Join Date: Jul 2004
Location: Flushing, Michigan
Thanked 193 Times in 178 Posts
Sled: 2000 ZRT 1107 Ron Hunyady Motor
09-10 Mileage: 1000
08-09 Mileage: 1000
07-08 Mileage: 1000
06-07 Mileage: 1000
COuld be a dying stator or your coil wires aren't making good connection. Here is my procedure:
Closed Ignition: old style ignition. Primarily Pre-1998
A "Closed" ignition means that the wiring needs to have a closed circuit in order to run. If the connection to the switches; key, kill, tether, throttle safety switch, etc.. is interrupted there will no longer be power to the ignition system and spark will cease. All Cats 1997 and earlier run a closed ignition, with the exception of the 1997 ZR 580 that is open ignition.
Diagnosing no spark, weak spark or intermittent spark issues
The first thing you want to do is see if it an issue in the switches/handlebars or if the issue is in the primary ignition components like the stator, cdi, coils, trigger coil or possibly plugs, plug wires or plug caps.
1. The first thing you want to do is take the spark plugs out of the cylinder heads, put the spark plugs in the spark plug boots and lay them on a cylinder head bolt so they are grounded. Make sure the plugs are not near the spark plug holes when you pull it over.
2. Pull the recoil rope and check the spark at the plug. Is there spark at each spark plug? Is the spark blue (indicating a strong spark) or is it yellow (indicating a “weak” spark).
3. The next step is pretty much the same if you had no spark or a weak spark. On the “Closed” ignition you unplug the connector from the stator containing the yellow wires. This connector sends the power to the lights, hand warmers and tachometer. When you unplug this connector you need to put a wire connecting the 2 “non yellow” wires together in the connector. This completes the electrical circuit which is needed to check for spark. By putting this jumper wire between the 2 non yellow wires you are bypassing all of your switches (Throttle Safety Switch, Kill, tether ect..) all of your lights and hand warmers ect..in your handlebars. Pull the recoil over and see if you have spark or if the previous yellow weak spark is now blue. Carbureted models can be started and run with this 4-prong connector unplugged and the jumper wire in it but you won’t have lights ect..as mentioned before. If you have an EFI, you can only check for spark and it will not start or run with it unplugged. You need it plugged in to power your fuel pump.
4. If you had no spark and by unplugging the 4-prong connector and using the jumper wire you now have spark, that tells you that you have something shorted out in your switches like the tether, throttle safety switch or kill switch. If you had weak spark and now have blue spark it also tells you that you have a short with one of your switches. Again likely culprits are the TSS, tether or kill switch. There is a 3 prong connector in your handlebars that if you unplug and jump the 2 outside prongs it will bypass your kill and TSS switch and you will only be able to start and turn off your sled with the key. The 3 prong connector is usually not by the handlebars next to where you put your hands but rather just a little bit down the steering shaft about at the point where the console containing the key switch is located. If you’re not sure which connector it is, just follow the group of wires out of the right handlebar area where the TSS and Kill switch are located down to where the plug is located. There are a few other plugs by the handlebar on the right side by the thumb throttle, but they contain yellow wires and are for your hand warmers and thumb warmer. You also need to bypass the tether. You can just cut the wires in the back of the tether and splice the wires together which "completes" the circuit and bypasses the tether.
5. If after unplugging the 4-plug switch and using the jumper wire you still do not have spark or the spark continues to look weak this tells you that the problem is in the major ignition components like the stator, coils, cdi, spark plugs, spark plug wires or trigger coil.
6. The first thing to check are the connections from the stator to the cdi. Make sure all connections are free of moisture, are tight and use dielectric grease on it. Check the ground. You should have a ground wire coming from your stator and your CDI/ECU box. Make sure the grounds are clean, tight and that the ground wires are not broken. Sometimes the ground wire is pinched and broken inside the eyelet connection and is making only intermittent if any connection. Some older model Arctic Cats have the ground up closer to the handle bars on what some would consider the “firewall” of the sled and they are notorious for rusting/corroding out badly.
7. If all of the connections are solid and the ground looks good then you have to start electrically checking components. Check your manual to be sure what your specific specs are for testing the trigger. Most twins are 90 ohms and most triples are 175 ohms. View my “testing a pulser/trigger coil” video link in my signature to see how to test it. It is very easy and quick to test. The frustrating part about the trigger coil is that it can test good, but still be bad.
