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BradBoltz

87 350D starting issue

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I have an issue with my 350D it only stays running as long as I hold the start button down I can rev it and all but can't drive it I replaced the battery and starter relay and ignition coil and still does the same thing and I have on order a cdi and pulse generator also I have an aftermarket Mr gasket fuel pump hooked up from the battery to the ignition switch can anyone give any suggestions on what it could be wrong or point me in a direction....thanks

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Welcome to the forum!

 

What year & model is your TRX350?

 

The fuel pump relay cuts the ignition on and off in normal use, so I suspect that you may have bypassed that relay? Or disconnected it? Does the Neutral light work as expected? Wiring harnesses in good condition, no splices? Please list the aftermarket parts that are on it too...?

 

Thanks

 

EDIT: Nevermind the year question... I see you mentioned that it is an 87. Is it a TRX350A or a TRX350D?

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It's the 350D everything worked on it I ride it daily then it just stopped like it ran out of gas I filled the tank and now it only stays running as long as I hold the start button in the neutral light works fine the only aftermarket I put on is a Mr gasket fuel pump 

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You'll probably need to hook that fuel pump up right. I suspect that the fuel pump relay is shutting the ignition down because the pump load is out-of-circuit now. My best advice is replace the failed OEM pump with a new OEM pump. Aftermarket pumps don't get ya very far on TRX350s, and are certainly not worth modifying the wiring harnesses to make them work. You can check that fuel pump relay using a multimeter. Its covered in the service manual, which you can download for free from the link on the menubar.

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Hi: Have you got the 2 small red wires on the solenoid starter on the stud with the cable going to the battery?

350D.jpg

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I have the 2 red wires hooked up I ran this ATV all summer long with the aftermarket fuel pump hooked up direct and all ran good it just stopped running is there a way to bypass the fuel cutoff relay and also does that relay effect the ignition in anyway 

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20 minutes ago, BradBoltz said:

I have the 2 red wires hooked up I ran this ATV all summer long with the aftermarket fuel pump hooked up direct and all ran good it just stopped running is there a way to bypass the fuel cutoff relay and also does that relay effect the ignition in anyway 

There’s no good way to bypass it. You risk damaging other components.

 

you have the service manual?

if it ran well all summer and now only runs if you hold start switch? tells me electrical.


this model is a one year type of ignition system—there are two other CDI/ignition systems. CDI can fail, but wires can break, connections can become intermittent. There’s a lot that can trip up here.  I recommend you start with all OEM components, 
 

Download the service manual it has diagnostic diagram you need to follow. 

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I tested the start button and the run switch they tested good I also tested the plugs on the harness side of the cdi like the manual says they all tested good not sure where to go next I was thinking the fuel cut off relay cause figured if that went bad it would think it's rolled over and would not let it run been trying to get the cover off it to there is only a ground and one wire going to the battery and one going to cdi from what I see in the diagram was going to try and trick the cut off into thinking it's not rolled over to see if that is what the problem is 

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start with an oem fuel pump, check/replace fuel cut-off relay. I read your other thread from old site, ( which is why your here I hope ? ..lol ), holding the start switch to keep it running tells me the fuel cut-off relay or fuel pump is not getting power unless its turning over. the oem pump should only work when the crank is turning over. simple test: spray some starting fluid ( short, small burst ! ) into the back side of carb, if it cranks this way ?, then its a fuel issue. if it does not '' crank over '' this way ?, then its a compression issue ( which I don't think ? ) it is ?. my money says its a fuel issue, spec if you do not have an oem fuel pump on it :-).

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1 minute ago, BradBoltz said:

I tested the start button and the run switch they tested good I also tested the plugs on the harness side of the cdi like the manual says they all tested good not sure where to go next I was thinking the fuel cut off relay cause figured if that went bad it would think it's rolled over and would not let it run been trying to get the cover off it to there is only a ground and one wire going to the battery and one going to cdi from what I see in the diagram was going to try and trick the cut off into thinking it's not rolled over to see if that is what the problem is 

the fuel cut-off does not work like a bank angle sensor, the fue cut-off relay works off back pressure from the carb, as well as crank position from the pick up coil, through the c.d.i. does the oil light come on when you turn the key on, then shut back off after a couple sec's ?, if not ?, then the fan control unit is bad, but this would mean its not firing the spark plug, which I dont think thats your problem here.

