Suzuki SV650 Riders Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
2nd gen '08. So this started a month and a half ago with a no-start condition which I finally traced to several things. I had to replace the ignition fuse. Then, the fuel pump was not priming.
I took out the fuel pump relay and tested it according to the service manual to make sure that it was still working, which it was. However, when installed, I would never hear the clicking and it would not pass power to the fuel pump. I found out that the yellow/black wire coming from the ECM to the relay is supposed to drop to 0 volts for a few seconds when starting the bike, and then return to 12 volts the whole time the bike is running. (It's a little bit counterintuitive because for there to be a 12 volt difference on the two smaller wires on the fuel pump relay, instead of them both being a zero and one raising to 12, they both start at 12, and this yellow/black one lowers to zero which provides the voltage difference which opens the relay which allows the other 12 volt to push through to the fuel pump).
For whatever reason, this yellow/black wire from the ECM never would drop down to zero volts in order to open the relay. I have no idea why. I checked all my sensors.
Anyway, the solution is that I snipped the yellow/black wire, about an inch or two from the fuel relay, and connected it directly to the ground. Started right up!!!! Weeeeekslong saga coming to an end.
The only downside of this approach that I can see is that, when you turn on the ignition and flips the kill switch to on, instead of the fuel pump running for just three seconds, it will run forever. So, you need to start the bike reasonably quickly after that. The other downside is that in a really bad collision, the fuel will continue being pumped until you flip off the kill switch.
Besides these downsides, does anybody else have any idea about why this might not be an acceptable long-term solution, or why the ECM might not be dropping the voltage on the yellow/black wire accordingly?
I hope that my particular situation may serve somebody in the future who experiences the same problem.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #2
Does anybodyh have any idea why the ECM might not be telling the fuel pump relay to turn on? That's what I traced it to. It's for sure something with ECM or some sensor that would tell it not to turn the fuel pump on. However, all of the sensors that are required in order to have the ignition fire, are totally functional, so it's hard to imagine that the ignition would fire but the fuel pump would not.
 

·
Super Moderator
Joined
·
8,604 Posts
... Besides these downsides, does anybody else have any idea about why this might not be an acceptable long-term solution, or why the ECM might not be dropping the voltage on the yellow/black wire accordingly?
- The ECM is not controlling Y/B because the fuel pump control transistor inside the ECM has failed. This can happen if accidentally touching the wrong fuel pump relay wires while ignition power is on. Do you have an FI error showing?

- The main downside to bypassing the ECM as you mention is the fuel pump will run all the time.

- The best solution is buy a replacement ECM. Check here at Mad8VCycles.com. Mad is a member here and excellent seller, great service, great prices. If no luck there then check eBay. Be sure to match the part number as many of the eBay listings are wrong. For sure 2003-2006 ECMs are different from 2007+

Good luck and nice job debugging the problem. In the future just log on to SVR, would have saved you Weeeeks of time. ?
 

·
Registered
Joined
·
5 Posts
Discussion Starter #4
Haha, thanks. I really appreciate the response. Actually I have been constantly searching on SvRider over these few weeks and it has been a great source of help, but I was unable to find anybody who had the exact same set of problems as me. I've actually seen your name come up many times and even considered messaging you directly, thanks for all your responses to the other posters that helped lead me to this solution.
I'm curious to know more about why you might think that I need a new ECM as opposed to the makeshift solution I came up with. Cheers.
 

·
Super Moderator
Joined
·
8,604 Posts
I'm curious to know more about why you might think that I need a new ECM as opposed to the makeshift solution I came up with. Cheers.
Hardwiring the fuel pump relay will allow the bike to run but ECMs are cheap, might as well fix it right.

Another consideration, every failure of this type I have seen triggers the C41 error code. When an FI error is active the ECM may go into "fail-safe-mode" which can select default timing and fuel maps. The bike will still run but not ideal.

Is your bike showing an FI error?
 

·
Registered
Joined
·
5 Posts
Discussion Starter #6
Hardwiring the fuel pump relay will allow the bike to run but ECMs are cheap, might as well fix it right.

Another consideration, every failure of this type I have seen triggers the C41 error code. When an FI error is active the ECM may go into "fail-safe-mode" which can select default timing and fuel maps. The bike will still run but not ideal.

Is your bike showing an FI error?
Yes, indeed, it was showing the FI error as well as the c41 code.
I can't remember, after the modification I made when I was riding yesterday, whether it was still showing the code I was so happy to be on the bike I didn't notice.
The symptoms which led up to this, 2 months ago, was that the bike would spontaneously die when I was idling at a red light. Not sure if that helps solve a piece of the puzzle or not. But it sounds like the kind of thing I could happen as a result of the fuel pump turning off!
 

·
Super Moderator
Joined
·
8,604 Posts
... Do you know if they are year specific? ecu 2003/2004 2g sv650 f8t95773 mgt062
ECMs from 2003 thru 2006 will NOT fit your 2008.

You need an ECM from 2007+
If your bike is USA or Canada, the part number is : 32920-17GC0 or 32920-17GC1, either number will work, C1 supersedes C0.

If your bike is California, the part number is: 32920-17GD0.

Be sure to verify the exact part number with the seller before purchase.

It is possible the USA/Canada ECM might work in a California bike or vice-versa, it might just be an emission tuning thing, but I do not know for sure.
 
1 - 8 of 8 Posts
Top