Closed Ignition: Primarily Pre-1998
A "Closed" ignition means the wiring needs to have a closed circuit in order to run. If the connection to any switch; key, kill, tether, throttle safety switch, etc.. is interrupted, you 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 an open ignition.
Diagnosing no spark, weak spark or intermittent spark issues
First you want to see if it an issue in the switches/handlebars or if it is in the primary ignition components: stator, cdi, coils, trigger coil or possibly plugs, plug wires or plug caps.
AC regulator was unplugged: It still sparked when pulled over
DC regulator was unplugged: It still sparked when pulled over
With the Blue relay unplugged on the back of the EFI box: It clicked, no fuel priming but it still sparked
With the Brown relay unplugged on the back of the EFI box: No click, no fuel priming but it still sparked
With the kill switch pressed down: it would not prime the fuel pump and no spark
With the tether pulled: it would not prime the fuel pump and no spark
With the 4 prong plug from the stator to the wiring harness unplugged: It still sparked
With the air temp sensor unplugged: It still sparked
1996 and earlier
1 long & 1 short = Open or short in Throttle Position Sensor
1 long & 3 short = Open or short in intake Air Temp Sensor
1 long & 4 short = Open or short in Engine Coolant Temp Sensor
2 long & 1 short = Faulty #1 mag injector control circuit in ECU or open or short in circuit to the #1 injector
2 long & 2 short = Faulty #2 pto injector control circuit in ECU or open or short in circuit to the #2 injector
4 long & 1 short = open or short in the injector timing sensor
4 long & 2 short = open or short in the ignition timing sensor
1997-On Models
1 flash = Open or shortin Throttle Position Sensor
2 flash = Open or short in Engine Coolant Temp Sensor
3 flash = Open or short in Intake Air Temp Sensor
4 flash = Open or short in the barometric Pressure Sensor
5 flash = Faulty Fuel Injectors
6 flash = Servo failure
19. Other issues that I have seen/read that have caused a no spark/bad running issue:
A. Wrong flywheel on it.
B. Frayed wires in the wiring harness or under the seat caused a short
C. It kept fouling plugs left and right. The guy before me ran ethanol, and never told me. This was on an EFI sled.
D. Hood harness was routed between rewind/stator housing and frame and had 4 wires smashed. Repaired wires and ran good.
E. Got it running again tapped the ECU and died. Pulled the ECU cover off and found some corrosion
F. Wires running to the carbs were rubbing against the jack shaft (Shaft going from secondary clutch to the top sprocket in the chain case). After rewrapping/rerouting the wires it ran great
G. Bolt for the recoil cup broke off and hit the trigger coil, bent the bracket slightly and gave it too much air gap. Air gap between the trigger coil and flywheel should be around .010-.020. I know it will not fire if the gap is .040.
H. Oil Injection turned up too high
I. Fuel Lines hooked up backwards
J. Lean jetting will cause a bog. The sled would start and idle but if you pinned the throttle the sled would bog and quit running. We were able to determine that it ran better when you choked it a little. We jetted up and it ran good.
K. Sheared Timing key
L. Crank out of Phase will cause it to run very poorly.
M. Too much dielectric grease in the trigger connector caused sled to bog.
N. The wire on the carburetor was put on backwards
O. Loose key switch wire
P. a loose terminal on the key switch
Q. Harness got to close to the pipe and fused wires together causing no spark issue
R. I have seen the wire from the CDI to the coils break right up close to the CDI box
S. When using a battery and VDO gauge: Turned out to be an $8.00 dollar relay. It was energizing the VDO rev limiter. That's why I had spark when the battery was disconnected.