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5 hours ago, BradBoltz said:

I have the 2 red wires hooked up I ran this ATV all summer long with the aftermarket fuel pump hooked up direct and all ran good it just stopped running is there a way to bypass the fuel cutoff relay and also does that relay effect the ignition in anyway 

 

I must correct my earlier statement. The answer is no, on the '87 TRX350D the ignition is not ever interrupted, except by the ignition switch and handlebars kill switch. That year and model ignition and fuel systems are one of a kind, 87 350D only.

 

On '88 and later models the CDI ignition included what Honda termed a "Revolution Research" line, which shut down the fuel pump relay and the ignition when the motor stopped turning, but your '87 350D does not have that feature.

 

The '87 and up 350D fuel pump relay operates whenever the ignition switch is turned on (the 86 & 87 TRX350A models fuel pump relay engages while the motor is cranking over by the starter). If your pump were OEM and connected properly you would hear the fuel pump run for a couple seconds until it built up fuel pressure, then the pump would shut off via its integrated pressure switch... but the pump relay itself remains engaged as long as the ignition is turned on.

 

So, nevermind testing your fuel pump relay at this point, because your pump is wired up directly to the battery.

 

@Melatv and @Goober provided the best advice so far. If both of those small wires are connected to the positive battery terminal, then check (& replace if necessary) the main fuse and the ignition fuse. You should test for voltage on both sides of those fuses while the ignition switch is on in case a fuse looks good... but is not.

 

Then you'll need to test both positive voltage circuits exiting your ignition switch and test your kill switch. You may need to clean and reattach the frame ground for the wiring harness located under the seat as well.

 

Then take the cover off from the fuel pump relay and harness junction box. Inside you'll find a round connector for the regulator/rectifier. Unplug that and inspect the terminals in both connector halves for corrosion or damage from overheating. Shine up the contacts and Dielectric grease them before plugging them back together.

 

If it still does not work get back with us so we can help you find the problem.

 

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Does the fuel pump cycle and is there fire at the plug? OEM cdi and do the numbers match (little sticker on the connector)?

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I'd replace that pump with a factory one and check your wiring, I don't have the manual link but I'd ask and someone else may have the test procedure for the CDI to see if it's really bad. 

 

Ya said you had to hold the start button to keep it running, a test you can do hold the button, and tap LIGHTLY but repeatedly on the CDI if ya can get to it fast enough after letting off the button, it should stay running on its own. If not by by CDI. That's just my opinion though.

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On 12/25/2019 at 10:21 PM, BradBoltz said:

I am at a point where I think it's the cdi does anyone have that there willing to sell or know where I can get one

 

Your motor runs while holding the start button down so the CDI is working fine. Your issue is a much simpler electrical one. You do need to replace that aftermarket fuel pump with an OEM pump and connect it back up as it originally was though. Take the cover off from the fuel pump relay and connector box so you can troubleshoot it. We can go step by step diagnosis with ya once ya get everything put back to OEM.

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Just a quick update got the new oem cdi box and it started up and ran without holding the start  button in

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Thanks for following up and letting us know how you fixed it!

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Ok y'all I am stumped no spark issue now and I check the ignition coil primary and secondary and it checks good I check it at the co box and it measures high like as in 3.5 ohms at cdi according to the book it's suppose to be .1 or .2 ohms what could be the issue 

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The lowest I got for testing the ohms for the ignition coil at the plug for the cdi was .7 ohms the pulse generator measures within the 300 to 360 I get battery volts at the cdi plug for the stop switch the ignition coil itself measures within spec according to the book my only issue is no spark after I ran it on a new oem  cdi for a few days could it be a ground issue 

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First question... does it have a battery in good condition in it? How many volts does the battery measure at rest, with the ignition switch off?

Do you see any evidence of overcharging? Are there any light bulbs, headlight, tail light etc., blown?

 

Next question, are there any china parts (non-OEM) on the bike besides the fuel pump? Are the ignition switch and ignition coil OEM?

 

 

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I woke up the next morning went out and tried to start it and it started right up and has been running not sure what happened can it be that there is some sort of self reset on the cdi or something 

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