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Discussion Starter · #1 ·
Hey guys,

My LTR will start and idle just fine and I can rev it right after I start it and it's fine. But after I take it on a quick spin, for say 5 minutes, it will randomly die if I try to idle. It will then not start back up. Takes a while until it will start. New fuel filter and new spark plug. Any thoughts? I did order a block off for the throttle advance just in case there is a problem there.
 

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Discussion Starter · #3 ·
No the lights don't flash. I'll have to test the fuel pressure. Thanks for the thought. Any other ideas that I should check when I get off of work tonight?

I have seen a coil fail due to heat and when it'd get warm it'd stop working. But it will burp every once in a while after it dies. Fuel pressure actually seems like a good place to go from here. I ordered a block off nut for the choke because I thought maybe when it warms up that is not allowing it to stay running, plus been wanting one as the cable is broken it appears anyway.
 

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Discussion Starter · #5 · (Edited)
I wonder if I set my idle wrong if that is bad, that is mainly what I meant. I'm going to have to order the gauge to check the pressure unfortunately. But I bet that is it. Might just order a compression checker while I am at it, been needing one of those anyway.

EDIT* Where can I find the gauge adapter I've checked around but can't find a part number?
 

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I thought I posted this yesterday

Sounds like the valves are tight, After it is warmed can you pull start it. still would check the valves.
 

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Discussion Starter · #8 ·
I haven't tried to pull start it. I work 2nd shift so whenever I do anything to the quad it's alone and there are no hills by me. But the valves should be good. Just did them. And checked them multiple times after rotating the crank.

Rode the quad today and it rides quite well, good idle and sounds fine on the top end side too, was actually trying to get it to die and not start so I could see if it sputtered or anything that might say fuel pressure. Didn't die on me today. There is still a problem though. It died yesterday and wouldn't start and it did it the last time. Fuel pressure is still where I am going with it.

Do you know the size of those high pressure fittings are? Going to order up a tee tonight so that I can check it. Couldn't find one around town. Was thinking 1/4" hose barb tee and then some high pressure line and a gauge.

Really am sorry to ask stupid questions if it seems that way. Really not a lot of info on here about a fuel pressure tester and the fitting size, have tried the search function. Also having trouble wrapping my head around running well and then just dying and not starting again. Usually is electric when that seems to happen. Fuel injection is new to me.
 

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Discussion Starter · #10 ·
Just a quick update. I am waiting on the fittings to test the fuel pressure. Got the line and gauge. Also got a compression tester that I am waiting on fittings for as well. Wanted to have a setup that would last and I got a nice winters liquid gauge for the compression tester. So I'll check fuel pressure and compression as quickly as possible.

Also took the quad out today. Love that thing. Rode it about 20 minutes today. It died after that and wouldn't restart. Didn't sputter and the idle didn't change. Just rolled in 2nd next to the truck and it died with the clutch pulled in. Wouldn't restart and was slower to turn over than normal. I checked battery voltage just in case it wasn't charging, had 12.81v. Voltage may have been a hair low but shouldn't be a big problem since it started with that and I had tried to start it for a minute draining it a bit. It started after driving about 5 minutes on the road in the truck back to my house. I'm really thinking something isn't liking heat and is failing when hot. Slow to turn likely isn't the coil. Still going to check fuel pressure if my fittings come in tomorrow. Should have already been here.
 

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Discussion Starter · #11 ·
Got the fuel pressure checked. Doesn't hit the mark until it is actually running. But when it does it stays steady at 39 psi. I can crack the throttle and only see movement of maybe .5 psi. I ran it for 5 minutes with no issues and gave it throttle randomly and tried to simulate actual riding. Just doesn't vary. Didn't want to run it too long. So I am doubting that is the issue. Any other thoughts?
 

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Only way to completely eliminate the fuel pressure is to check it wile it is acting up. You also should be able to cycle the key a couple times to prime the fuel system with out starting it and have the fuel pressure hold pressure for at least 5 seconds.

There use to be a problem with the connector that connects to the key switch, it would pull one of the wires out just far enough to make it randomly die.

you could install a small LED in to the injector plug to monitor the injector pulse, should be able to slide the wires in the connector beside the wires. this will tell you if your getting an injector pulse when it won't start.

Only other thing to check to help you start in the right path is spark when it will not start.

J M .02
 

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Discussion Starter · #13 ·
Not positive how I will check it when that happens but perhaps I can figure something out. Ride it with no plastics or something next week.

I actually replaced the key switch. But the issue isn't that it just dies, it won't start back up after it dies. So key switch shouldn't be the problem since it does crank, just cranks slow. Going to go through and check everything off of the list electrically. Probably will buy an AMR monster coil, no not for the "performance". Mostly so that I can get a cheaper new coil. New coil is 70 without the plug cap. So it is cheaper, hate buy used stuff like coils.
 

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I know what your saying with the Key switch and I am not saying it is it but there is a circuit in it to shut it off, not connected with the cranking circuit. if you checked it I'm sure it is not the problem.

still the best approach is to find out when it will not restart if it is the lack of spark and or injector pulse. crank trigger may be the problem if both are absent.
 

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Discussion Starter · #15 ·
Rough one to diagnosis. Appreciate the help man.

I set the TPS properly today. It was off a little but not a whole lot. Now centered at .594 v. I also found that the fuel pump plug wasn't seating fully. That wasn't it though, I could hear the pump cycle when I would turn the key on and off when it wouldn't start. Soldered a new plug in and it's good to go now. Also checked the coil. 11 kilo ohm and .6 ohm resistance so it looks good. But I have seen it fail warm on an XR250 if I remember correct. So may still replace.

This thing will be sick when I'm done with it.
 

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Are you having the same problems still. Im having somewhat the same problems, i haven't got around to fixing or to start troubleshooting it either.
 
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