A Cry for Help

[Ducati999]

I know this is a Ninja 250 site but I know some members have SV 650's and I am out of ideas.

(Alex, please move this if it should be elsewhere)

I don't usually need help fixing bikes but this has me stumped! The bike is a 2000 Suzuki SV 650N Gen1. Bike was crashed and last owner swapped in another 650 motor. Unknown year/mileage. The problem we are having is no spark. We have a second running gen 1 to swap parts from and have tried the ECU, Crank position sensor, coils, wires and plugs. We have tested all the wires from the CPS to the ECU, ECU to the Ignition switch, and just about everything else. Still no spark. We used the Crank Position Sensor (CPS) from the running bike and the one on the bike and we have tried the ECU/Ignitor box from the bike and the running bike in every combination but still no spark. We tested the wires between the CPS and the ECU and there is no break and from the ECU to the Coil there is no break. The ECU does not seem to be getting the signal to fire the coils but all the parts work on the running bike. This looks like the wires would have to be bad but they check out with a meter. Any ideas would be great as we have to get this bike done so I can get back to work on my bikes.

Thanks
Ant

[csmith12]

Tip over, and safety switches all check out fine?

[csmith12]

Also, try testing the start switch itself

[DannoXYZ]

Originally Posted by Ducati999

The ECU does not seem to be getting the signal to fire the coils but all the parts work on the running bike. This looks like the wires would have to be bad but they check out with a meter. Any ideas would be great as we have to get this bike done so I can get back to work on my bikes.

Thanks
Ant

Are you SURE that crank-sensor signal is generated at sensor but doesn't arrive at ECM? My most useful tool is oscilloscope. Since you have working bike, it's very easy to compare signal.

1. Start at crank-sensor pickup and capture waveform at plug.
2. Work upstream and verify signal at next connector on harness
3. Check that waveform makes it all the way to ECM
4. Verify polarity of signal, most systems are configured to use upward slope as start of trigger signal

Do you have CHEC showing on dash? Do you know how to make dash display Cxx error codes?

Make sure you have valid signal from TPS, MAP, ECT, IAT sensors and PAIR solenoid. ECM will not fire if any of these are incorrect.

The suggestion on safety-interloc points to very common issues. Check status of clutch, neutral and tipover switches. Verify that side-stand switch AND side-stand relay are working properly.

As with anything else, troubkeshoot one component at a time

[Ducati999]

The 2000 MY does not have any TIP OVER or other safety device. The Clutch and kick stand switches are both working correctly as the bike will not crank if the stand is down and the clutch not pulled in and we have no issue with cranking just no spark. The Gen2 SV 2003-2009 have both tip over and anti theft but this Gen1 does not. We have exchanged the CPS with a known working unit but have not checked it with a signal generator (on order). Everything seems to be right and we can manually trigger the coils by grounding but the Ignightor/ECU will not trigger them.

Thanks for the replies

[DannoXYZ]

Yes but is the side-stand relay working? Because that's what provides power to the fuel-pump and ECM. Not talking about cranking, but actual power supplied to the ECM. Ground the diagnostic terminal on ECM and have it display error-codes on dash:

C12 = crank position sensor
C13 = MAP sensor
C14 = TPS sensor
C15 = ECT sensor
C21 = IAT sensor

Since the engine was swapped, it can very well be possible that one of these sensors were damaged, or not hooked up properly. They ALL have equal-weighting on ECM's operation. That is, if any one of them was out-of-spec, the ECM will not function.

You need to gather correct data:

1. what is TPS output-voltage with key ON before cranking?
2. what is MAP output-voltage?
3. what is ECT output?
4. what is IAT output?
5. the crank-sensor also has some adjust-ability and ECM needs to see a minimum peak-to-peak voltage height in order to see a valid waveform.

VR signals are very weak and wiring that passes a continuity test may still attenuate a VR signal. This can of course, be confirmed in differences in waveforms at the sensor itself, vs. what's going into ECU. Not sure of this particular model, but many harnesses uses coaxially-shielded cables for the VR sensor signals and sometimes, the outer shielding-braid may fray and short out the inner-conductor.

I suspect your crank-sensor is fine. It may very well be one of the other sensors. Definitive testing yields numbers in concrete black & white, all-or-nothing terms. Without numbers, you're guessing.

[DannoXYZ]

Here's what the crank-sensor signal should look like going into ECM. Needs a ~10v peak-to-peak difference, or +/- 5v, in order for ECM to distinguish a tooth. The missing tooth indicates TDC.



It actually uses a nifty trick with comparing with IAP/MAP sensor to determine TDC of each cylinder rather than needing a cam-sensor.

Speaking of the IAP/MAP sensor, make sure the hoses going to each cylinder is not out-of-phase, the positions are not interchangeable.

[Ducati999]

Originally Posted by JacRyann

Yes but is the side-stand relay working? Because that's what provides power to the fuel-pump and ECM. Not talking about cranking, but actual power supplied to the ECM. Ground the diagnostic terminal on ECM and have it display error-codes on dash:

C12 = crank position sensor
C13 = MAP sensor
C14 = TPS sensor
C15 = ECT sensor
C21 = IAT sensor

Since the engine was swapped, it can very well be possible that one of these sensors were damaged, or not hooked up properly. They ALL have equal-weighting on ECM's operation. That is, if any one of them was out-of-spec, the ECM will not function.