T. The original issue was that the 1993 ZR700EFI would spark the spark plugs 1 time ...and here is the strange part…you pulled it over with the key in the “on position” first without the plugs sparking and only when you turned the key to the off position the spark plugs would spark 1 time. There was never any spark when the key was in the on position. Here is the root cause of the failure according to the owner of the sled: What I thought was the ignition trigger coil was the EFI sensor on the outside of the flywheel housing. The trigger is behind the flywheel and is dead as a doornail. I disconnected the trigger on my 580 EFI (Which mimics having a dead trigger and no pulse to the CDI) and checked for spark. There wasn't any spark when pulling it over with the key in the on position but when I turned the key off both plugs fired one time, just like my 1993 ZR700Wildcat EFI.
U. the coil was good but it had a bad plug wire
V. Open the gas cap and see if it will start. I have seen cases where a plugged vent in the tank will cause the tank to develop a vacuum that the fuel pump cannot overcome
W. On an F-1000 sled; it was a chaffed wire in the harness. it was the harness right above the stator that passed through the right bulk head
A "Closed" ignition means the wiring needs to have a closed circuit in order to run. If the connection to any switch; key, kill, tether, throttle safety switch, etc.. is interrupted, you 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 an open ignition.
Diagnosing no spark, weak spark or intermittent spark issues
First you want to see if it an issue in the switches/handlebars or if it is in the primary ignition components: stator, cdi, coils, trigger coil or possibly plugs, plug wires or plug caps.
- There is both an EFI fuel management system box on it and a CDI box on it. The type of fuel injection system, magneto powered or battery powered, can be identified by the color/location of the ECU box. on battery powered systems, the ECU is located next to the chaincase and the box is shiny (aluminum). on batteryless systems the ECU is mounted on the airbox and is black.
- First 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.
- Pull the recoil rope checking the spark at the plug. Is there spark at each spark plug? Is the spark blue (indicating a strong spark) or is it yellow/orange (indicating a “weak” spark). If you have nice blue spark on one plug (if it is a twin) or two plugs (if it is a triple) and not the others, it may be as simple as having a bad/fouled out plug. Try replacing the non-sparking or weak sparking plug/plugs with new a new plug.
- On the Battery EFI sleds the battery voltage is very important. If you have a weak, dead or corroded battery, you will not have spark. As mentioned in step 6, there is an in line 15 amp fuse that is located close the battery coming off of the + or positive side of the battery cable. If that is blown, you will not have spark.
- The stator has 2 plugs and at least one ground wire coming from it (some models have 2 ground wires). The 4 prong plug only goes to the DC and AC regulators and the 3 prong plug goes to the CDI box. The 3 prong plug is only wired to the ignition coils on the stator. Depending on the wiring diagram you look at the DC regulator goes to several places including charging the battery. The AC regulator powers the traditional things like gauges, hand warmers and lights. Only on the CARB sleds you can unplug the 4 prong connector from the stator containing the 2 yellow wires and 2 non-yellow wires and use a jumper wire on the 2 non-yellow wires to bypass all switches, the wiring harness ect... You CANNOT do this on the battery EFI models. As previously mentioned the 4 prong plug from the stator on the battery EFI models only goes to both the AC and DC regulators and is not part of the ignition like it is on the carb sleds.
- If the battery is charged and there is no spark: the likely culprit is probably one of the ignition components like the stator, TSS, tether, trigger, kill switch, in line 15 amp fuse is blown (in line close to the battery positive terminal) or ground wire broken/not making good contact. Of course you could end up having a bad CDI box or coils, but that likelyhood is low…not impossible but low.
- There is a 3 prong connector in your handlebars that if you unplug and jump the male and center female connectors it will bypass your kill switch and your TSS switch. It does not bypass your key switch or your tether. After bypassing these switches you will only be able to start and turn off your sled with the key or tether. The 3 prong connector is usually not by the thumb throttle but rather just a little bit down the steering column 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 from right handlebar area down to where the plug is located. I have a video on youtube showing how to bypass your tss/kill switch for testing purposes. If you bypass the TSS/kill switchs and you have spark, then you know that one or both possibly even both of them are bad.
