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Discussion Starter · #1 ·
I just can't get my 1992 RXL to run, the sled just suddenly died last winter when riding up a glacier, it had only been going a few minutes when that happened.
If I clear the cylinders and put in fresh plugs it will maybe fire for 2 seconds before it dies, otherwise, it never really catches, just the occasional bang. I've tried starting fluid, I've tried disconnecting the fuel injection and running it on starting fluid also, nothing really works.
Ignition coil resistance is right, all the coils in the magneto measure right too within 1% of what the manual says. Select monitor displays all sensor values normal, no fault codes, also reads RPM when I pull the cord and the fuel pump runs during cranking and priming.
I get spark, visible when I pull a plug out and hold it against the head while pulling the cord, but of course, that's with no fuel and no compression impeding the spark.
I'm starting to suspect the spark just isn't strong enough to maintain it. I have never had a CDI box fail on me before, but is that a failure mode that is not unheard of, weak spark?
I have another CDI box, but I have no idea if that one is good or just has the same failure mode, connecting that one makes no difference at all.
My right hand is sore from pulling the cord a 100 times today, so I decided to go brainstorm a bit. Please comment if you have any suggstions.
 

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CDI box, spark plug wires, fuel issue like plugged lines or filter or pump
My thoughts.
 

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baldur said:
I just can't get my 1992 RXL to run, the sled just suddenly died last winter when riding up a glacier, it had only been going a few minutes when that happened.
If I clear the cylinders and put in fresh plugs it will maybe fire for 2 seconds before it dies, otherwise, it never really catches, just the occasional bang. I've tried starting fluid, I've tried disconnecting the fuel injection and running it on starting fluid also, nothing really works.
Ignition coil resistance is right, all the coils in the magneto measure right too within 1% of what the manual says. Select monitor displays all sensor values normal, no fault codes, also reads RPM when I pull the cord and the fuel pump runs during cranking and priming.
I get spark, visible when I pull a plug out and hold it against the head while pulling the cord, but of course, that's with no fuel and no compression impeding the spark.
I'm starting to suspect the spark just isn't strong enough to maintain it. I have never had a CDI box fail on me before, but is that a failure mode that is not unheard of, weak spark?
I have another CDI box, but I have no idea if that one is good or just has the same failure mode, connecting that one makes no difference at all.
My right hand is sore from pulling the cord a 100 times today, so I decided to go brainstorm a bit. Please comment if you have any suggstions.
Try checking for fuel flow. On my 91 RXL I removed the return line to the tank. It turned out my pick up line in the tank had rotted off and I had no fuel. If you can get a pressure gauge on it, the pressure should be between 36-40 PSI I believe.
Any codes flashing on the ECU?
 

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Have you tried replacing the battery?
 

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Compression good?

Something build a nest in the can?

Check and clean the grounds?
 

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Discussion Starter · #6 ·
I'm going to measure fuel pressure and flow tonight, what confused me was that it didn't really run on starting fluid either and it looked like it was getting the plugs wet.
I should measure compression too, it feels like it has compression when I turn it over, and it did run for a couple seconds.
These motors are piston ported, no reed valves, right?
The exhaust flows free, I have no airbox and no can on it for testing.
 

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Discussion Starter · #7 ·
Ok, it runs now. Turned out to be a faulty ECU.
Luckily, I bought a spare ECU last year to tinker with, plugged that in and the sled fired right up.
Looks like the old ECU had a problem in the injector outputs because all of the sensor values were reading correct in the select monitor, and it was running the fuel pump reading RPM.
 

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baldur said:
Ok, it runs now. Turned out to be a faulty ECU.
Luckily, I bought a spare ECU last year to tinker with, plugged that in and the sled fired right up.
Looks like the old ECU had a problem in the injector outputs because all of the sensor values were reading correct in the select monitor, and it was running the fuel pump reading RPM.
Glad to hear you found and fixed the problem.[thumb]
The select monitor and mrholmquest help were a godsend for me. Good luck with the RXL, I loved mine even though it had it's issues...[confused]
 

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I have an ECU just like that...

Everything works perfect, except that it stopped firing the injectors. It's now my test-bed ECU.
 
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