Dead Aprilia Shiver - any advice please?

[c_dug]

My Shiver 750 left me stranded 15 miles from home at the side of the road last Thursday and I'm getting a bit nervous that I'm going to end up throwing four figures at a mystery error and might not have a working bike at the end of it.

Just wanted to run through the situation with you all for any thoughts or opinions you might have.

I was about 15 miles into my commute to work and riding along at about 45mph when in an instant a red check engine light started flashing, the words "URGENT SERVICE" appeared on the dash, and it went into limp mode. When I pulled over the revs were jumping about near tickover, and when I turned it off it wouldn't fire back up again.

I took a video about 3 hours into my near-6 hour wait for the AA to show up: https://youtu.be/pw8yOZ-zu1o

I looked through the on board diagnostics but it didn't show any error codes. A Google search at the side of the road said that if the on board PC showed no errors it would need to be plugged into a computer for more info.

The AA man said he knew a good bike shop around the corner from where I'd broken down - I've never put a bike into a shop for work before so wasn't too confident but the AA guy said if I didn't like the look of the shop when we got there he'd take my bike home for me anyway, so I gave it a shot.

The bike shop is run by an ex-Ducati mechanic who has set up his own shop (he worked for Hyside and knew enough about the dealership for me to believe him), he mostly sells Lexmoto from his shop but there were a few big bikes in there for servicing including a Ducati Hypermotard and a BMW, anyway he seemed trustworthy and I liked the cut of his jib, and besides I don't have any free time until Christmas, so I left it with him to have a look at.

On Friday they plugged the bike into their OBD reader it showed a front cylinder air intake fault. They replaced the MAP sensor, some vacuum lines, and cleaned up some connectors, then took it for a test and it worked fine.

When I showed up on the Saturday to collect the bike, I put the key in the ignition the red light was back on and revs bounced up and down like in the video above.

Great.

The guy at the shop seemed genuinely caught off guard by this.

Now when plugged in to their laptop it shows "unknown error".

I left it with them this week and he says that if you flick the ignition on and off a few times about every third or fourth time it comes on with no error light, and then if you ride it it works absolutely perfectly.

He's since spoken to a friend at an Aprilia main dealer for some advice. The Aprilia tech has suggested it probably needs a new throttle body, at a cost of £600 and about six weeks wait from Aprilia, and possibly a new throttle position sensor too.

Nobody can make any promises that this will actually fix the issue and the cost of parts is going to start building up quickly. The advice of the bike shop is to take it as it is rather than throw parts at it hoping it fixes it. I'm not too chuffed at the thought of having a mostly broken bike as a commuter.

I do have access to an identical bike so I can do a bit of part switching and swapping myself over the Christmas period, but I have very little experience with anything with a proper on board computer and electronics so I don't know how much of an option this actually is - presumable I need an OBD plug and some software too?

Having typed all this out I actually feel a bit clearer about what I should do, but I really would appreciate any advice you might have.

Thanks!
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Easy-X]

Entirely new throttle bodies with all the associated sensors and injectors? Well yes, maybe that would fix it...

Thing is a throttle body in mechanical terms is very simple, more of structure to hold components. Strip all the bits off and there's not much left you can't visual inspect, unlike a carb that has all sorts of hidden passages. Granted it doesn't look that simple in-situ wrapped in plastic covers with all sorts of wires and pipes going in

If you have a bike with the same throttle-body assembly then swapping the whole lot over as a unit sounds like a good plan and if it does fix things you know what needs stripping down and testing. Do you have a multimeter?
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[A100man]

6 hour wait - FFS what was their excuse?


You'd like t think that better diags would be available form a dealer..

Perhaps take it back from teh local guys as is and pay for a diagnostics test only if that's possible at Aprilia dealer- then figure out how best to replace the broken bits. Like Easy says it could be just one sensor on the body such as a TPS..

I get the impression dealer mechs swap bigger clusters of parts for speed of completion whereas DIYers can be more cunning..
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[MarJay]

I'd call Griff at AP workshops. If you're nice to him it's possible you could pick his brains without taking the bike to him. If he doesn't know what the problem is then you probably need to pray to the gods of Italian Electrics...

https://www.apworkshops.co.uk/service/
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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.

[Pete.]

Can't imagine why you'd need to swap the entire throttle body unless the shaft bushes were wron so much that the TPS was giving insensible signals.

