3,000 rpm idle. 2008 wee

[Hondaman]

Is this the bike you've just bought that had a link to on here last week?
If so, were you told about it revving high?
Either way, it may be worth having a gentle word with the po.

[greywolf]

The service manual sets the following reasons for a too high idle.

ISC valve circuit open or shorted
to ground
Air passage clogged or leaking
Power source circuit open
ISC valve is fixed to full open
Disconnected ISC valve hose
ISC valve hose connection
ISC valve PRE-SET is incorrect

Start at page 13-35 in the service manual for test procedures. Many of the tests can be done without an SDS computer tool.

[garth]

Right, following the manual and as far as I can tell I have no continuity between the connections on the valve, eg, it's knackered.

I contacted the PO, he said there was no problem previously. Didn't seem the type to lie.

[Rich:-)]

So... just out of interest, did the bike do this from the moment you collect it or during the ride home?

[garth]

Difficult to say. When I rode off, I *think* it was OK. A mile down the road when I slowed for a junction I noticed it was idling high, then after that I noticed the light.

I've ordered a second hand ICS valve. I'll test before I fit.

[Rich:-)]

One thing I've noticed about mine is that the revs don't seem to change with engine temp, bikes often run faster when on choke, even injection ones but the Wee is very well mannered in that respect. No doubt running richer when cold but still revs about the same on idle.

Just odd that this problem developed in a short time frame, during the ride home... but I guess some faults develop slowly over time and others just appear without warning.
Could just be very bad luck.

[greywolf]

There is a fast (cold) idle linkage. If it is cold enough outside, the engine may idle between 1800-2200rpm when first started.

[Rich:-)]

Ah, obviously I've not ridden when it's been cold enough.
Fair weather only for road bikes!

[garth]

Right, update.

I've changed the ISC.

The bike now idles at about 1200, it rides fine. But the C40 code is still showing. I've tried the idle reset (on,off,dealer jumper) and it doesn't clear it.

I'm running out of ideas and patience, is there a way of clearing the fault code?

[garth]

Alternatively, if the ECU is still detecting a fault, and flagging up the C40 code, why the bloody hell is it running fine?

All the wiring, hoses etc look fine.

[greywolf]

It's idling a little low. My best guess is the new ISC valve isn't right either. The air passage may be clogged though.

[garth]

If I took it to a dealer, with the official Suzuki tool, would they be able to diagnose any further or reset it?

[garth]

Also - should the idle change from cold to hot? It stays roughly the same. It's about 6 ambient here.

Surely it should be a case of resetting it, but I have no idea why this won't work.

[greywolf]

The only reset is the one I already provided. A dealer with an SDS tool can read past codes and delete them, but you have an active code due to a low idle speed. Your best bet is probably to complain to the place you bought the ISC valve from that it isn't properly setting the idle speed.

The bike does have a fast (cold) idle circuit that will raise the idle to 1800-2200rpm until the engine gets a little warmer. That may need adjusting though many people don't see that unless it is very cold. It will have no effect on warm idle though and that is where your problem lies.

[garth]

I may have just had a breakthrough.

I took apart both valves, and noticed they were at different levels. This is inkeeping with different idle rates, one allowing more air through than the other.

I then attached both halves to see how they react with ignition on, and resetting the idle. Both did nothing.

I then tested (again) the wires from the ISC plug to the ECU. It seems I have a faulty wire intermittently between A and 58.

Tomorrow I'll replace the wire and hopefully, it will allow me to reset. Then fingers crossed my c40 error will clear.

[greywolf]

It would figure a continuing problem after replacing a part would mean the part was not the problem. I didn't think that here because of the problem exhibiting different characteristics but that makes sense.

[garth]

Fixed. Ran a new cable.