Hi.
I have a 1994 Accord Wagon 4 speed auto F22B1 engine.
Today we have managed to trace a no power to fuel pump to the Park and Neutral switch. By moving it out of Park the power is restored to the pump. Unfortunately I don’t have a wiring diagram to try and work out what’s happening. We used a good bit of electrical clean and lube on it and there is no visible signs of breakdown it appears to be very well made.

So I’m seeking some direction as to what else may be causing this and a wiring diagram.

So far I have replaced the Main Relay, fuel filter and the fuel pump. Ignition switch doesn’t fault.
Best wishes
Katie-Joy in Australia

 

It may possibly be due to a faulty ECM.

The ECM needs to send a ground signal via the Grn/Blk wire to the main relay (from ECM terminal pin A7 to main relay terminal pin 1) in order for the fuel pump relay to energize and close, which will then supply power to the fuel pump. (The main relay has two individual relays inside, they are both normally open type relays.)

It sounds like when the Park/Neutral input from the A/T gear position switch via the Lt Grn wire sends a ground signal to ECM terminal pin B7, it causes the ECM to not send a ground signal from ECM pin A7 to the main relay.

You could try temporarily grounding main relay terminal pin 1 with a jumper wire to body ground and see if it works.

 

Many thank Tech 8 its 1:36 am hear so will check out when the sun comes up
Best wishes
Katie-Joy

 

If the shifter cable is out of adjustment it may put the trans in gear but not have the switch in the correct position.
Also it should not kill power to the pump. There should only be the starter interlock on P and N to prevent starting the car in gear(R D4 D3 D2 D1).

 

The Park/Neutral input from the Lt Grn wire to the ECM is separate circuit wiring than the starter system. The Park/Neutral input lets the ECM know the transmission is in Park or Neutral; thereby the ECM may control the idle via a Blu/Blk wire (IAC valve control wire providing ground) from ECM pin A9 to the IAC valve.

 

Hi Tech8.
What started out as an intermittent fault now seems to accrue all the time. I tried your suggestion (try temporarily grounding main relay terminal pin 1 with a jumper wire to body ground and see if it works) unfortunately it didn’t, it was working when I moved from park to neutral but that temporary fix no longer works.
If I’m understanding you this point’s to ECM. Is there a way of checking it?
If it needs replacing have you any idea of cost, does it need programming and any other complications I should know about.

Any recommendations would be appreciated this 70yr old is getting a might stressed. This problem started 12 months ago and has cost $770.00 so far.
Thank you for your assistance
Katie-Joy

 

It may or may not be related to the ECM. There is no direct way to test whether the ECM is faulty, other than swapping a good known ECM. In U.S., the 94 Accords do not have the Immobilizer and does not require programming; I would believe that is the same for your Australian model. I would not know the costs to obtain parts in Australia.

You can always open up the ECM and visually check for damaged components.

1. Is the Fuel Pump still not getting power?
2. If so, since temporarily applying ground to the Main Relay terminal no. 1 didn’t change anything, check the following. Some of the checks will require backprobing the wire terminals with the electrical connector still plugged into the Main Relay.

• At the Main Relay terminal no. 7 White/Grn wire, check for battery power (+). This should be Hot all the time.
• At the Main Relay terminal no. 5 Red/Wht wire, check for battery power (+) when the ignition is in ON or START.
• At Main Relay terminal no. 3 Blk wire, check for continuity to body ground.
• At Main Relay terminal no. 2 Blu/Red wire, check for battery power (+) when the ignition is in START.

Any of the above not working properly, or if there is no ground signal from the ECM to Main Relay terminal no. 1 can cause the fuel pump relay to not provide power (+) through the main relay’s terminal no. 4 Blk/Yel wire to the fuel pump.

 

Tech8
Thank you

 

Tech8
I forgot to mention that D4 on the dash board is flashing I'm not sure if that is a code
Thank you
Katie-Joy

 

You may want to retrieve the transmission trouble code(s). Normally, you would jumper a blue 2P Service Check Connector (for U.S. models, located under the passenger dash) to retrieve the transmission trouble code by counting the D4 flashes.

 

Thank you.