no fuel & ecm not talking to main relay
#1
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no fuel & ecm not talking to main relay
Have a 2k Accord that we can crank and get spark to the spark plug but no fuel. Ran diagnostics but lead toward path of something in security system. Replaced fuel pump (no resolution), replaced ignition switch (no resolution), and even reset ECM. Best we can tell is that the ECM is not activating the main relay. it's getting power and it grounded. Trying to avoid R&R computer just to see if that is it.
any other suggestions?
any other suggestions?
#3
RE: no fuel & ecm not talking to main relay
The Main Fuel Relay (MFR) has been a persistent problem for Accords since the 90 Accord at least. It has nothing to do w/ ECM, but rather is a failure of solder joints on the MFR.
One way to know for sure is to "hot wire" the MFR (jumper the circuit board) to avoid the ECM automatic shut-off after 3 seconds w/ keyswitch ON, but no start. If you still have problem, you can rule out both MFR and ECM as source of the problem. ECM should keep MFR grounded as long as the keyswitch is in Start position and when engine is running in ON, and only disable MFR if keyswitch is ON and engine is not turning.
I rigged a "tell-tale" light to my MFR fuel pump power supply to understand why I was getting an intermittent no-start for what seemed to be a bad MFR, but could not be fixed w/ a replacement MFR. Light finally revealed the fuel pump on occasion "sticks" after an extended shutdown and won't kick off. Repeated "hits" w/ my hard-wired MFR finally got it to start. I'm now ordering on a new fuel pump to install.
good luck
One way to know for sure is to "hot wire" the MFR (jumper the circuit board) to avoid the ECM automatic shut-off after 3 seconds w/ keyswitch ON, but no start. If you still have problem, you can rule out both MFR and ECM as source of the problem. ECM should keep MFR grounded as long as the keyswitch is in Start position and when engine is running in ON, and only disable MFR if keyswitch is ON and engine is not turning.
I rigged a "tell-tale" light to my MFR fuel pump power supply to understand why I was getting an intermittent no-start for what seemed to be a bad MFR, but could not be fixed w/ a replacement MFR. Light finally revealed the fuel pump on occasion "sticks" after an extended shutdown and won't kick off. Repeated "hits" w/ my hard-wired MFR finally got it to start. I'm now ordering on a new fuel pump to install.
good luck
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