Posted elsewhere but no response to date: New owner question. On a Track Day yesterday on my 2004 749S. I have just had a full Tuneboy related dyno tune and 114 rwhp. Previous mid range glitch resolved and it will take full throttle from 4000 rpm to rev limiter. The engine management light is now on until 2000+ rpm. Braking hard into hairpin corners and getting back on throttle and I am experiencing some serious delay in throttle response and then stuttering making the bike fall in on just off full lean and closed throttle. Pick it up and get up to 3-4000 rpm and it takes off again. Low speed throttle off being closed under braking and then banked over just doesn't seem connected. Some hesitation off idle when stationary also and a couple of engine stalls. Bike has 37000+ kms on it. I know the TPS is meant to be fragile but is there a lean angle sensor also? All ideas and advice very welcome as I love everything else about this bike!
Nothing on dash but I guess I have to find a separate screen? Sorry I am an old school bevel Duke owner/ex racer and the 749 electronickery stuff is a steep learning curve. Should have also mentioned that a later style ecu had to be installed to tune the bike on the dyno.
A bit of digging and learning! 2 Error Codes show, 1.2 TPS short circuit to earth plus 37.3 Immobiliser cable disconnected which I expected as the later ECU came from Tuneboy with Immobiliser deleted.
which ecu where or what was it from?? I know the tps on a 1098 for example works the counter direction to a tps from 749 .. they are wired differently 100% in 0 and 0 is 100% might not be relevant but fyi
These are the voltages I found on my 1198 TPS. As said above. High V = closed, low V= throttle wide open. TPS closed 4.71v and TWO 0.86v As said previously, the 749 TPS is on the front throttle body (the 848/1098/1198 is on the rear). You should see Low V = closed. High = TWO. The closed voltage should not be 0v and TWO should not be 5v. Did they reset the TPS after the reflash work?
ECU is said to be from an 848 (5AM?) but as used on later 749/999s. Nothing stripped down yet. ECU sold to me by Tuneboy and flashed with DP map plus immobiliser deleted so should know what they are doing for my bike. Tuner could then tune open loop tune throughout the range with improved power and mid range. Couldn't access the original DP ECU fitted to tune it and my "spare" was fried! No TPS reset was done and I now guess this is first action to take?
No open or closed loop on the 749 as they don’t have lambdas. Start with a TPS reset. If you don’t have diagnostic kit, buy the leads from LonElec and use JPDiag or Guzzidiag on PC or Scan5mx on Android (they are free).
Check the connection to TPS for the Tune boy. No experience with them, but power commanders can cause this when the connection to TPS signal wire goes bad.
Thanks Chris, I will be on that Monday morning. Not comfortable doing it myself and it will take longer to access the stuff required than taking it to our one only Ducati dealer in this State.
Thanks Nelly, Tuneboy is a Oz DIY software interface to the ECU not like a Power Commander where you have a separate unit I believe. I can't see whether the Tuneboy can be used to reset the TPS but will know more next week hopefully. My tuner bought the software with an access key to remap the DP map supplied on the replacement based on his dyno work with each cylinder being tuned separately for AFR and ignition timing. The dyno output look great but I think the TPS must be out of whack and being triggered at the wrong throttle opening.....I hope!?
Fingers crossed it is something simple. If the TPS has failed don’t be fooled by anyone saying you have to replace the whole throttle bodies. The TPS unit is used in Fiat Puntos in Europe and is a dealer available service part (part number 71738921). They cost around £33 from Fiat and are genuine Magneti Marelli. California Cycle works supply a pattern version.
Update. TPS was confirmed as reset before tuning work. Got the TPS checked out today using a local Aprilia/Guzzi guy and his software. First check showed throttle closed at 2.3 degrees which is the 999 value so reset to 1.3 for 749. ECU may have been a 999/848 5AM unit and reflashed with a 749 DP map before the tuning work so the 2.3 may have come from there? As the unit got hotter powered up, closed throttle dropped to 1.0 and then I slowly turned throttle up to 1/8th and then ¼ turn and it showed readings all over the place from 1.0 to 43.6 degrees. It would jump from 1.0-1.3 to 8 degrees with the slightest of movement just taking up the cable slack. Cannot be described as linear. I guess a new TPS is in order!? Now to find one.
Just to close this topic off, CWS TPS (ex Exact UK) arrived on Christmas Eve and fitted yesterday thanks to local guy for Guzzi software plug in and reset. I now have a linear TPS working and the rebuild begins. Fortunately a previous owner had modified the hidden front air box bolt and after removing all the other screws and disconnecting the throttle cables, the air box lid came off and the TPS could be switched after a bit of effort to remove the old one without disturbing the air box base, breathers, connector and cables. Thanks for the info detailed above and other threads that I accessed here and Stu at Exact. I have now found play in the rear ride height adjuster rod and I am in need of a replacement or new eyes if I can get it apart plus a bit of play in the swinging arm bearings although the through bolt was loose. Tightening it has improved things a bit (!) but I will now torque that up to factory values, sort the ride height rod out and see how we go. Cheers.
