Hard to start and keep running when cold
|Subject: Hard to start and keep running when cold Mon May 13, 2019 9:21 pm|| |
I've been searching the Internet, but I haven't found any instances which match what I'm experiencing. My 2013 WR, which I've had since new, has always fired right up without having to touch the throttle. The only exception was when the stator went out and drained the battery, but that was fixed in the recall a number of years ago. Two weeks ago, the bike did great on a test ride, which was part of our prep for a trip to Sedona. A week later, after trucking the bike to Sedona, it didn't want to start. No changes were made in between.
The fuel pump makes the normal "priming" sound when the ignition is turned on.
The starter seems to be turning the engine over normally when the button is pushed.
The engine will act like it wants to start, but it can't quite get going if you don't give it throttle.
If you play with the throttle while cranking, the engine can be made to start, but it will die if you try to let it idle too soon.
If you feather the throttle for about 15 seconds while the engine is running, it will be able to idle.
Once warmed up, the bike runs great. The power seems normal, it can run at WOT without missing a beat, everything is cool.
It is still necessary to play with the throttle while starting even when the bike is warm about 30% of the time.
The following stored codes are present:
19 - Sidestand Switch - Open circuit in the wire to the ECU.
21 - Coolant temperature sensor - Open or short circuit detected.
30 - Lean angle sensor - Latch up detected. No normal signal received from the lean angle sensor
46 - Vehicle system power supply (Monitor Voltage) - Power supply to the ECU system relay is not normal.
Codes 19 and 30 can prevent the engine from starting, but I don't think this is the case since working the throttle results in the engine starting. Also, these could be left over from when the battery died when the stator failed.
In diagnostic mode, I verified that the throttle position values are correct and that the lean angle sensor is reading correctly. I also verified that the sidestand and clutch switches are working properly. I replaced the spark plug and verified that the air filter is clean, plus there are no obstructions in the airbox.
While cranking at idle, there is a slight gas smell coming from the end of the pipe. The old spark plug was wet and smelled like gas when I removed it.
I'm not sure where to go from here. We're back from Sedona, so I have time to wrench on it. Any thoughts or advice are most welcome.
|Subject: Re: Hard to start and keep running when cold Sat Jul 20, 2019 11:47 am|| |
I figured out what it was, so I might as well post it here. A leakdown test indicated 75% loss. From the sound of it, most of the air was coming from the intake valves, but some was coming from the exhaust valves as well. The crankcase and radiator were relatively quiet.
A valve check showed 3 of the valves right in spec, with one of the intakes so tight I couldn't even get the smallest feeler gauge through it. I ended up using a shim that's .3 mm thinner in order to get it back in spec. This same valve was way too tight a year ago, so it's obviously on its way out.
With the cam shafts off, leakdown was still indicating a 60% loss. So there are two issues - one valve that's about to launch and the others which don't seem to be sealing very well.
I put everything back together, and the bike starts and runs now. I plan to sell it cheap to someone who either wants a project or is interested in having it fixed.
|Subject: Re: Hard to start and keep running when cold Sat Jul 20, 2019 5:01 pm|| |
Thanks for posting what you found, that kind of thing can be invaluable to someone else down the road.
|Subject: Re: Hard to start and keep running when cold Sun Jul 21, 2019 12:12 pm|| |
Glad to do it! I'm always grateful when someone posts the solution to the problem, so I wanted to close the loop on this one. I'm still mystified as to why the valves gave up the ghost in 14,000 miles. I always run premium gas, keep the air filter clean, and change the oil frequently. Maybe being a fat guy on a 250 just wasn't a good idea.
|Subject: Re: Hard to start and keep running when cold Sun Jul 21, 2019 4:55 pm|| |
- VW_Lee wrote:
- Glad to do it! I'm always grateful when someone posts the solution to the problem, so I wanted to close the loop on this one. I'm still mystified as to why the valves gave up the ghost in 14,000 miles. I always run premium gas, keep the air filter clean, and change the oil frequently. Maybe being a fat guy on a 250 just wasn't a good idea.
Yeah, that seems out of character from what I've read on these bikes, especially considering you are just past halfway to the "official" valve check mileage of 26k.
|Subject: Re: Hard to start and keep running when cold Sun Jul 21, 2019 6:56 pm|| |
Curious about your air filter maintenance habits.
|Subject: Re: Hard to start and keep running when cold Sun Jul 21, 2019 11:47 pm|| |
You're right, this does seem to be out of character based on all the experiences I have read and what friends have experienced. The valve saga started last year when I heard the cam chain rattling at startup. I read about the defective cam chain tensioners, so I bought a new one and had fun installing it. Since I was already right there, I checked the valves. All but one of the intakes were in spec, and the one which was out was out quite a bit - .06 mm (the spec is .13 - .20). I set it to .15, and it only took 1,000 miles for it to close back up (and then some) completely.
I would clean the air filter whenever I could see a slight haze of dust on the outside of it. This could be as often as after every ride. The inside part of the filter and the throttle body always looked clean. I use UNI foam filter oil in the bottle, not the aerosol. I put white lithium grease on the sealing surface and make sure it's properly seated. Is it possible I cleaned the filters (I switched between 2 elements) too often? Maybe the foam broke down (although this isn't evident upon visual inspection).
|Subject: Re: Hard to start and keep running when cold || |
Hard to start and keep running when cold