Honda NC700x starting issues

[fazer69 1]

Hi,

I've just looked through the forum to try and find bikes with the same issue I have, but have not been able to find anything, so good news that it's not a common fault with the NC, but bad news as it's a hard one to pin down!

 

My UK NC700x 2012 with 10,000 miles, has struggled to start at times and it looks like it's getting worse.

Everything works and cranks over strongly, but the engine will not catch and start. It was doing it before a recent service and is still doing it.

I've replaced the battery, cleaned the terminals and I've had a mechanic look at it and he cleaned all connections within the starting loop.

 

One day in the life of my NC; started fine in this morning, 10 min ride and park at the supermarket, struggled to start at the supermarket and only seemed to start when I decided to open the throttle a bit. Parked at work, started fine to come home from work, got home switched engine off back on again and it took 6 or 7 hits of the button to start again.

 

Slight theory, but I don't know what to do with it: I have a Triumph Street Triple too and when starting the FI races and drops till it's happy (kinda choke work), the NC doesn't do this, when it starts it goes straight to a normal tickover.

I'm thinking a sensor somewhere is not doing it's job, but I don't know which or where.

 

I'm on the verge of taking it to a main dealer to connect a diagnostic tool to her and point and giggle at something working as it should.

 

Any advice would be greatly received.

 

 

 

  

 

[embee 7,288]

First question, do you hear the fuel pump run when you turn the ignition on?

Does the HISS light come on for a few seconds then go out when you turn on the ignition?

When it does start, does it run in a strong/stable manner or is it coughing/stumbling etc?

Is your fuel economy OK?

 

[fred_jb 10,265]

If it is turning over strongly, then it can only be one of three things - fuel supply, air supply, or correctly timed and sufficiently strong sparks from the ignition system.

 

I guess it could be a temperature sensor as you have already surmised, as if it doesn't know whether the engine is hot or cold this might making starting harder.   It won't necessarily need to set a higher tickover and richer mixture when trying to start from cold in the summer as it shouldn't need much help when it is warm outside.  I know my NC had very apparent higher tickover when cold, to the extent that I could be taken by surprise by the lack of engine braking this caused  until it warmed up.

 

On the other hand if it is failing to start when warm, and benefits from opening the throttle, that might suggest it thinks the engine is cold when it is warm and is enriching the mixture unnecessarily and choking the engine - I remember years ago old cars that were reluctant to start and had flooded the engine with excess petrol would sometimes start if turned over with the throttle wide open.

 

The other thing worth looking at might be the plugs, but I don't think they should need changing at only 10,000 miles, though I'm not sure what the official figure is.

 

OK - I'm sure more knowledgeable and better mechanics than me will be along shortly!

 

EDIT:  Oh good I see embee is now on the case!

Edited July 28, 2017 by fred_jb

[fazer69 1]

8 minutes ago, embee said:

First question, do you hear the fuel pump run when you turn the ignition on?

Does the HISS light come on for a few seconds then go out when you turn on the ignition?

When it does start, does it run in a strong/stable manner or is it coughing/stumbling etc?

Is your fuel economy OK?

 

Hi, thanks for replying.

Just tried her and hiss comes on, fuel pump runs and the b*tch started first stab of the starter.

I don't know really about the fuel consumption as it's not really something I keep an eye on, sorry.

[trisaki 2,029]

My 700x sometimes does something similar   let us know how it goes   could be looking at the same problem  by the way mine has done  11000 m 

[embee 7,288]

I'm just thinking of the issue I had. I apologise for keeping referring to it, but it's such a basic thing that it's worth checking out. It's cropped up again in this thread  as a possible reason for random cutting out of engine http://www.nc700.co.uk/index.php?/topic/15979-dct-ignition-cut-out/

 

On mine the connector for the kill/start switch which is located about a foot or so away from the switch block (trace the wiring harness to find it) had a couple of tarnished pins which essentially stopped the power getting to the switch. As far as the bike ECU was concerned the kill switch was off, even though it was physically on. Depending on what pins are tarnished, it'll either get no power at all so no pump and no starter, or it might get power and the starter works but no pump, or it could get pump but no starter etc. Also being tarnished, it can be intermittent depending whether it's been moved by the wiring nudging it when the bars are turned etc.

 

Mine is an early build 2012 NC700 Integra. There could possibly be a batch issue with harnesses and pins now beginning to show up? Since carefully cleaning these pins and applying contact cleaner and working the connector in/out a few times, it's not done it again. If I ever get it happening again I'll consider replacing the connector with a new one.

[fazer69 1]

11 minutes ago, embee said:

On mine the connector for the kill/start switch which is located about a foot or so away from the switch block (trace the wiring harness to find it) had a couple of tarnished pins which essentially stopped the power getting to the switch. As far as the bike ECU was concerned the kill switch was off, even though it was physically on. Depending on what pins are tarnished, it'll either get no power at all so no pump and no starter, or it might get power and the starter works but no pump, or it could get pump but no starter etc. Also being tarnished, it can be intermittent depending whether it's been moved by the wiring nudging it when the bars are turned etc.

 

Thanks, job for the morning 

[Tonyj 6,907]

If the timing was out would it run rough all the time 

[fazer69 1]

28 minutes ago, Tonyj said:

If the timing was out would it run rough all the time 

Mine runs perfect once started.