The first thing I would do is mark the orientation of the TPS then remove it from the throttle body. If the fault goes away the TPS is probably knackered.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[WD Forte]

[Robby]

I would be looking for a bad connection, or a wire broken inside its insultation where it bends around the headstock.

[A100man]

[c_dug]

The bike is home so that's a start.

The mechanic at the shop took me through the wiring diagram and ECU fault log and I can understand now why they changed the MAP sensor initially, and changing the sensor seems to have made it work better which is something.

The fault now is definitely an odd one. When the bike is cold and the ignition is first turned on, the red light flashes and the dashboard displays "URGENT SERVICE". If fired up like this it does exactly as the video in my original post showed with the revs bouncing about at 3krpm and the throttle doesn't work.

However if the ignition is then flicked off and then on again the fault clears and the bike works perfectly, I rode 15 miles home without issue.

When I got home I turned it off and on a few times and the error didn't show a single time so as the shop said it only seems to be an issue when cold.

Definitely an odd one.

The shop went over the loom in detail, particularly around the headstock area. They also removed and cleaned the ECU plugs.

The ECU fault still shows "unknown error" which is particularly unhelpful!

The saga continues!
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[c_dug]

[c_dug]

S663 and S664 are MAP sensors, the green wire attached to ECU pin 15 is a shared wire between the MAP sensors and TPS and is where he suspected an issue but it all looked fine.

https://www.bikechatforums.com/files/img_20211212_095128.jpg
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Pete.]

Shitty arrangement. Each sensor should have it's own return to avoid ground offset errors. I learned about this when building my turbo bike.

https://patents.google.com/patent/US9589394B2/en

An ECU onboard a vehicle may suffer from a ground offset condition. A ground offset means that an expected reference voltage (e.g., zero volts) of an ECU has shifted. Thus, if the same signal voltage is measured relative to different reference voltages, then different measured values will be obtained. In an ideal network of ECUs, all of the reference voltages are identical such that all signal voltage measurements are consistent relative to one another. Ground offsets in vehicle ECUs can result in inconsistent vehicle operation, due to changing electrical loading. Moreover, ground offsets tend to worsen over time (perhaps rendering the stricken ECU inoperable).
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[c_dug]

Presumably if there is a grounding error I should be able to measure that with a meter?

Like showing either greater than 0 resistance to ground or voltage sitting above 0v?
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Robby]

You should. You could find the problem quicker by locating all of the ground points and seeing if any of them have any corrosion.

In the way the "unknown fault" error is helpful. If a single sensor or actuator was was returning bad readings, you would know what part is the problem - and the part is likely expensive.
If the problem is unknown, it's the ECU telling you there's too much noise to work out what is going on on multiple circuits.

Way out on a limb here, but when you first turn the key the ECU is going to do a number of high-current things, such as priming the fuel pump. If you immediately turn it off and turn it on again, the fuel pump (and likely other things) will not need anything like as much current - the pressure is still there.

If the high-current thing(s) are sharing an earth point with a signal wire(s), then that could explain it. High current, high resistance through a corroded connector, confused return to ECU.

Either way, first diagnostic step for me is to locate and clean up all the earth points, with a smear of grease to slow down corrosion. If the problem is still there, that's when I would begin the painful process of trying to locate an internal break in a wire. Wiggling the bars around helps to isolate the location of an internal break.

[c_dug]

I had the flashing reoccur once on Monday morning, but I've been in work all week and not seen it since. So strangely, for now at least, the problem seems to have solved itself.

Typically just as my OBD to USB cables arrive in the post

I don't doubt there is still an issue festering away somewhere so I'll go over the earth points anyway over the Christmas period.
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[defblade]

Been a long time since I was on Aprilia Forums with my Shiver, but they still seem to be active, so could be worth a trawl/post on there:
https://www.apriliaforum.com/forums/forumdisplay.php?63-2008-2016-Shiver-750-Dorsoduro-750

I knew there is a common sensor failure on these - a bit of re-reading on the forum says cylinder air pressure sensors - regular known fail point... but doesn't sound like your issue, sorry!
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Honda Varadero 125cc => Suzuki Bandit 650 33bhp => 77bhp =>
BMW K1200R Sport 163bhp => Aprilia Shiver GT 750 95bhp