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ST4 Buggy Rail 05 GSXR 1000
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Discussion Starter · #1 ·
I have a built Sand Rail with GSXR K5 Engine in it. It has been running great and pulled it into the garage as I noticed it had slow start after riding it around. I checked the battery current with engine off 11.3V and then I started it and noticed no change in voltage stayed at 11.3V. So I put the battery charger on ( Battery still connected) like I do to my other UTV and when the battery after hour charging disconnected to run test to Stator wires. I pulled on the harness to find Stator wires to check if connected I manually disconnected stator wires to look at prongs all looked good. I do not know if pulling on harness or placing battery charger did something because I connected the stator back to test fire and on the LCD I noticed F1 on and oil light flickering - I opened the key switch and cranked and it cranked for 5 seconds and nothing. I noticed the pump would not prime when I would open key switch. I also checked fuses and checked Fuel Pump relay- the relay will not actuate when key is on. I swapped it for fan relay and still nothing. I unplugged relay and ran 12v and ground heard it click-- I ran 12v directly to inline pump and primes- I do not have any power going from yellow and red wires to pump- seems my ECM yellow and black wire Going to ECM is not being grounded internally---When I open the key switch I do here something in the engine but its not the full pump-----I am wondering if battery charger or pulling on harness fried my ECM ?
Any help will be greatly appreciated I have downloaded manual and thinking of ordering an ECM-- I will call dealer to have it tested--
I also did the Dealer Mode and got C041
 

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That is code for immobilizer
Check it's connected right and that you are using the original key, some copy have the shape but not the chip

Sent from my Redmi Note 9 Pro using Tapatalk
 

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ST4 Buggy Rail 05 GSXR 1000
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Discussion Starter · #3 ·
That is code for immobilizer
Check it's connected right and that you are using the original key, some copy have the shape but not the chip

Sent from my Redmi Note 9 Pro using Tapatalk
The unit was running fine with key - I placed battery charger and the issue started
 

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You should listen to me. No, seriously, listen to
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C41 is an issue with the fuel pump relay. Per the service manual:
No voltage is applied to fuel pump although fuel pump relay is turned ON, or voltage is applied to fuel pump although fuel pump relay is turned OFF.

That reeks of a faulty relay or, more likely, a wiring issue. Assuming that you have the cooling fan, try swapping its relay for the fuel pump (they're the same part). If that doesn't do anything, start measuring voltages. R/Bl should always be 12 V. There's a fuse or wiring problem if not. O/W should be 12 V when the ignition and RUN switches are on. There's a problem with the switches, ignition interlock relay, or wiring if not. Y/B is the relay control line to the ECM. It should go high (12 V) at first, then go low while the fuel pump primes, then go high until the engine starts, then go low again while running. The ECM controls that so there's a wiring problem (or the ECM isn't functioning) if it doesn't. The Y/R is the line to the fuel pump. It is monitored by the ECM and the service manual statement refers to what's happening on it. Note that the Y/R lead should behave the same at the fuel pump. O/W also provides power to the ECM and can be checked at the dealer mode connector, ignition coils, and fan relay.

Also see 4-79 & 4-80 in the service manual.
 

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ST4 Buggy Rail 05 GSXR 1000
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Discussion Starter · #11 ·
C41 is an issue with the fuel pump relay. Per the service manual:
No voltage is applied to fuel pump although fuel pump relay is turned ON, or voltage is applied to fuel pump although fuel pump relay is turned OFF.

That reeks of a faulty relay or, more likely, a wiring issue. Assuming that you have the cooling fan, try swapping its relay for the fuel pump (they're the same part). If that doesn't do anything, start measuring voltages. R/Bl should always be 12 V. There's a fuse or wiring problem if not. O/W should be 12 V when the ignition and RUN switches are on. There's a problem with the switches, ignition interlock relay, or wiring if not. Y/B is the relay control line to the ECM. It should go high (12 V) at first, then go low while the fuel pump primes, then go high until the engine starts, then go low again while running. The ECM controls that so there's a wiring problem (or the ECM isn't functioning) if it doesn't. The Y/R is the line to the fuel pump. It is monitored by the ECM and the service manual statement refers to what's happening on it. Note that the Y/R lead should behave the same at the fuel pump. O/W also provides power to the ECM and can be checked at the dealer mode connector, ignition coils, and fan relay.

Also see 4-79 & 4-80 in the service manual.
I will follow your guide-- I am breaking my head because it was running great so it makes me worried the Battery Charger caused something.
 

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ST4 Buggy Rail 05 GSXR 1000
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Discussion Starter · #13 ·
BillV
I went to basic last night reading through manual and schematic- I recheck power to pump relay - ignition on I get 12v to O/W and Y/B - I pulled the relay and ran 12v on trigger prongs like manual says and I can here a light click but no continuity on pump side prongs.. I pulled the fan relay and tested that one same exact scenario so I ordered 2 relay to start waiting for Amazon to deliver- I did find a W/B wire that has a bare end but I couldn’t find where it plugs in - I found in schematic that the ECM #1 on black plug is same wire and that goes STVA so will be chasing that but I don’t believe that is cause- I will run continuity to test wire and then look at STAV if it still has it or disabled?
 

