Lumpy and dying tickover on S4

[LVC]

Hi guys - took the S4 for a run last night and the tickover has become lumpy i.e. fluctuates a few 100 revs above and below the 1k mark when on tickover in neutral or clutch in. Sometimes it keeps going, sometimes it just cuts and dies. Seems to run fine above 1500rpm and I didn't find any problems at higher speeds :scratch:

The only thing I've changed since the last run (about a week ago and was fine) is a Oil thermometer (screws in place instead of the standard plastic oil filler cap) but I can't see how that makes any difference at all. I guess filter and plugs is a good place to start but if anyone has any other suggestions I'd be grateful :hail:

Bike is a 2001 S4 with K&N (open air box), Termis and I believe an ECU chip change (all done over 5 years ago by the previous owner) and has always run fine up to now - clocked over to 12k miles last night - maybe an omen :thumbsdown: :on:

Thanks :yoparty:

[Albie]

Hi guys - took the S4 for a run last night and the tickover has become lumpy i.e. fluctuates a few 100 revs above and below the 1k mark when on tickover in neutral or clutch in. Sometimes it keeps going, sometimes it just cuts and dies. Seems to run fine above 1500rpm and I didn't find any problems at higher speeds :scratch:

The only thing I've changed since the last run (about a week ago and was fine) is a Oil thermometer (screws in place instead of the standard plastic oil filler cap) but I can't see how that makes any difference at all. I guess filter and plugs is a good place to start but if anyone has any other suggestions I'd be grateful :hail:

Bike is a 2001 S4 with K&N (open air box), Termis and I believe an ECU chip change (all done over 5 years ago by the previous owner) and has always run fine up to now - clocked over to 12k miles last night - maybe an omen :thumbsdown: :on:

Thanks :yoparty:

Well mine clocked up to 13001 last run so maybe not an omen. Im no expert but I read a lot about the timing sensor.Maybe its shifted a smidge

[LVC]

Thanks Albie - any idea where the sensor is so I can go have a fiddle ? :spin:

P.S. Congrats on the new baby - looking forward to seeing the photos :yoparty:

[jerry]

Its 99% probably the TPS needs resetting and the injectors rebalanced ..its so common that it ought to be a sticky.

[LVC]

Its 99% probably the TPS needs resetting and the injectors rebalanced ..its so common that it ought to be a sticky.

Thanks Jerry - that sounds complicated/expensive?? Is it a DIY jobbie or dealer/tuner :scratch:

[Nickj]

The TPS is just adjusting its position until it gets to the right resistance value then locking it down. They can be a bit twitchy to adjust, the value can hop about a bit if it's very loose, loosen it so it just moves.
Balancing the injectors, not a clue!!

[LVC]

The TPS is just adjusting its position until it gets to the right resistance value then locking it down. They can be a bit twitchy to adjust, the value can hop about a bit if it's very loose, loosen it so it just moves.
Balancing the injectors, not a clue!!

Great thanks - but what is a TPS, what do I loosen and where is it :banghead: :toilet:

[Capo]

Check out what Brad Black has to say, you may want to take it to a dealer.
http://www.bikeboy.org/ducati4vthrottleb.html

[LVC]

Thanks Capo - dealer it is then :spin:

Still don't get why it should be any different from the last run - gremlins in the garage maybe :scratch:

[jerry]

I have written out instruction on how to reset TPS before on this site surely the thread is in the archive?

Briefly ..../You do need to remove airbox lid and filter and then using a digital mutimeter on pins 1 and 3 of TPS rheostat with the throttle stop screw backed of completely ,you need to see 150mv on the meter as the base [position with the injector butterflies completely snapped shut.Its very fiddly to get right an one needs patience as the slightest movement can move the voltage massivly.

The throttle stop has to be set again after for good tickover and to balance you need vacuum gages or carbsticks .

[Albie]

I would say a dealer/mechanic then. Have you changed your fuel type garage or check your plugs and plug coils for breakdown. Horizontal ones get all the road cr4p.

[LVC]

Took the plugs and coils out this pm - the lower/horizontal one was nice and wet with plenty of brown water around the head of the plug :thumbsdown:

Dried it out and wiped the plug clean (the sparky end looked OK to me) and then sprayed plenty of WD40 around the place - fired her up and all seems good - will try again tomorrow and update this post. :on:

I'm hoping it was just the result of a 4 hour return trip from Mont St. Michel in some very wet rain a couple of weeks back that never dried out whilst she sat in the garage until Friday's little blast - really could do without an expensive garage bill and definately don't want to miss the summer fun :D

Fingers crossed tonight :spin:

Thanks to all for the advice - most appreciated :hail: :yoparty:

[Albie]

Should it be the stick coil god forbid like my lower on was badly corroded but still working I purchased 2 brand new ones. They are around £120 each:thumbsdown::thumbsdown: but I have one spare and the old corroded one. If you need one I will sell for £50 if you need it.

[LVC]

Thanks for the offer Albie - will run the bike tomorrow and get back to you asap - I think it might be worth me buying it off you anyway so I've got a spare for when it does stop working :mand:

[Bodybag]

I would suggest that its the coils and not the TPS. I had this on my S4. As Albie said, they're not cheap but they're still cheaper than a trip to a garage for a diagnosis. As they pick up all the crap from the front wheel, they tend to corrode fairly quickly. Mine had split open like a sausage on a frying pan by the time I checked the front coil. Does one of your cylinders cut out? If so, easiest way to check if it is the coils is to swap them over and see if the vertical cylinder starts cutting out instead.

Hope this helps?!

BB

[wheelybin]

My S4 had this problem, turned out to be the fron stick coil, I got one from a CBR 600 off ebay for a song. It turned out to be about 1/2 inch too long so I put it on the rear pot under the tank (out of sight). Bike now runs like a dream and has done for about 2000 miles since I changed it.

I had tried everything to dry out the old one, even a week touring Spain in pretty hot weather - made no difference.

All I need to do now is make some sort of water shield to fit over the front coil.

good luck

[LVC]

Dried out the front coil and (touch wood) all been fine since - I've got Albie's old/new one in case the problem comes back :D


Thanks for the advice :thumbsup:

[Bodybag]

Good to hear. As wheelybin said, it might be worth making a shield of some sort so that water isn't sprayed directly into the coil from the front wheel.