- If you bypass the tss/kill switch and do not have any spark then you also need to test the tether connection by bypassing the tether. You can just cut the wires in the back of the tether and splice the wires together which "completes" the circuit, you can use a jumper wire on the back of the tether so it “completes” the connection or you can even install a new or used tether to check it. Remember if you replace it with a used tether, the used tether could be bad or it could be an “open loop ignition” tether and will not work correctly on your model. The tethers are known for going bad sometimes and causing intermitten spark issues.
- If you’ve checked everything and still don’t have any spark you could have a short somewhere in the wiring harness. There is no easy way to find these. Sometimes you can just wiggle the harness at different points and see if you get spark when you pull it over. If you all of a sudden do get spark, you should be able to narrow down an approximate location of the short and fix it.
- Also be sure to check the connection from the stator to the cdi. Make sure all connections are free of moisture, are tight and use a little bit of dielectric grease on it. This also goes for the trigger/pulser coil 2 wire connection going from the trigger to the CDI. 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.
- If all connections are solid and the ground checks good then you start electrically checking components. Cat pretty much just uses 2 triggers: One trigger ohm specs are 90-100 or so with new ones up to 115ohms. The other trigger used is 170-190 ohms. If your trigger measures in one of these 2 ranges then it is probably ok. Many of the manuals give the wrong trigger spec for the wrong models. If your manual calls out a 90 ohm trigger and yours measures 178, then yours falls into the other category and is actually ok. If you have a trigger that ohms out at 260ohms, 0 ohms or 40 ohms when cold..then more than likely your trigger is bad especially if it measures 0. I have a video on youtube showing how to check 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.
- Next you want to test the stator itself. I have several videos for different models on youtube. I show how to test a couple of different kinds of EFI stators. Most Battery EFI Stators have ohm specs of 450ohms and 45ohms.
- If you continue to have no spark/weak spark and both your trigger and stator test ok then we may be looking at a secondary coil issue. First you want to make sure the spark plug caps are on tight. They just screw on and off the spark plug wire. If your wires are long enough 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, some spark plug wires unscrew from the coil itself. I had 2 sets of coils go “bad” on my sled. My triple coils showed 1 spark plug with extraordinary blue spark and the other 2 plugs were weak/yellow-ish in color. After I trimmed them and screwed them back together they ran perfect. Warn spark plug ends usually cause a miss or acts like a rev limiter. Be warned though that I did have one wire that would not unscrew from a coil and I ended up tearing the spark plug wire. Also, always check the spark plug gap and set it to the correct specifications.
- If you have no spark and your trigger tests ok, your stator tests ok and you have trimmed the plug wires, grounds are good ect… then we’re looking at the possibility of a 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. There are specialty testers that can check the DC voltage coming out of the CDI box, but they are expensive.
- There is always the chance you have a bad key switch.
- 13. Lastly, if everything ohms out ok, tests ok, but you still don’t have spark or have a weak spark condition ect….you may want to take the stator out of the sled or put the snowmobile in a warm room if your stator ohms are a little on the low side. I have seen stators that ohms out at 430 and 44 in the cold, but when you bring them up to room temp (50-70 degrees F), one of the ignition coils will measure higher than it is supposed to. On a 450 & 45 ohm stator for instance; if the low speed coil measures 455 when it is at 50-70 degrees F, then it is bad. If the 45ohm high speed coil is at 48 ohms when tested at 50-70 degrees F, then it is bad. If an OEM stator ever measures higher than the specs given, it is bad. I have seen several measure anywhere from 420-440 when cold but only after they were warmed up to 50-70 degrees F did their stator ohms actually measure higher and reveal that the stator was actually bad.
- Here are a few things I tested/checked to see if they had any bearing on the ignition spark:
AC regulator was unplugged: It still sparked when pulled over
DC regulator was unplugged: It still sparked when pulled over
With the Blue relay unplugged on the back of the EFI box: It clicked, no fuel priming but it still sparked
With the Brown relay unplugged on the back of the EFI box: No click, no fuel priming but it still sparked
With the kill switch pressed down: it would not prime the fuel pump and no spark
With the tether pulled: it would not prime the fuel pump and no spark
With the 4 prong plug from the stator to the wiring harness unplugged: It still sparked
With the air temp sensor unplugged: It still sparked
- Also, bad reeds on a sled will cause it to back fire and run poorly acting like it is an electrical issue.
