I keep the old relay in the trunk as a reminder how something so small and cheap can cause so many problems. This should be a sticky!
h:
Junior Member
Joined: Jan 2006
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Will this cause a No crank problem?
My wifes 95 Accord ex is starting to have issues starting, but no crank is the problem, new battery, problem is not going away. Intermittent, car starts normally most of the time.
Never "hard" to start, just you get starter and boom it starts right up or turn key and nothing.......
My wifes 95 Accord ex is starting to have issues starting, but no crank is the problem, new battery, problem is not going away. Intermittent, car starts normally most of the time.
Never "hard" to start, just you get starter and boom it starts right up or turn key and nothing.......