You need to gather correct data:

1. what is TPS output-voltage with key ON before cranking?
2. what is MAP output-voltage?
3. what is ECT output?
4. what is IAT output?
5. the crank-sensor also has some adjust-ability and ECM needs to see a minimum peak-to-peak voltage height in order to see a valid waveform.

VR signals are very weak and wiring that passes a continuity test may still attenuate a VR signal. This can of course, be confirmed in differences in waveforms at the sensor itself, vs. what's going into ECU. Not sure of this particular model, but many harnesses uses coaxially-shielded cables for the VR sensor signals and sometimes, the outer shielding-braid may fray and short out the inner-conductor.

I suspect your crank-sensor is fine. It may very well be one of the other sensors. Definitive testing yields numbers in concrete black & white, all-or-nothing terms. Without numbers, you're guessing.

Mr. Ryann,
Thank you for the response again. This is a 1st Gen SV with Carbs and no MAP, ECT nor IAT. The gen 1 also has no "computer" to give codes. The Gen 2 does have the plug you can jumper and get the codes (I had a 2003) but the earlier versions do not. We do not have access to an Oscillascope but as I indicated above, we have ordered a Peak voltage sensor to check the signal from the CPS. The TPS is fine but would not prevent spark should it even be unplugged that just adjusts the timing/ignition map but the motor will run without it and lots of people unplug them for the track.

I really do appreciate your input I just want to get all the info out there so someone might give me the right direction to continue. I have rebuilt and repaired hundreds of bikes in my time and I have never had an issue like this.

Ant

[DannoXYZ]

Sorry, got generations mixed up. Let me check with SV650 rider down road from here. She had this exact problem couple weeks ago. Tried her CDI box in other bike and it worked. Measured her crank-sensor at correct ohms, so that was good too. They were looking at borrowing scope next and tracing signal upstream on harness.

Couple things to check:

1. Power to CDI box?

2. Model-year of swapped-in engine? It has flywheel/crank-trigger teeth pattern for carbed engine and not EFI? How many teeth on outside of flywheel?

[jkv45]

Originally Posted by Ducati999

I know this is a Ninja 250 site but I know some members have SV 650's and I am out of ideas.

(Alex, please move this if it should be elsewhere)

I don't usually need help fixing bikes but this has me stumped! The bike is a 2000 Suzuki SV 650N Gen1. Bike was crashed and last owner swapped in another 650 motor. Unknown year/mileage. The problem we are having is no spark. We have a second running gen 1 to swap parts from and have tried the ECU, Crank position sensor, coils, wires and plugs. We have tested all the wires from the CPS to the ECU, ECU to the Ignition switch, and just about everything else. Still no spark. We used the Crank Position Sensor (CPS) from the running bike and the one on the bike and we have tried the ECU/Ignitor box from the bike and the running bike in every combination but still no spark. We tested the wires between the CPS and the ECU and there is no break and from the ECU to the Coil there is no break. The ECU does not seem to be getting the signal to fire the coils but all the parts work on the running bike. This looks like the wires would have to be bad but they check out with a meter. Any ideas would be great as we have to get this bike done so I can get back to work on my bikes.

Thanks
Ant

Are you on SVRider.com? This is the 1st Gen Tech the section - http://www.svrider.com/forum/forumdisplay.php?f=13

There are some really good troubleshooter there - "Tovar", "TeeRiver", and "RecoilRob" come to mind.

Those guys are amazing.

[Ducati999]

Originally Posted by jkv45

Are you on SVRider.com? This is the 1st Gen Tech the section - http://www.svrider.com/forum/forumdisplay.php?f=13

There are some really good troubleshooter there - "Tovar", "TeeRiver", and "RecoilRob" come to mind.

Those guys are amazing.

Been on the SV sites (I am a member) for years. I have read all the related threads and tried just about everything. I am starting to think the flywheel might have taken a hit and be just enough out of round to not signal the entire way around. Just a theory at this point and I have another one. I will wait till the Peak Voltage meter comes in to confirm that the Crank sensor is sending the proper signal. I have not yet started a thread to get the "guru's" opinion on this issue.

Thank you all again for your thoughts they have given us a few new ideas on where to focus.

Ant

[Ducati999]

Hey everyone,
Been a while since I have had any time to get on the net. I really appreciate all the input on this issue and I have some good news. The problem I needed help with was the lack of spark on both cylinders for a 2000 SV650. We have a second running bike to swap parts from and make comparison tests yet weeks went by and still no spark (bike is names Sparky). We swapped, tested, cleaned and set tolerances and any and everything that even remotely could prevent the coils from making spark yet still nothing!

I am happy to tell everyone today that "Sparky lives". After approx. 40 hours of troubleshooting, we found a broken wire on the steering head right where a steel wire holds the wiring harness to the frame! The last owner had claimed he replaced the harness due to the "lack of spark issue". There is even an extra harness in the boxes (yes boxes) of parts. He told us he had swapped the harness yet still had the same issue. I am calling him a liar! We found a +5V DC current on the negative side of the rear coil. Initial tracing pointed towards the tach but after disassembly and testing, the tach was fine. When I removed the tach, I pulled the entire front of the bike apart and when replacing the tach I saw a break in the loom over the harness under the retaining wire. After repairing the wire we have bright blue spark and a happy owner!!!!! Thank you all for your help and suggestions. Now you can see why it was so hard to find the cause of this issue.