- Codes the ECU will flash:
1996 and earlier
1 long & 1 short = Open or short in Throttle Position Sensor
1 long & 3 short = Open or short in intake Air Temp Sensor
1 long & 4 short = Open or short in Engine Coolant Temp Sensor
2 long & 1 short = Faulty #1 mag injector control circuit in ECU or open or short in circuit to the #1 injector
2 long & 2 short = Faulty #2 pto injector control circuit in ECU or open or short in circuit to the #2 injector
4 long & 1 short = open or short in the injector timing sensor
4 long & 2 short = open or short in the ignition timing sensor
1997-On Models
1 flash = Open or shortin Throttle Position Sensor
2 flash = Open or short in Engine Coolant Temp Sensor
3 flash = Open or short in Intake Air Temp Sensor
4 flash = Open or short in the barometric Pressure Sensor
5 flash = Faulty Fuel Injectors
6 flash = Servo failure
19. Other issues that I have seen/read that have caused a no spark/bad running issue:
A. Wrong flywheel on it.
B. Frayed wires in the wiring harness or under the seat caused a short
C. It kept fouling plugs left and right. The guy before me ran ethanol, and never told me. This was on an EFI sled.
D. Hood harness was routed between rewind/stator housing and frame and had 4 wires smashed. Repaired wires and ran good.
E. Got it running again tapped the ECU and died. Pulled the ECU cover off and found some corrosion
F. Wires running to the carbs were rubbing against the jack shaft (Shaft going from secondary clutch to the top sprocket in the chain case). After rewrapping/rerouting the wires it ran great
G. Bolt for the recoil cup broke off and hit the trigger coil, bent the bracket slightly and gave it too much air gap. Air gap between the trigger coil and flywheel should be around .010-.020. I know it will not fire if the gap is .040.
H. Oil Injection turned up too high
I. Fuel Lines hooked up backwards
J. Lean jetting will cause a bog. The sled would start and idle but if you pinned the throttle the sled would bog and quit running. We were able to determine that it ran better when you choked it a little. We jetted up and it ran good.
K. Sheared Timing key
L. Crank out of Phase will cause it to run very poorly.
M. Too much dielectric grease in the trigger connector caused sled to bog.
N. The wire on the carburetor was put on backwards
O. Loose key switch wire
P. a loose terminal on the key switch
Q. Harness got to close to the pipe and fused wires together causing no spark issue
R. I have seen the wire from the CDI to the coils break right up close to the CDI box
S. When using a battery and VDO gauge: Turned out to be an $8.00 dollar relay. It was energizing the VDO rev limiter. That's why I had spark when the battery was disconnected.
T. The original issue was that the 1993 ZR700EFI would spark the spark plugs 1 time ...and here is the strange part…you pulled it over with the key in the “on position” first without the plugs sparking and only when you turned the key to the off position the spark plugs would spark 1 time. There was never any spark when the key was in the on position. Here is the root cause of the failure according to the owner of the sled: What I thought was the ignition trigger coil was the EFI sensor on the outside of the flywheel housing. The trigger is behind the flywheel and is dead as a doornail. I disconnected the trigger on my 580 EFI (Which mimics having a dead trigger and no pulse to the CDI) and checked for spark. There wasn't any spark when pulling it over with the key in the on position but when I turned the key off both plugs fired one time, just like my 1993 ZR700Wildcat EFI.
U. the coil was good but it had a bad plug wire
V. Open the gas cap and see if it will start. I have seen cases where a plugged vent in the tank will cause the tank to develop a vacuum that the fuel pump cannot overcome
W. On an F-1000 sled; it was a chaffed wire in the harness. it was the harness right above the stator that passed through the right bulk head