Cali Ev 2004 spitting back at around 2000rpm

Hi my Cali runs great, ticks over fine and accelerates fine except it won’t run cleanly at around 2000rpm and gives the odd spit-back.
This corresponds to around town speeds so its a bit of a nuisance.
By whacking open the throttle this can be avoided or changing up a gear to get away from the 2000rpm mark.
I’ve replaced all the obvious things i.e. air filter, fuel filter, plugs, crank position and temp sensors. Ran injector cleaner through system to no avail but am now at a loss as to what the problem is, anyone else experienced similar or can anyone make a suggestion. Many thanks.

My '01 Stone did similar and it was the TPS. The TPS gets dirty or scarred in one position so causes the issue at one throttle position. Mine occurred at the cruising speed position.
I replaced it with a Harley-Davidson TPS which was a tenth of the price of the Guzzi one.

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Hi Mackers, Thanks very much for your reply. I’ve read up about the TPS which is all pretty new to me never having dealt with petrol injection systems before the Cali. It seems like there is some what looks to me like complicated setting up to do, is that what you had do do when you fitted the new TPS?. I guess new TPS is now on my shopping list. Thanks again.

My problem occurred over a decade ago. With what I saved by NOT buying the Guzzi TPS, I bought the VDST software at the time and set the TPS with my laptop. Subsequently lost the VDST program in a computer crash! I’ve read about the back probing technique to set the TPS but never tried it. I’ve wondered if spraying contact cleaner into it might work?

Ta Mackers, can’t do any more about it just now but I’ll report outcome once I get back to it.

I have the same problem with both my Californias. The sidecar isn’t as bad, probably because the throttle tends to be slightly further open because of the extra load. The solo has a piggyback fuel adjuster which fools the ECU into thinking it’s a lower temperature. It helps but isn’t the answer. I’ve tried the probe technique as shown in the manual to check the TPS but get voltages nothing like that of the manual? So gave that up, obviously doing something wrong.

Thanks Maxrevs, I’m curious to know did you fit new TPS because I’m willing to buy one and hopefully adjust manually without what seems to me a quite complicated electrical testing procedure. I wonder if anyone has tried that.

I didn’t fit a new TPS. For two reasons; - I would have to take the sidecar off to get access to clean off the paint on the screws that hold the TPS and more importantly I couldn’t get the voltage reading to work as described in the workshop manual. I was getting 5V where it should be reading 536mV at a throttle opening of 3.6 deg. Hence I’m doing something wrong or something is way off.

OK Maxrevs, once I get back to it I’ll just get a TPS and chance adjusting by trial and error.
I’ll report back when that happens unless anyone else joins in conversation and tells me that is not possible.

I have read of a bloke setting the TPS manually by “ear tuning” but I don’t see how it’s possible. It is extremely touchy and the slightest nudge will send it it way out. Even as I tightened the screws, that was enough to ruin the adjustment so I had to keep resetting it.

Ok Mackers I guess that possibility is out the window then, thanks for the advice.

Thanks for posting this as I have been troubled by the same issue, especially at around town speeds. What I about to type may be nonsense (I am not mechanically oriented by nature as you will see) but here goes:

Spit-back is worse during times I am obliged to use low revs for long periods.
The long gearing does not help as very often 1st is too low and 2nd a bit high for modern traffic conditions.
Because of the above and in order to prevent the ‘spit-back’ I ride the clutch a bit more than other bikes in order to keep the revs out of the trouble zone.
It happens less with E5 than with E10, I am sure of it.
It happens less after a wee dod of RedX or similar.
All of the above could be nonsense but the avoidance of spit-back has become a whole new game when riding the Cali Special!

Hi GodBotherer, also thank you for taking an interest. I am pretty mechanical but know little about petrol injection and am on a steep learning curve. Yes our shared problem seems to be not uncommon judging by other people I’ve spoken too. You mention E5, I use it pretty much all the time and can’t tell any difference. What I failed to mention earlier is that it’s generally OK until it gets properly heated up, say after about 10/15 miles. As I said earlier this might be a long haul but I’ll post if anything significant happens.

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First time I’ve replied to a post so not sure how it all works but a fascinating topic which applies to my stone as well. Any chance you have the Harley TPS part number or advice on where you got it from. Ive seen similar looking things on eBay but it would be helpful to know the exact part. Mine has the slotted screw holes to allow manual adjustment.
Thanks in anticipation

HD TPS vs MG TPS Replacements

Hi Folks, an update on the spit-back problem. I have a Moto Guzzi friend who is much more knowledgeable than me put Guzzi Diag on my bike to test TPS, it came up as reading normal.
Anyway to cut story short prior to his testing I dismounted the ECU to get ID from rear of box and whilst doing so cleaned up all connections including it’s earthing wire. I also nipped up a bit further the throttle body rubbers (they were replaced some time ago) Also I put back in the Brisk LR17YPY plugs which I’d replaced some time ago with NGK BPREIX 6637 plugs. I of course never tested bike immediately after doing this - however all seems to be well and I’m not sure what the fix was. I’ll try putting NGK’s back and see if there is any return of the problem but for moment I prefer to leave well alone. Sorry folks this probably isn’t much help to any of you with your problems but it’s always good to get things out in the open. Can’t understand why problem only showed around the same rev range. Keep in touch.

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You all may want to have a look at this interesting link for resetting the TPS.

you could also visit
have a look under electrical, all 11.11.05