C28 fault

[muzza55]

g'day again, never ending battle to get this bugger right.

Everything was working perfect, bike was left in rain overnight, shouldn't hurt surely,
anyway on starting the next morning revs all over the place and FI comes on and stays on, was 400 klms from home so road it home easily down the motorway, never missed a beat, FI on all the way, parked it up and got pissed.
Next morning started it up, FI on checked the fault code and see C28, OK STVA, read all posts on subject, changed out STPS, no change, checked movement of STVA shaft, knackered, stiff and jerky.
So I have changed throttle bodies with a good STVA, same result C28, changed fuel injection wiring harness, adjusted throttle bodies, adjusted TPS and STPS, still the same. I let the bike run to warm up and felt in the air box as to the position of the STVA's and they are still fully closed, FI still showing.
I'm stumped fellas any ideas besides a box of matches ?
slightly miffed muzza.

[Blubber]

My guess : Probably corrosion in the lower part of the ignition  switch.

[muzza55]

thanks for that idea mate, I do recall reading a few unrelated posts that the ignition switch can cause all sorts of issues and fault codes, I'll pull and clean up tomoz, thanks again.
muzza.

[Blubber]

thanks for that idea mate, I do recall reading a few unrelated posts that the ignition switch can cause all sorts of issues and fault codes, I'll pull and clean up tomoz, thanks again.
muzza.

Indeed. I cleaned mine years ago and havent had any "ghost" errors anymore.

Difficult part was getting the security Torx out. My cheap multipurpose bit set deformed pretty quick due to the threadlock Suzuki used.

I used a coarse 3m scotchbright pad on rhe copper bits and lubricated with acid free petrolium jelly. If you were wondering

[Hooli]

When you say you adjusted everything, did you set both TPS & STPS to the correct base values? The ECU uses a combination of these to control the fast idle amongst other things & it'll cause a C28 error if they are too far out of spec.

Setting the STPS needs to be done with the bike warm & the ignition on so the secondary throttles are in the correct place.

[muzza55]

g'day Hooli, yes mate I have adjusted both senors to the correct value, even when the bike has been running for 5 minutes the STVA doesn't seem to move the butterflies at all, got me stumped . i will get the meter out today and start checking all the wiring harness between the throttle bodies and ECM, has to be something wrong in there somewhere,
muzza.

[Hooli]

I'd agree with you on wiring as you've already tried throttle bodies.

[Snapey]

There might be a problem with the new set of throttle bodies so just for the hell of it I'd be fixing the old STVA and putting that set back on.