08 Cold Idle and Oil Level Light

I encountered a problem while I was on vacation which might be related to discussions on this forum, but I have a difference I have not found so started a new thread.

In the middle of a 4,000 mile trip, my 2008 experienced very rough cold starts. Very slow idle, rough, engine dying without applying some throttle. And the low oil level light would come on. After getting the bike warmed up, it ran normally. The oil level light would not clear, however, unless the ignition was turned off and the bike re-started. The oil level, cold, is just below the top of the sight glass while on the center stand.

The problem continues, though off and on. Sometimes it starts up on fast idle, warms up and everything is fine. Other times, it will run very slow and rough until it is warmed up. And other times, this afternoon for example, it started on fast idle, began idling down as it warmed up and continued idling down to about 500 rpms at which point it barely was running. Restarted it and it ran normally. In every instance where I have started it cold and the fast idle was not achieved, the oil level light has come on and will not go out unless the ignition is switched off.

Is the oil level light on some type of holding circuit? It crops up consistently with the cold start up problem but it is very hard to understand how it could even be related.

I have not attempted to disassemble the panels to get to the coolant lines on the wax motor but it seems if they were plugged, they would be plugged and the problem would not be intermittent.

FYI: Normal idle is 1000 rpms, high idle is about 1500. My idle adjustment (for warm idle, right side of the bike) is adjusted all the way in to achieve the 1000 rpm idle, has been that way since I bought the bike.

Currently, bike has 92,000 almost completely trouble free miles on it.

Any thoughts appreciated. Working on locomotives in more my forte than motorcycles, so this has left me completely stumped.

I didn't think that the low level sensor was connected to anything other than the light??? I almost never came on for my '07 (maybe twice in 185,000 miles). It comes on semi-regularly on my '11 but only when engine is cold and typically under high(er) acceleration or uphill. (Never while idling, only when moving) Never noticed anything changed with respect to performance - before, during or after. The light always shuts off by itself but may take a couple of minutes and doesn't come on again as long as the engine stays warm.

Maybe the linkages on the wax motor are the issue - jamming (or other mechanical issue) rather than plugged lines. Certainly sounds like your problem could have something to do with the fast idle circuit. Good luck!!

RadioHowie did some work on the wax motor on his GenI a number of years ago...

https://www.fjrforum.com/forum//index.php/topic/122016-further-details-on-fast-idle-system/?hl="wax+motor"

Adjusting the fast idle is not easy.

I have vague recollections of adjusting mine.

I believe I had to remove the throttle bodies

to gain access.

In the end it was worth the trouble as the fast

idle is once again working properly.

I had a similar problem on my '08 at similar mileage.

Read this posted elsewhere.

Hopefully it helps.

Further to what John d posted, I had a similar running issue but it generated a fault code which helped with the diagnosis (Fault Code 14). It had nothing to do with the oil level sensor. Don't know if it is a possibility in your case but here is the thread I started when I encountered this. (I am not the only one!!) I have no idea if this could occur without generating a fault. In any case, it is pretty easy to check once you are under the tank. I would definitely do this check before yanking the air box and throttle bodies to look at the fast idle circuit!!

https://www.fjrforum.com/forum//index.php/topic/170314-fault-code-14-gen-ii-solved/

Thanks for the responses. I have yet to check the MAP lines and sensor but have made another discovery. I just checked the throttle body sync with a Carbtune. All showing about 220 mg/hg. Adjusted up to about 240, which is max I could achieve. (I had adjusted all TB screws out 1-1/2 turns to begin syncing and adjusted in from there to achieve max vacuum). In the process of doing this, I discovered that my idle adjustment cable is seized, cannot turn to adjust idle. Just looked this part up on Bike Bandit and discovered there is no part number for it or the "body" that it attaches to (don't know the name of the piece the cable connects to). Anyone had this problem before?

Cable connects to what appears to be some sort of valve. Is it servicable? Replaceable?

HPD said:

...Cable connects to what appears to be some sort of valve. Is it servicable? Replaceable?

Click to expand...

I suspect this is not sold as a separate item, but is part of the fuel rail assembly. That's a guess on my part.
I would think that it would be well worth while your attempting to service it, provided you are sure it really is jammed. From memory, turning it was both stiff and spongy.

Image below taken from the 2006 service manual.



Removing the fuel rail is relatively easy, a few pictures around here may help (taken during a cruise control installation on my 2010, I don't think there's any significant difference over these years).

One and a half turns out as a starting point may be too far. Try three quarters to one turn out to begin with. If too far, you run out of range on the idle adjust. Probably nothing wrong with the idle adjust. Don't wory too much about absolute vacuum readings.

At this point, since your idle adjust mechanism is seized up, I would just get your idle adjusted to spec by opening and closing the four air screws that you use to balance the idle vacuum while maintaining good balance. The idle adjust mechanism on second Gens is just another air bypass circuit that performs a similar function as the 4 air screws.

You might want to attempt the RDCUA TBS procedure first as that will help maintain balance at higher rpm where the air screws only really affect balance near idle speed. The gist of the RDCUA TBS is to close down all 4 air screws fully and balance the vacuum with the mechanical linkage adjustment screws. This ensures that the throttle butterflies are synchronized before you go opening the 4 air screws up the same amount (3/4 turn) and balancing while also setting idle speed.

I dont see any possible way for the oil level light to be related.

Thanks again to everyone for your help! Much appreciated. I have had so little trouble with this bike that I have not had to learn too much in-depth about the fuel and air systems, so catching up now.

I do not see how the oil light can be related, though I have no explanation for its behavior. For now, I am not too worried about it.

The idle adjustment knob is definitely seized up. Idle is close right now, about 900 rpm, so not a major concern for the moment. I am planning on checking all of the vacuum lines for blockage and will try and get around to pulling the throttle bodies out for inspection and cleaning. Hard part is finding time to do it. (Pics provided by Mcatrophy were fantastic, thanks for all the effort!)

Fred W: I read about the procedure you outlined. Very interesting. Might give that a try when everything goes back together.

I will post anything I find as the work progresses. Thanks again for your inputs. I have to say, the current little hiccup aside, this bike has performed way beyond anything I could have expected. My word, what a motorcycle!