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1995 EX Won't start, Main relay OK, no power to fuel pump

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  #11  
Old 01-05-2013, 10:15 AM
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When you turn keyswitch to On position, the fuel pump should come on and run for 2-3 secs and cut off. You can hear easily under quiet conditions, a buzz from the fuel tank. Is this happening each time keyswitch is turned to On? If yes, fuel pressure is likely good and problem lies elsewhere.

good luck
 
  #12  
Old 01-05-2013, 11:13 AM
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No power to fuel pump. I replaced the fuel filter and it drove one day fine, but the next day it started taking longer and longer before the check engine light would go off each time I cranked it. Sometimes it would take 15 seconds or more, then I would hear the pump and a click under the dash. Then I smelled smoke when I turned the key over (not turning the engine over, I just put key in start postion) From that moment on, check engine light stopped going off, no matter how long I wait.
 
  #13  
Old 01-05-2013, 11:23 AM
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Potential wiring fault or faulty MFR. The MFR relays get's too hot to touch when closed. I could imagine a relay shorting out easily. ECM is looking for relay to close, hence it waits for some time.

You can "hot wire" the relay by jumpering power from inlet-outlet on the relay. I did this to test fuel pump and found my fuel pump was not starting until I hammered the pump w/ repeated on/off/on.... See OEM manual wiring diagram to understand which contacts to jumper.

Suggest removing MFR and inspecting for burnt coil or damaged parts.

good luck
 
  #14  
Old 01-05-2013, 07:18 PM
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Guess I have to keep looking. I checked all ECM and fuel pump fuses, all ok.
(At least they look solid) Checked ground at fuel pump, cleaned re-tightened. Checked wire that MFR plugs into, had power at 1 & 2 pins. Old MFR, new MFR, it doesn't matter, no power to fuel pump. I doubt I bought a bad one.
I'm thinking the key to solving this is, the problem came on slowly, not all at once).
PaHonda said my D4 flashing code 14 was ECM related possibly, is there a way to test ECM to see if it's causing this, or do I need to test everything else first?
 
  #15  
Old 01-06-2013, 09:33 AM
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You could try hot-wiring MFR as I suggested. If ECM is disabling MFR, then bypassing MFR might allow engine to start. ECM may deny injectors or spark also, so this is not a for-sure check.

Have you checked continuity of wires from MFR to fuel pump connector? An open in the wiring would cause your problem.

good luck
 
  #16  
Old 01-06-2013, 12:04 PM
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Originally Posted by TexasHonda
See OEM manual wiring diagram to understand which contacts to jumper.
X2. Also see the factory service manual for an excellent MFR/fuel pump/ECM diagnosis procedure for fuel related no-starts.
 
  #17  
Old 01-13-2013, 03:03 PM
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Thanks for the help, Texashonda and guys this is what I did: Jumped from battery (7) pin in MFR connector to (4) wire to fuel pump, heard noise from rear of car, pump and wires seems OK.
Got service manual, page 11-96, did test of ground in MFR connector , OK, voltage to battery, OK, ignition voltage OK, starter voltage OK, the next page says "connect the test harness between the ECM and connectors". I don't have one of those. Should I find one , or send car to someone, or just replace ECM. Remember I have a code 14 from blinking D4 , no power to fuel pump when starting, a new Main Fuel Relay and smelled a slight smoke odor when turning key over to try to crank last time.
 

Last edited by Malcontent; 01-13-2013 at 03:19 PM.
  #18  
Old 01-13-2013, 03:32 PM
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You can do the step by checking continuity (open/closed) between terminal 1 and the A7 pin buy just unplugging the A connector from the ECU. That is the grn/blk wire between the MFR and the ECU.

For the last steps, you can backprobe pins A7, A23, A25, and B1. Here is a good image of back probing a connector. You would use a sewing needle and insert the needle between the rubber seal and the plastic connector, so you don't damage the rubber seal. I hope this makes sense.

 
  #19  
Old 05-29-2013, 03:32 PM
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OK, I have been driving another car but need to get this one going.
Instead of back probing I was thinking of finding the computer and inspecting it for damage or burn marks first. I pulled back carpet and saw how many bolts I needed to remove and quit for the day. I did get the garbage out of it, left the doors open a while. Later that day I decided to put it in neutral and push it back so I could cut the grass, when I did I turned the key over and varoom it cranked!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I drove it around town and added fresh gas. Next day, no crank. Arrrgh!
I'm wondering if cleaning the car, and leaving the carpet back away from the computer helped to dry out something maybe, making it able to start.
Last night I went out and , put key in and turned to start, listened for fuel pump. After about a minute, the fuel pump came on and the check engine light went off, and it cranked fine. This is with a new main fuel relay.
Is it sounding more like the computer is to blame than before or does this new info not help much.
 
  #20  
Old 05-30-2013, 09:18 AM
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Tried again last night, turned key to start, in about ten seconds D4 started flashing. Then after about 45 seconds the fuel pump came on. D4 kept flashing as the car cranked and ran. Turned it off , removed key, put key back in, tried again, this time D4 didn't flash and it took about 5 seconds before fuel pump came on. Repeated it again, it went the same way, D4 not flashing.
Any Ideas?
 


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