Starts and dies

Q&A about routine maintenance.
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2mike18
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#1 Post by 2mike18 »

Last season when I parked the quad it ran mint now I pulled it out drained the old gas put new gas in and checked the quick connects and fuel seems to flow good. Fuel filter seems good as well. Problem I have is when I start the quad it's runs maybe 1 second and dies. It will restart but will not continues to run. Any suggestions on what to check or clean ? I am confused here my yfz no prob runs great my dale seems to be upset and doesn't want to go play.

MX Quad Dad
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#2 Post by MX Quad Dad »

I got one here that did the same thing. Im not sure how long it sat because my son just bought it. it would fire then stall. it hada pod filter so i took it off and dribbled a littie gas down the intake until it stayed running. but it wouldn't take any throttle. it ended up being the relay in the air filter tray.

wistech
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#3 Post by wistech »

Starting and dying within a second everytime is symptom of only one injector firing. Its easy to tell which one it is just by unplugging one at a time. The one that doesnt change anything is the bad one. A sharp tap of a screwdriver handle works most of the time to break the pintle free. Just be sure to hit the body and not the connector. If it starts and runs but dies intemitantly (especially when revved ) thats usually the relay . Simply unpluggin it and tossing in the tool box is the fix for that. You only really need the relay for changing maps and hex codes to keep the ecu powered.

2mike18
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#4 Post by 2mike18 »

Thanks guys. I will try the injector trick tomorrow. I believe I have a spare or 2 just in case but I hope the tapping will be the fix.

MX Quad Dad
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#5 Post by MX Quad Dad »

QUOTE (Wistech @ May 5 2012, 09:47 PM) <{POST_SNAPBACK}>
Starting and dying within a second everytime is symptom of only one injector firing. Its easy to tell which one it is just by unplugging one at a time. The one that doesnt change anything is the bad one. A sharp tap of a screwdriver handle works most of the time to break the pintle free. Just be sure to hit the body and not the connector. If it starts and runs but dies intemitantly (especially when revved ) thats usually the relay . Simply unpluggin it and tossing in the tool box is the fix for that. You only really need the relay for changing maps and hex codes to keep the ecu powered.



Thats interesting and very possible Mine had a stuck injector and it worked loose when I was keeping it running.

The relay part is even more interesting. I don't think I ever seen it mentioned that the main reason for the relay was to down load. So if I ditch the relay, can I just hold the start button in to down load? Or maybe route the pigtail for the relay so I can plug it in without removeing the plastic?

Canniboomer
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#6 Post by Canniboomer »

I've never encountered any permanent need to remove the relay. But they certainly might need to be re-secured, or the female harness tangs re-tightened.
The relay socket is easily dissected by pulling out the white piece.
For so many machines using a direct intake nowadays, there is plenty of room to lift the relay off the floor of the ECU tray, and then INSULATE it -- and just forget about it.

As for the MAIN reason of a relay for programming?... I don't think we can draw that conclusion, since the non-programmable MC-500 used 2 relays on the ATV.

Note Cannondale Bulletin SB02-003 for the warning about diode damage risk, when not using the relay...

wistech
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#7 Post by wistech »

Injectors can stick right at the tip of the pintle from sitting for long periods without fuel in them or rotten fuel. Tapping on them will break the plunger loose most of the time . Then fresh fuel will dissolve the varnish as it runs . If it doesnt break free soaking the injectors in injector cleaner overnight should do the trick . Although tapping works most of the time.
If they do fire and it still runs lean and changing fuel settings doesnt make a difference then one of the spray holes might be plugged. In that case Id just get another set of injectors as cleaning them costs about as much as new ones.

As far as the relay . Do what you feel is right . Stalling quads on jumps , in the middle of nowhere or losing races was getting old. Removing them has done the trick for many years now with no failures so if we start blowing diodes maybe it would be something to look into. My brand new 02 speed had a bad relay from the first ride and it took years to figure out what caused the cold weather stall. So for reliabilty sake I just left them out. I guess if you really wanted to keep the circuit functioning you could just install a manual switch in to replace what the relay does . I did install a waterproof housing and connector using the internals from a stock relay because i could not find a replacement that had a diode and resistor in it like the stock one.

2mike18
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#8 Post by 2mike18 »

Update........It runs nicely again it was the left injector got it on first one tried. I figured no way am I that lucky so I pulled the airbox and throttle body off to look inside and sure enough that injector wasn't spraying. Thanks Wistech you know your dales very well.

MX Quad Dad
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#9 Post by MX Quad Dad »

I trust his findings and my relays will find a new home in the tool box until i forget what they were for and toss them.

Z4J
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#10 Post by Z4J »

Good input. Thank you.

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