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Discussion Starter · #14 ·
BillV
I went to basic last night reading through manual and schematic- I recheck power to pump relay - ignition on I get 12v to O/W and Y/B - I pulled the relay and ran 12v on trigger prongs like manual says and I can here a light click but no continuity on pump side prongs.. I pulled the fan relay and tested that one same exact scenario so I ordered 2 relay to start waiting for Amazon to deliver- I did find a W/B wire that has a bare end but I couldn’t find where it plugs in - I found in schematic that the ECM #1 on black plug is same wire and that goes STVA so will be chasing that but I don’t believe that is cause- I will run continuity to test wire and then look at STAV if it still has it or disabled?
My Question to continue testing before I get my new Pump and Fan Relay- If I open switch and get 12V to O/W and B/Y on Pump Relay once I start cranking should the Y/B wire drop to 0 volt or lower than battery? I am trying to test if I need to order a new ECM-- I read on BillV comment on the forum someone that had the same issue with jumping their bike with a car running. The only issue compared to mine is he had CHECK on LCD panel I have F1 with blinking oil light. Just want some direction to see If I order an ECM also
 

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Discussion Starter · #15 ·
C41 is an issue with the fuel pump relay. Per the service manual:
No voltage is applied to fuel pump although fuel pump relay is turned ON, or voltage is applied to fuel pump although fuel pump relay is turned OFF.

That reeks of a faulty relay or, more likely, a wiring issue. Assuming that you have the cooling fan, try swapping its relay for the fuel pump (they're the same part). If that doesn't do anything, start measuring voltages. R/Bl should always be 12 V. There's a fuse or wiring problem if not. O/W should be 12 V when the ignition and RUN switches are on. There's a problem with the switches, ignition interlock relay, or wiring if not. Y/B is the relay control line to the ECM. It should go high (12 V) at first, then go low while the fuel pump primes, then go high until the engine starts, then go low again while running. The ECM controls that so there's a wiring problem (or the ECM isn't functioning) if it doesn't. The Y/R is the line to the fuel pump. It is monitored by the ECM and the service manual statement refers to what's happening on it. Note that the Y/R lead should behave the same at the fuel pump. O/W also provides power to the ECM and can be checked at the dealer mode connector, ignition coils, and fan relay.

Also see 4-79 & 4-80 in the service manual.
Just wanted your guide Bill as I see you have helped others- I posted some questions on keep diagnosis going — let me know before I purchase ECM I might not need
 

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If I open switch and get 12V to O/W and B/Y on Pump Relay once I start cranking should the Y/B wire drop to 0 volt or lower than battery?
I believe that's what he said here.

It should go high (12 V) at first, then go low while the fuel pump primes, then go high until the engine starts, then go low again while running.

Have you checked for 12v on the R/Bl wire? ( Red probe on R/Bl and Black probe on Batt Neg.)
 

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W/B is also a lead from the brake switches to the brake light. Perhaps you only have one brake system while the bike had two independent systems with a common light. You could check the W/B lead from the ECM to the STVA but I'll bet that your cut lead is the brake light signal. It's hard for me to believe that two essentially independent relays failed at the same time. Something else is going on. Y/B is the relay control line from the ECM. It will be 12 V when the relay is open (fuel pump stopped) and near 0 V when the relay is closed (pump running). All that assumes that there's 12 V on the O/W lead. The ECM gets 12 V power from a B/Bl lead (always hot) and the O/W lead (switched). The O/W also runs to the dealer mode connector. You can check that the ECM is getting power by probing that lead at the connector. You can also do a simple check on the ECM by checking the R lead on the nearby black eight pin SAP connector (O/W must be hot). It should be 5 V. The ECM can fail but that's unusual. When the ignition and engine stop switches are turned on and O/W goes to 12 V, the Y/B lead should very briefly also go to 12 V until the ECM is running. At that point it will pull the Y/B low for three seconds as it primes the pump. Then it will let the voltage go high again until it senses that the engine is running, at which point it will pull the Y/B low again.
 

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ST4 Buggy Rail 05 GSXR 1000
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Discussion Starter · #18 ·
W/B is also a lead from the brake switches to the brake light. Perhaps you only have one brake system while the bike had two independent systems with a common light. You could check the W/B lead from the ECM to the STVA but I'll bet that your cut lead is the brake light signal. It's hard for me to believe that two essentially independent relays failed at the same time. Something else is going on. Y/B is the relay control line from the ECM. It will be 12 V when the relay is open (fuel pump stopped) and near 0 V when the relay is closed (pump running). All that assumes that there's 12 V on the O/W lead. The ECM gets 12 V power from a B/Bl lead (always hot) and the O/W lead (switched). The O/W also runs to the dealer mode connector. You can check that the ECM is getting power by probing that lead at the connector. You can also do a simple check on the ECM by checking the R lead on the nearby black eight pin SAP connector (O/W must be hot). It should be 5 V. The ECM can fail but that's unusual. When the ignition and engine stop switches are turned on and O/W goes to 12 V, the Y/B lead should very briefly also go to 12 V until the ECM is running. At that point it will pull the Y/B low for three seconds as it primes the pump. Then it will let the voltage go high again until it senses that the engine is running, at which point it will pull the Y/B low again.
She is running again— I went on testing all that was told Bill but I just went back to seeing all the wires and testing the relay by the manual— both fuel pump and fan relay click but no continuity— so Yesterday one relay came in late so I ran to test it first which when I added 12v it clicked louder and had continuity— I plugged her in and ( dear baby Jesus) it’s alive —- Thank you all
 

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She is running again— I went on testing all that was told Bill but I just went back to seeing all the wires and testing the relay by the manual— both fuel pump and fan relay click but no continuity— so Yesterday one relay came in late so I ran to test it first which when I added 12v it clicked louder and had continuity— I plugged her in and ( dear baby Jesus) it’s alive —- Thank you all
 
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