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Discussion Starter · #1 ·
First I will say hello from Florida and this looks to be a great site!!

I have a problem with a 07 TRX420FE:

The unit was trashed and blown to the point of needing a complete engine rebuild. When we received the unit it was taken apart (top end only) by a different dealer, so we never knew what was functioning or not functioning (we do know it must have ran for the amount of damage done engine wise). We rebuilt the engine and reinstalled all plugs to the proper connections and have rechecked more than I care to mention. The unit cranks fine but there is no spark, no power to the fuel pump, and the electric shift does not respond. The MIL comes on when the ignition is on only for a few seconds. The gear position indicator is continuously flashing ("-") and is the same rapid flash pattern. We have checked all the tests that can be done with a multi-meter and did find that the orange wire (A21) on the 33P and 21P don't have resistance. So with that test, the manual tells us to replace the PCM/ECM. I wanted to make sure that is the problem or if a different part may cause that test to possibly fail.

I did notice that the dealer did cut out the green 14P handle bar connector and soldered the wires direct with no protection against water. Is it possible that if water was to short one or all, would it damage the PCM/ECM?

Just wondering if anyone has had the same symptoms and what the resolution was. We do have the service manual and as mentioned have done test after test. I know I will work it all out, I Just wanted to pick a few brains before I order parts for no reason. I'm sure I have not mentioned all the tests we have done or things we checked, so please ask if I checked ________ and I will reply as to if it was tested or checked.

Again the symptoms are: Cranks fine, No spark, No fuel pump power, Electric shift does not respond and The gear position indicator is continuously flashing ("-") and is the same rapid flash pattern.

Thanks to everyone and sorry for the short intro.
 

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It sounds like you have tested all the circuits. The issue with the bare wire could be a problem but I would think that putting some tape or tubing on it would solve any grounding problem and keep water out. I would trust the manual and replace the indicated parts. If you didn't get the timing correct when you reassembled the engine it should still spark but out of time. Good luck.
 

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If water or anything else, shorts a PCM circuit out, yes it can damage the PCM and probably did. The loss of spark, power to the fuel pump, and loss of electric shift all at one time, sounds like a PCM problem. Remember if it did this, make sure you fix the shorted circuit before you replace the PCM. If you don't, when you plug the new PCM in, it will be damaged also. It would be a good ideal to check all the circuits going to the PCM, and if I read correctly, you already have. I, personally, haven't had this problem with an ATV, but I have dealt with the same problem on automobiles. When you go through deep water with a FI vehicle and it gets water in a sensor or circuit and shorts out, it will fry that circuit in the PCM. The PCM needs to be pulled, the shorted circuit fixed, and all the other circuits need to be tested at the pins on the plug where the PCM plugs in. You have to get a spec. sheet from the dealer and test each pin in the plug for the correct readings listed on the spec. sheet, before you plug the new PCM in. If you don't, it will just fry the new PCM. This is the reason why parts stores won't warranty electrical components. If the circuit is bad and you don't repair it, before plugging the new component in, it will fry the new component.
 

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Discussion Starter · #4 ·
Thanks guys,

The short in the wiring may or may not have been short. I meant that the other dealer removed the connector and soldered the wires. They did a good job but my issue is they did not use an epoxy type heat shrink tubing on each wire so water can penetrate the repairs. So when the wires are all bundled in the loom, and although the tubing would protect a direct wire to wire short, it may not protect a water type short as if going through deep water (the reason why the engine needed a rebuild). Because of the multiple symptoms it leads me to believe that there is more to the story than I know at the moment.

Will a bank angle sensor disable the electronic shifting? I wouldn't think so, but I have never tried it so I thought I would ask.
 

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didnt read all the post so sorry if someone already said this. it needs to have the HDS pluged into it and run a few tests. i have seen several that did this and the HDS said it could not communicate with atv, replaced pcm and woked fine.
 

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from the sound's of it..your cdi is toast..as stated..check all your wire connections before you plug a new cdi in..or you will fry the new one soon as you plug it in..and turn the key...also...when checking for spark..ALWAYS...ALWAYS GROUND SPARK PLUG TO JUG..or a very good ground...if you don't...you can fry the cdi instantly !!..make sure to ground spark plug !
 

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Any status on the fix yet?
I just had this happen on a 2008 420 this weekend. Few water crossings at floorboard level but bike ran fine. shut it down for a break and it wouldn't re-start. Bike cranks but no spark or fuel pump and also has the flashing "-". We pulled all connections and everything was dry and clean. All fused checked good with a meter.

Looking for fix.
 

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having same issue put bike away last fall in heated shop went to move no spark no fuel pump and and shift light constant flash check all connections any help would be apreciated cranks well and do have neutral light kill switch on etc
 

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My 07 420 is doing the same thing. Only i have a manual shift so the only light that comes on is neutral light when you turn on. It cranks fine but no spark and no fuel pump buzz. All fuses have been checked and battery is good. Has anyone found out what this is?
 

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07 420 manual shift turns over but no spark or fuel

My 07 420 is doing the same thing. Only i have a manual shift so the only light that comes on is neutral light when you turn on. It cranks fine but no spark and no fuel pump buzz. All fuses have been checked and battery is good. Has anyone found out what this is?
 

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My 07 420 is doing the same thing. Only i have a manual shift so the only light that comes on is neutral light when you turn on. It cranks fine but no spark and no fuel pump buzz. All fuses have been checked and battery is good. Has anyone found out what this is?
I would be checking the reg/rec, the stator, as both of these control fire to the spark plug coil, which leads to the spark plug. you can also try another spark plug. if it's not any of these ?..then I would say your ecm/c.d.i. is bad.
 
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