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GT 1000 cut out w strange symptoms

5K views 39 replies 11 participants last post by  Metman 
#1 ·
Hello fellow MS'ers.
I seek help with my GT 1000 which died 1/2 mile from home, it wasn't electrical, it just stopped running. So, got it home, yes I have spark at all 4 plugs. I also pulled cam belt covers just to check obvious, all looks as it should. Next I pulled the Corse Dynamics fuel pump assembly hoping it was a disconnected rubber line from the pump to the filter...alas, its on there as it should. Now on to the strange symptoms:
1. Low fuel light comes on at key turn then is out even w empty tank and assembly in my hands. Wires to the sender look okay and I disconnected it, reconnected it, so that little sender appears to be bad. It is related to the bike not getting fuel? IDK? Fuel pump whirrls so yes, that's getting power. I have yet to change filter, all internals looked very clean however and I wouldn't believe a fuel filter would just acutely shut off fuel to engine?
2. I'll hit the starter button and the starter motor will do its thing and still turn with my thumb away from the button! Yes it will stop spinning with kill switch. Can someone explain if that's a normal thing with no combustion?
Any help with narrowing down what I believe is a fuel issue is appreciated!
 
#2 ·
... I'll hit the starter button and the starter motor will do its thing and still turn with my thumb away from the button!
This part sounds like normal behavior for a Sport Classic starter. Turn on key, push starter button briefly, release it and the engine cranks until it starts. You don't need to hold it down until the engine fires.
You could disconnect the fuel line at the throttle body, stick it in a container and see if there is fuel being delivered when the key is turned on.
 
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#3 ·
Thank you for that info. I bought the GT 1 year ago, did a bunch of needed work, rode it a whopping 1 mile or so, down the street sort of thing. It's in beautiful condition now and so coincidental this list of things is occurring.
1. Starter spinning on its own: This isn't an issue, let's move along.
2. Low fuel light won't respond even with assembly in my hands and plugged into the connector. I'll jump it and report back.
3. Yes I'll disconnect the fuel lines at intake/injector and report back.

Lastly any advice on testing injectors?
 
#6 ·
Next I pulled the Corse Dynamics fuel pump assembly !

Do you have the Corse Dynamics fuel pump plate with the chrome plated metal quick disconnect fittings? I have them on my bike and ran into a problem with the quick disconnects. The small shutoff valve inside the quick disconnect is cheap plastic and failed and wasn't allowing fuel past the fittings. I found if I pushed in against the fitting it would let enough fuel past to run but as soon as I let go it would shut off and starve the engine. When you have the lines off at the injector, if you don't get good flow push in on those quick disconnect fittings and see if the flow improves.
 

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#8 ·
VF, Thanks for taking the time to reply. I'm glad you mentioned this because when I had the assembly (yes, same as pictured, same as yours) sitting on a rag on the bench, I saw that little off white plastic piece surrounded by a spring. I thought oh, just press it back into the fitting but I saw the O-ring inside the fitting. I couldn't get it back in so rather than force, I took both in and out fittings off the plate and saw how the little plastic piece was held by the O-ring. So, back in business on that. Maybe it will be worth putting everything back together and just add gas rather than continuing the chase? That would be pretty nice and thanks again for taking the time to comment.
 
#10 ·
Hmmm, not saying that's your problem, but I'd get the old gas out of there and put fresh in. If it was really old (and bad gas to begin with), could have some varnishing type problems causing issues with the fuel injectors, etc.

I'm not sure best place to drain it from (some others here may be able to help with a suggestion), but I'd definitely get some fresh petrol in there. At least eliminate that variable.
 
#15 ·
Belter I just sprayed cleaner into intakes and yes it runs. Texting w a non moto buddy, he too suggested while the tank is apart and has simply a splash of old gas, pour it out and go fetch a can of non ethanol. Remote chance of success but I’ll report back in a couple of hours. Thanks for your involvement.
 
#16 ·
I wonder if adding one of the fuel treatment additives might help with cleaning out the tank? So do everything you just said above, but also add in some fuel injection system treatment with the fresh gas ... I dunno, maybe one of the Lucas products? That might help to clean out the entire system including the injectors, regulator, pump, etc..
 
#19 ·
Sounds good. I just got back from running it around backroads, it’s not smooth but becoming a little better. I suppose the more fuel I can have flow through, that is a plus. Again I thank each of you for the support and will check in w an update.
 
#20 ·
A little update:
The GT is running but it's not completely happy. It still feels like it is starved proper fueling and it pops like crazy. Since posting last, I've dumped in around 1.5-2 ounces of Lucas injector cleaner and added a small splash of 91 non ethanol. It's a little difficult to start, and if I give it a rev, as it comes back to idle, it will stall. FYI, I never did disconnect lines to injectors. At this point I'm thinking I may need to in order to eliminate the possibility of a gelatinous obstruction? Or perhaps just be patient and keep running it to keep fuel flowing? Any other angles of approach, I'd appreciate it.
 
#21 ·
You know, ignoring the "old gas" issue, just reading your most recent comments I would question whether you might have a vacuum leak. The "starved proper fueling and it pops like crazy." sure sounds like the mixture is way lean, much more often a vacuum leak than a plugged fuel line.