[fazer69 1]

She's booked into the main dealers next week

[embee 7,288]

Just reading through your first post again, does it start straight away when cold but not when warm/hot, or is it random?

 

If a sensor was faulty or disconnected (AIT sensor in air filter housing etc) it ought to show a fault on the MIL (Maintenance indicator or "check engine") lamp on the dashboard. If it's a temperature issue then the connections to the air intake temp in the airbox and the coolant temp sensor in the thermostat housing are first things to look at.

[fazer69 1]

21 hours ago, embee said:

Just reading through your first post again, does it start straight away when cold but not when warm/hot, or is it random?

 

If a sensor was faulty or disconnected (AIT sensor in air filter housing etc) it ought to show a fault on the MIL (Maintenance indicator or "check engine") lamp on the dashboard. If it's a temperature issue then the connections to the air intake temp in the airbox and the coolant temp sensor in the thermostat housing are first things to look at.

 

At first I thought it was random, but now I'm leaning towards hot starts are the issue.
I haven't used her for a week as using my other bike, but Saturday after a week, she started fine, rode to town (10 mins), wandered round town (20 mins) and she started fine.
Rode to supermarket for petrol (10 mins) and she started fine. Rode home (10 mins) turned off and tried to start again immediately and she took 6 or 7 attempts to start.

There is no indication on the engine check to suggest anything is wrong.

I've owned her for around 4 years, so I'm not too annoyed as I've never had a problem with her before. I've never owned a bike this long either in 40 years of riding   

[fazer69 1]

Well for anyone following this topic, she seems to be back to normal!

Main dealer charged me £140 and found nothing and made no recommendations, as it behaved when they had her!

Next day took 6 to 8 pokes to get going.

Decided to soak her in WD40: Solenoid, plug caps, leads, starter motor, battery and anything I could get at.

Next day she was better, 3 pokes of the starter maximum.

I also bought a good second hand solenoid for £14, fitted and she starts 1st poke now and I'm very happy to have hopefully found the issue.

Whether it was the solenoid or just moisture around it I don't know, but I do know the area to pinpoint if it happens again. 

[fazer69 1]

 

Old photo from when I first bought her

Edited August 19, 2017 by fazer69

[embee 7,288]

Hope it's fixed for good.

Just to be absolutely clear, I take it you are talking about the main starter relay/solenoid, not another relay (e.g. fuel cut-off)? Was your bike subject to the recall on the starter solenoid?

[fazer69 1]

4 hours ago, embee said:

Hope it's fixed for good.

Just to be absolutely clear, I take it you are talking about the main starter relay/solenoid, not another relay (e.g. fuel cut-off)? Was your bike subject to the recall on the starter solenoid?

Yes the starter relay/solenoid.

Apparently the CB500 had a recall on the starter relay/solenoid, but not this model as far as I'm aware.

[SteveThackery 3,090]

I'm confused.  Surely a faulty starter relay/solenoid would stop it from cranking.  Fazer69 says it "cranks strongly" but won't fire.  

 

Can a faulty solenoid stop it from firing, even though it's cranking strongly?

[Tex 36,817]

1 hour ago, SteveThackery said:

 

Can a faulty solenoid stop it from firing, even though it's cranking strongly?

 

No.  

[trisaki 2,029]

My Nc700x sometimes when on the side stand  it turns over fine but doesn't fire when put straight up on the main stand  fires up straight  away - if it was the sidestand switch would it turn over ? 

[Tex 36,817]

1 hour ago, trisaki said:

My Nc700x sometimes when on the side stand  it turns over fine but doesn't fire when put straight up on the main stand  fires up straight  away - if it was the sidestand switch would it turn over ? 

 

Yes. The side stand switch interrupts the earth path of the ignition. It works in conjunction with the clutch switch and neutral light switch. For the ignition to function you need one of those three. You need to be in neutral or have the stand retracted or pull the clutch in. Without one of them it will turn but not spark. 

[trisaki 2,029]

So hopefully a dirty contact  on the side stand switch because  sometimes she does fire up quite happily 

[Guest Mac750]

Daughters twist and go is the same , it will crank but if side stand down won't fire . 

[SteveThackery 3,090]

3 hours ago, Mac750 said:

Daughters twist and go is the same , it will crank but if side stand down won't fire . 

 

And my Enfield.  Ridiculous logic - it shouldn't turn over with the side stand down.

[Bigglesaircraft 293]

If my 700X is in neutral it turns over and starts when it is on its side stand.

Edited August 21, 2017 by Bigglesaircraft
Spelling

[DaveM59 1,605]

The starter solenoid is also the tapping off point for the bikes electrics before the engine starts. If it goes high resistance internally, the relay action could still be OK so turning the motor over, but the feed to the fused circuits is compromised and as the starter requires a lot of amperage, leaving nothing left for the ignition. As the power needed to crank will differ almost every time you start, depending on temp, weather etc, the effect will also be different. The ECU won't detect a fault as on initial ignition on test everything is OK.

Once the engine is running the alternator is doing the work not the battery so the feed out of the starter solenoid is not doing much so no performance is lost.