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Louis

Low voltage to fuel pump

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Hey guys, I'm needing some help with my 2007 Honda rancher trx420fm. I'm getting low voltage (3.9v) going to my fuel pump. I've replaced the fuel pump itself and the relay twice. It has a fairly new battery reading over 12v. I've ran a wire from the battery straight to the fuel pump and the pump will run but still not start. I've also used a jumper in several places on the wiring harness and nothing. Would the voltage regulator have any affect like this?

Edited by Louis

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first, get rid of the china fuel pump ( yes..i know its a ebay spec from other site ), then we'll take it from there. no, i do not believe your reg/rec has anything to do with not getting 12 volts to the fuel pump. this sounds like a relay or fuse issue to me.

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i wish mel was around, or toodeep, they could give you more info on that stupid bank angle sensor !.

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its late here, most members wont be online until later today/tonight, but i bet you get help !.

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hey louis...the voltage on your battery should be above   12.4 better yet close to 13.1 if fully charged....i didn't mean you had the wrong battery, just that your batt. is not good enough...

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One more thing, be careful about putting a car charger on the atv battery......it might be too much for it....😀

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I would start with checking the wiring from the fuel pump to the fuel pump relay (brown wire). If it ohms good and your getting low voltage out of the relay then we can move on to the components. If the bank angle sensor is in any question at all it can be bypassed with a jumper wire to the 2 outer terminals on the connector (wire harness side).

IMG_20150527_175925980.jpg

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Hi: Check the voltage on the Ign. fuse (10 amp) -- leave the fuse in place -- on the top of the fuse you will see two small gray dots -- test the voltage on each dot with the key on for 12 VDC. Then go to the Ign. coil and test the voltage there on the Bl/R wire with the key on.

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I appreciate the replies. I ohmed the wire between fuel pump and harness connector then from the harness connector to the relay and both wires ohmed good. I then ohmed each fuse on the metal tabs on top and they all ohmed good. The battery shows 12.8v. I used a jumper on the angle sensor and still nothing. I didnt have time to check ignition coil and voltage through fuses but will tomorrow. I work nights at the moment 

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Hi: Okay -- Check the voltage on the top of the Ign. fuse -- I had to replace a couple of key switches on the 420's lately.

Edited by Melatv
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Ok, I'll do that tomorrow and I'll let you know what it reads

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Shadetree, I agree. I appreciate you referring me over

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I checked the voltage on the ignition fuse and ignition coil. Both read 13v. 

 

Edited by Louis

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19 minutes ago, Louis said:

I checked the voltage on the ignition fuse and ignition coil. Both read 13v. 

 

is there a way you can jump the fuel pump relay, long enough to see if you get 12 volts to pump ?.

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I haven't actually checked the voltage that way but I did run a wire from the battery to the fuel pump and the pump did run but it still wouldn't start up

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2 minutes ago, Louis said:

I haven't actually checked the voltage that way but I did run a wire from the battery to the fuel pump and the pump did run but it still wouldn't start up

neutral light on the dash ?. getting spark at spark plug ?.

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Wait, I did jump the fuel relay to the pump and it didnt do anything. I didnt check voltage though. Yes neutral light is on. I checked voltage inside spark plug wire and showed 13v

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12 minutes ago, Louis said:

Wait, I did jump the fuel relay to the pump and it didnt do anything. I didnt check voltage though. Yes neutral light is on. I checked voltage inside spark plug wire and showed 13v

you don't get 13v in boot wire bro, least not 13v !..lol

 

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with spark plug in boot, laid on engine, neutral light on dash, cranking it over, watch spark plug, get spark ?.

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I put the volt meter in the boot with key on and it showed about 13v lol. I tried a while back to get it to spark on frame with the spark plug in and was not getting a spark. I thought it had something to do with the fuel pump not getting voltage too lol

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Hi: is the Run switch in the center position ? If so unplug the PCM and check for 12 VCD on the Bl/W wire on the connector. Also have you tried a new spark plug?

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Yes, run switch is on center. It wont even turn over otherwise. Ok, I'll check that tomorrow after work. I haven't tried a new spark plug but I will do that too. Thank you 

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4 hours ago, Louis said:

I put the volt meter in the boot with key on and it showed about 13v lol. I tried a while back to get it to spark on frame with the spark plug in and was not getting a spark. I thought it had something to do with the fuel pump not getting voltage too lol

lay spark plug on engine for ground..not frame.

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I believe I tried the engine too but I'll buy a new spark plug and try again

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