If you've never chased down one, use some WD-40 with the extension tube to pinpoint spray potential leak areas while the bike is running. If there's a leak the rpms should increase. Also, use a bright flashlight when inspecting hoses for cracks. Speaking from experience, it's really satisying to find your "problem" is just a cracked hose. And if the emissions canister has been removed, make sure there's no open little connector tubes that should have caps. You may get lucky and solve all your problems with a little plastic cap from the auto parts store.

Just a thought.
 
#23 ·
Well Mr. Jeff, you were right to look for a vacuum defect. There was one, vert cyl, the little rubber cap from canister removal done by p.o. It was split and I simply sliced off the bottom portion of split and thought that Jeff fella in Portland is damn clever. Alas, it is still hard to start but seems to idle easier.
As you all help me diagnosing this, with anything around half throttle, power is not really there. Rolling along 1-2nd gear, it’s not so much a surge but the pop is there and the presences of intake fart sounds certainly seem symptomatic. Thank you all for the help!
 
#24 · (Edited)
Hallo RK :smile2:

I have had problems ala you describe.

Please see this thread:

https://www.ducati.ms/forums/77-sport-classic/722109-white-i-wait.html

and

https://www.ducati.ms/forums/77-sport-classic/716997-fuel-circuit-injectors-cloged-not.html



After beeing strandet for the second time I did a very thorough search for the reason the bike just died on me some times.

After searching the fuel system I did found out that the CPC Quick Release Metal Fuel Connector in the out port of the fuel flange was bad. Whether it was bad assembled or it did not have Viton O-rings I do not know. Either way the connector will restrict the fuel flow in some cases. The flow restriction is caused by swelling of the internal O-rings or if the O-ring not are seatet proberly. The inadequate or restricted fuel flow can cause engine stalling at throttle opening.

I did contact Motowheels but it seemed to be a loooong proces doing so, so I purchaced a new CPC Viton Connector at AFT Systems in Germany.

Now I have been riding my Paul Smart trouble free since I mounted the new connector (1600km / 1000miles).


I am not the only one who have had troubles with the CPC Connectors. This thread
https://www.ducati.ms/forums/77-sport-classic/616337-fun-new-fueling-issue-2.html did confirm I was on the right track.

All the best

Ciaooooooo


Moller
 
#25 ·
Thanks Moller. They look proper but i will certainly heed your advice and keep an eye on those connectors.
Meanwhile I did remove injectors and there was just a bit of varnish around the edges. On the front cylinder, there was a fair amount of varnish where the injector fits and with carb cleaner and q-tips, I cleaned best i could, pretty spotless. Is it normal to see a a fair amount of varnishing in the intakes and the backside of the throttle butterflies? Will a product like the Lucas eventually cleanthat up? I have to say, still hard to start but I think getting a little better.
 
#26 · (Edited)
Quick update is I decided to clean those intakes best I could w spray and removing the intake rubber boots and getting the injectors out of the way for the process. There certainly was a bunch of varnish yuck and question on the little ports, one ahead of the butterfly and 2 below. The 2 behind the butterfly appear to be emissions related, yes? The one in front of butterfly is idle? I didn't touch them but they were dirty, no doubt. Bike idles happier but now I'm hesitant to ride it with the popping still present. I don't want to do any damage. Still stumped by this...
Thanks for the additional thoughts and direction.
 
#27 ·
Popping on deceleration is frequently a sign that you've got an air leak in the exhaust system. Maybe check the header pipes to verify they are secure to the heads, and look for any gaps at the joints between components?

Sounds like your getting it sorted out, let us know.
 
#30 ·
Well, any shredded gasket can't be good. By regulator, I'm assuming you mean the fuel pump mounting plate and it's large O-ring? Definitely fix that.

Exhaust leaks can allow your system to draw in outside air. Lean conditions encourage backfire, which is the Popping you're referring to. As delivered stock, my GT was very lean and would surge at steady throttle and buck & pop some on deceleration. That was on a new bike. I was able to cure the fueling woes pretty well with a fatduc unit, then went to a DP ECU later. Yours has been messed with by multiple people, all I can say is be methodical and eliminate the possible sources, which it seems that you are doing.

duc96cr has a good suggestion as well, you could well have an unfortunate combination of non-optimal mapping with contributing mechanical factors. Keep plugging away at it!
 
#29 ·
Sounds like it’s fuel starvation so yes, fix that. Also, make sure fuel lines are not kinking or collapsing when tank is in place. Use actual reinforced rubber line, not the clear plastic stuff.
 
#31 ·
As you all assist with your detective diagnostic skills, how’s this? It was cool yesterday, 50’s, and I hopped up, rolled away gently on our narrow and quiet backroads. The bike could not have been better. Proper power, no or minimal decel backfire, idled well. I feel the only variable besides more Lucas cleaner infused fuel flowing through the system was the weather. Let’s say it was a 20 minute ride.
After parking for say 15 minutes, the symptoms were back to being consistent w the above discussion. So the bike was super happy in motion at sunny mid 50’s morning...well who wouldn’t be? Does that condition prompt any further thought? Thanks for your input.
 
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