ER6f 2008 Excessive fuel useage 12mpg

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

The ER6 has gained a problem since the rebuild, it is only doing 12 or so MPG.

I've connected it up to an OBD reader and there are no faults.

I've checked the TPS and the voltage is out by 0.2v but the resistance on the actual TPS is within range which points at the ignition.

The exhaust sensor 02 sensor is being changed as it's 50K old but no fault on the OBD.

None of the throttle body sensors are available seperately.

So what do people suggest?

MarJay · But it's British! Joined: 15 Sep 2003 Karma :

Well... I can't be *very* helpful, but my first thought is that it must be something big because a 1-5mpg difference might be an annoyance, a 20mpg difference might cause some concern, but you're talking about a quarter of the fuel range or a quadrupled fuel consumption with that bike... Yikes.

The only thing I can think of is to check connections to any and all sensors on the bike. Sorry, you said it has a new O2 sensor. Have you tested it's resistance? Don't forget that bikes don't actually comply with the OBDII standard yet, so are variable on the results you get from diagnostics.

Apparently there is some property of the engine that needs to be read to meet the official definition of the spec that is difficult on bikes due to the high revving nature of the engines. I suspect this means in practice that the implementation of the spec is variable...
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sickpup · Old Timer Joined: 21 Apr 2004 Karma :

It's a Healtech OBD so compatability isn't an issue.

o2 sensor isn't replaced yet, waiting for it to turn up. Old one is within spec.

With an o2 eliminator it's still rich which again points at the ignition.

Bike normally does 60ish mpg.

MarJay · But it's British! Joined: 15 Sep 2003 Karma :

One would guess on a fuel injected bike that it will just misfire if there is an ignition fault. The injection system won't compensate for something it doesn't know about, so surely this points to the ECU getting bum signals? Either that or both injectors have worn to the point they are just pumping a tonne of fuel into the engine? That sounds implausible, and a duff ECU would just stop the bike working, which leads back to sensor inputs again *shrug*.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

trevor saxe-coburg-gotha · World Chat Champion Joined: 22 Nov 2012 Karma :

Wouldn't it run completely differently if it was using that much fuel? Wouldn't it bog, or stall a lot? My question is simply what are the other symptoms other than massively increased fuel consumption. I won't have any cures to suggest but I'm just genuinely curious.
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Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

Is it stupid to suggest a leak?
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trevor saxe-coburg-gotha · World Chat Champion Joined: 22 Nov 2012 Karma :

What I was thinking - but wouldn't it stink all the time? Maybe in hot weather it would evaporate a lot quicker and so not smell as much because it's not around long enough to.
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"Life is a sexually transmitted disease and the mortality rate is one hundred percent."

Mobylette Type 50 ---> Raleigh Grifter ---> Neval Minsk 125

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Islander · World Chat Champion Joined: 05 Aug 2012 Karma :

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

Should be able to smell 12mpg.

I vote fouled injector.
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Easy-X · Super Spammer Joined: 08 Mar 2019 Karma :

ECU codes? Heck, I'd take a look at the plugs first - need to ascertain whether excess fuel is going through the engine or leaking out the bike.
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Shaft · World Chat Champion Joined: 27 Dec 2010 Karma :

MarJay · But it's British! Joined: 15 Sep 2003 Karma :

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

No real running faults just a very lumpy power delivery. Idle had to burned from 1200-1600 but didn't seem fast
Stinks of petrol, soots the plugs and the end of the exhaust is black after 50 miles. It is VERY obvious it is running rich.

No faults reported on the OBD from the injectors but I had thought about those as well.

In regards to the throttle body area nothing is available separately except the injectors so the fast idle throttle servo and TPS cannot be replaced you need to buy the complete throttle body assembly at £862.

It could be an earthing problem between the ECU and the battery but this is unlikely as everything else is good but if it is this it will need a new loom or some serious messing around rewiring.

Checked the tank size which is 15.5 litres and its getting 50 miles per tank so 14.6mpg.

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Just checked the loom and it's all good.

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

have you got the old lambda sensor? The ECU doesn't normally identify a fault with those and if it goes open circuit it will assume too much oxygen and pump loads of fuel in to compensate.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Kawasaki Jimbo · World Chat Champion Joined: 09 Oct 2015 Karma :

I was wondering if the fast idle (thermo-wax) valve was sticking, and I recall you changed the coolant recently. Air lock? I’ve no idea if this is feasible though.

Easy-X · Super Spammer Joined: 08 Mar 2019 Karma :

I'd have thought the lambda sensor would only have a moderate effect: it only controls the closed-loop idling and cruising Thinking

Can you get any of the sensor output from the OBD2 tester? I have an app that links to my Bluetooth dongle and I can read out things like manifold pressure... maybe one of the other sensors the ECU uses is wonky and that's throwing out the fuel table.
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sickpup · Old Timer Joined: 21 Apr 2004 Karma :

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

MCN · Super Spammer Joined: 22 Jul 2015 Karma :

TLDR

Old British army trick.

Sit the beast on a sheet of 'clean' cardboard.
Engine cold and off for an hour.

Then engine running.

Look for wet patches of those stains that dried petrol leaves on stuff.

12MPG sounds like a leak.

If it's leaking onto something warm it will evaporate rather than drip.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

sickpup · Old Timer Joined: 21 Apr 2004 Karma :

trevor saxe-coburg-gotha · World Chat Champion Joined: 22 Nov 2012 Karma :

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

If the plugs on one cylinder is fouled, I would be looking at the injector for that cylinder. If it's both cylinders, then something is telling the injectors to squirt in too much fuel. Are both plugs fouled?