Help: Rough engine response

Anything to do with the 1200 GranPasso series
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rrey
Posts: 28
Joined: 17 Apr 2012 20:39
Location: SPAIN

Help: Rough engine response

Post by rrey »

Hi there!.

More sensations from the bike, now I´ve covered 200Km more on it:

The engine runs really bad when low on throttle and up to 4 Krpm. To be more accurate (I´ve fitted a datalogging system to find out), the engine runs well till 5-7% throttle and then badly from there up to 35-37% (which is a lot!) and up to 4000rpm. Actually you can drive at 3Krpm in that range of throttle and feel its lack of response when opening, very very lazy and jerky. You even feel that cruising at 120Km/h the engine feels very unconfortable and even a bit jerky as well even at constant gas. AFR is 12.7-12.9 in that range which is on the rich side but OK, definately not the reason for this problem.

When you remove the lambda sensor from the cat and leave it to the air, the engine runs the same!. No change!.

I´ve reset the throttle, changed spark plugs, even checked the air screws at the throttle bodies. On of the crews was closed (front cylinder) and 1 turn out for the rear one. I finally adjusted both to 1 turn out for %CO but anyway I tried 1/2, and even all the way to 2 turns without any improvement. Does anybody knows what the settings are from factory??

Once you are over 35% throttle the engine feels powerful and reponsive but till that point feels like rubbish. My previous Corsaro didn´t have this problem at all!.

Any suggestions??. I´m quite desperate because this is the cruising engine speed and I´m having a trip to Croatia in 3 weeks!!

Thanks guys!!
DaveH
Posts: 113
Joined: 22 Apr 2010 22:07

Re: Help: Rough engine response

Post by DaveH »

rrey wrote:Hi there!.

Does anybody knows what the settings are from factory??


Thanks guys!!
From the factory, the throttle bodies are synched for low speed only - both air screws are fully shut and then the scew that is pulling the highest vacuum at idle, (usually the rear) is opened until both bodies are pulling the same.

The manual stresses that one screw should ALWAYS be fully shut.

Seems bizarre, but the stepper takes care of air flow at idle speeds.

The high speed synch can't be adjusted without messing with the sealed linkage rod.

I wouldn't bother unless you know what you are doing. It's unlikely to drift anyway.

I reckon you need to put back to factory settings and look elsewhere for the problem.

It's likely the lamda is f**ked if it's not making any difference in free air - they seem a weak spot on these bikes (new NGK replacements are aailable for abot £70 ish) - I've disabled mine and the bike runs much better.

Have you checked for fuctuations in te TPS voltage readings ?
Dave H


Ducati Multistrada 1200S DVT :)
Moto Morini Corsaro 1200 :lol:
Beta RR300 :mrgreen:
rrey
Posts: 28
Joined: 17 Apr 2012 20:39
Location: SPAIN

Re: Help: Rough engine response

Post by rrey »

Hi Dave H!.

Thanks for your prompt reply.

We have checked synch and it is perfectly OK. It actually seems it is not dependant on this idle screws because it is not affected by this regulation. Interesting that factory recommends front completely shut and adjustment for the rear cylinder. I´ll back to the factory settings as an start point.

TPS has been adjusted and set , no voltage fluctuations with its signal and lambda, well.. diagnostics shows everything OK.

Do you have a ref# for a lambda replacement?.. Some say that one from DUCATI 848 makes it run better... is this OK?

Kind regards and THANKS!
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toggy
Posts: 282
Joined: 10 Apr 2009 17:06
Location: United Kingdom,Poole

Re: Help: Rough engine response

Post by toggy »

Any updates to your bike issues ?
Red S
Posts: 91
Joined: 18 Oct 2009 14:34
Location: Surrey

Re: Help: Rough engine response

Post by Red S »

I had a power commander fitted to mine (a 2009 model) in an effort to correct overheating (running too lean) and stalling a lot. And I do mean a lot. On one 20 mile journey it stalled about 15 times, which was pretty much every time I came to a junction. 3X were not able to resolve it. I ended up using HM racing in Edenbridge, who had difficulty changing the fuelling at low revs with the existing Lambda sensor. After a fair bit of research, they installed one from a Ducati 848.
This gave a 90-95% improvement. If I run 97 RON or better fuel, the stalling is almost completely gone. The fuel efficiency seems better, at about 42 MPG, or more on a motorway run, and it runs really nicely. I can get over 220 miles out of a tank with 2 or 3 litres left. I can't get more than 25 litres in mine though.

It also makes more than 118 bhp at the rear wheel now, according to the dyno. It wasn't cheap, but with a 200 mile round trip to 3x (several times), I got fed up with not getting any improvement.

The work was done over a year ago, and the stalling has got a little worse on lower grade fuel since then, but it's still a vast improvement on where I started. Hope that helps.

Oh, and the PC111 I have is the Corsaro model.
butchamphib
Posts: 103
Joined: 26 May 2010 12:57

Re: Help: Rough engine response

Post by butchamphib »

Did you fit the O2 optimiser with the power commander?
Red S
Posts: 91
Joined: 18 Oct 2009 14:34
Location: Surrey

Re: Help: Rough engine response

Post by Red S »

I had the PC fitted professionally. I don't know whether an O2 optimizer was also fitted. If it's not part of the standard fitting then it probably wasn't. Does this make much difference?
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