SV1000 Turbo Update

The bloody Turbo is still causing me some problems, but I’ll not be beaten, I’ll get it in the end (Or it’ll get me!!!) I am still fiddling with the Fuel Pressure Regulator trying to get a good setting that lets the bike run off boost and produces power on boost. Currently I have a setting that lets the bike run but the boost isn’t producing real power. I think it is running really rich, I will be having another fiddle this weekend if it is dry and not too cold!!!

Another fuelling problem I have with this bike is that the Fuel Injection fault light comes on and the bike goes into simplified fuel injection mode. I believe that this is because the Intake Air Pressure (IAP) sensor sees more than 7psi of boost. Though I am not 100% sure if it its that the sensor sees 7psi or that it sees 7psi for too long. I am working on a way to sort this, however I don’t think I can use the method used on say a Hayabusa to avoid the fault. On the Hayabusa they put a couple of one way valves teed off the vacuum feed to the IAP, then it can see all the vacuum it wishes, however once the boost kicks in it bleeds off through the one way valves. However on the K5 and newer SV1000’s (and guess which one I have, yep a K5) they decided to change how the ECU (Electronic or Engine Control Unit depending who you ask) an early SV1000 like lots of Suzuki’s, including the Hayabusa got the engine position from a camshaft sensor. It is very important that the ECU knows what the engine is doing and where it is in it’s cycle so it can fire the spark at the right time and squirt the fuel into the engine at the right time. For some reason (answers on a postcard to Why Did Suzuki Do it?) Suzuki changed the set up on the K5 so that there were two IAP’s one for each cylinder and then they used the output from these IAP’s to judge where the engine was in it’s cycle.

Because the IAP’s are being used as sensors I don’t think it would be a good idea to bypass them as the ECU will basically loose count of where the engine is and fault out in a different way. So what I am going to try and do is let the IAP see the boost but hi-jack the reading it is sending to the ECU and cap it at the maximum reading that the ECU is expecting so it should operate 100% as it should even when the bike is producing boost. Well that’s the theory anyway, we’ll see what happens once the bits of electronic maguffin that I’ve ordered turn up.

I have been sitting back and thinking about the electric fault that I am trying to sort. I think I am going to try and attenuate the input to the IAP rather rather than play with the output. This means that I only have to have one electric control box on the input line rather than one on each IAP. Hopefully this will be a more elegant solution, but if it doesn’t work I have another unit in reserve so I can go back to plan A. I need to get a few other bits sorted before I can try this out as the bike is currently in a lot of parts on the bench while I sort out some other bits and bobs.

About The Author


Ambitious Amateur Mechanic, with a slight (OK not slight) Suzuki bias