8. Next you want to test the stator itself. View my “How to test a stator” video link in my signature to see how to do it.
9. If you have no spark and your trigger tests ok and your stator tests ok then we’re looking at a possible bad CDI box There is no real good way to test the CDI other than swapping the box out with a known good CDI box.
10. If you have continue to have no spark/weak spark and your trigger tests ok and your stator tests ok then we may be looking at a secondary coil issue. The coils can have a couple of issues with them. The first thing you want to do is make sure the spark plug caps are on tight. They just screw on and off the spark plug wire. Many times the best thing to do as long as your wires are long enough is to unscrew the spark plug caps, trim a ½ inch off the end of the wire and then screw the spark plug cap back on. Also, you can unscrew the wire from the coil itself and do the same thing. Trim off about a ½ inch and screw it back on the coil. I had 2 sets of coils go “bad” on my sled and come to find out it was just the spark plug wires were a bit warn at their ends and after I trimmed them and screwed them back together they ran perfect. This condition usually causes a miss. My triple coils showed 1 spark plug with extraordinary blue spark and the other 2 plugs were weak and yellow-ish in color. Be warned though that I did have one wire that would not unscrew from a coil no matter how hard I tried to turn it and I ended up just tearing the spark plug wire. Also, always check the spark plug gap and set it to the correct specifications for that plug. As far as putting the coil wires back on here is a general rule of thumb for Cats:
Most sleds fire all the plugs at the same time, multiple times per revolution. A twin will fire both wires twice each revolution, a triple three times (once per 120 degrees because every 120 degrees one of the pistons is at TDC). One of the pulses fires the plug to ignite the fuel/air mix, the other times the pulses are "lost" as the plug fires with the piston not ready for the fuel to burn. That prevents having to have a complex distributor of some kind to route the electricity to the cylinder that needs it. On those types of ignitions, firing order (which spark plug wire goes on which spark plug) is not important.
11. Specificly on Battery EFI sleds here is another thing to check. This was found on a 1996 EXT EFI: There can be a bad relay on the back of the ecu. There are 2 of them back there 1 for the spark and 1 for the fuel pump.
12. Also, bad reeds on a sled will cause it to back fire and run poorly acting like it is an electrical issue.
13. Sled won’t shut off condition: I have seen a few things cause this. First off it is usually a bad ground/broken ground wire. Sometimes it is moisture in the connector from the stator to the CDI. I disconnected my TSS/Kill switch the day my kill switch got moisture in it and my sled wouldn’t shut off. You could have a cdi with an internal short. A bad stator has caused a machine to not shut off.
14.Other issues that I have seen/read that have caused a no spark/bad running issue:
A. Guy bought a used sled with the wrong flywheel on it.
B. Frayed wires somewhere in the wiring harness or under the seat were causing a short
C. Guy said sled was only running on one cylinder. He removed one spark plug wire and it didn’t effect the way the sled ran. His low side coil on his stator read 360 ohms and it should have measured 450 ohms. His low side coil was dying.
D. 96 ZRT would run like crap if the carbs weren't synced right
E. After I replaced the trigger coil last year, I did not route the red/white wire good (Wire coming from the stator to the CDI). It laid against the crankshaft, rubbed the insulation off and exposed 1 tiny strand of wire! I cleaned the wire and put 2 shrink tubes on it. Then RE-ROUTED the wire to fix it.
F. Hood harness was routed between rewind/stator housing and frame and had 4 wires smashed. Repaired wires and runs perfect.
G. Got it running again tapped the ECU and died. Pulled the ECU cover off and found some corrosion
H. I had a 580 that did not spark all the time and it was a bad ground wire from the ECU/CDI box. The factory has them grounded through the steering column support which is bolted to the chassis and over time the bolts get rusted and it loses its ground.
I. Bolt for the recoil cup broke off and hit the trigger coil, bent the bracket slightly and gave it too much airgap
J. Oil injection turned up too high
K. Fuel Lines hooked up backwards
L. I once saw a guy who had just swapped out motors and the jetting was way too lean. The sled would start and idle but if you pinned the throttle the sled would bog and quit running. By using the choke we were able to determine that it ran better when you hit the throttle and after jetting up it ran good.
M. Sheared Timing key
N. Crank out of Phase will cause it to run very poorly.