749s Warm Start Problem?

**murf62** · 04 Aug 08, 04:52 PM

I've got a 04 749s and it's been difficult to start when the engine is warm for some time. When it's cooled down, usually it starts no problem. When it's playing up, the exhaust smells of petrol, so I am assuming that maybe it is flooding because the mixture is too rich at idle?

In the last week or so, it has got worse and I tried to start it today, when the engine was cool (ambient air still 38c though), and it wouldn't start. After a couple of attempts the EOBD light came on and indicated a fault code of 34.0, which according to the manual is "SIGNAL PANEL (SENSOR DISC.)" I can find no other reference to this sensor disc in the manual. Could it be this that is causing my problems?

So far, I have changed:

Spark Plugs
Air Filters
Fuel Filter
Coils
Oil & Filter
& I've tried different octane fuels

Any ideas?

**barry** · 04 Aug 08, 08:27 PM

Could the coolant temperature sensor be playing up?
Don't know the 749 intimately, but have been a car mechanic for donkeys years...
...just a thought..

**stevel** · 04 Aug 08, 08:49 PM

I'd agree with that, it senses when the engine is cool and richens the mixture.....maybe some connection there (or maybe not a good connection......)

**murf62** · 05 Aug 08, 04:30 AM

The output from the coolant sensor sends a signal to the dash and the engine temp there reads correctly, so it can't be the sensor. Obviously the sensor also sends it's signal to the ECU, so it could be a problem with the ECU, or maybe a even weeping injector perhaps?

I would like to know what the "Sensor Disc" mentioned in the fault code is all about though.

I forgot to add before that I have also fitted a new battery, and the charging is fine.

**BaggaZee** · 10 Aug 08, 08:10 PM

Hmmm, isn't the 'sensor disc' the immobiliser coil?
The relation to temperature doesn't seem right but the description does. I love the translation in the workshop manual!

**murf62** · 11 Aug 08, 06:22 AM

Well the dealer over here has been messing with it for a few days now and swears blind it's the injectors. Makes sense to me as overfuelling could cause the difficult hot start and the exhaust certainly smells of petrol when it won't start.

The dealer wanted €1050 for new injectors over here, but I've got a second hand pair in a complete airbox off Ebay for £80. I hope they fix it!

**BaggaZee** · 11 Aug 08, 12:26 PM

Do have a look at the immobiliser though, it's been known to cause problems and is a very easy fix if it is the culprit.

**murf62** · 14 Aug 08, 06:16 PM

It can't be the immobiliser because it is trying to fire, it's just far too rich. Would it turn over if the immobiliser was playing up?

**BaggaZee** · 14 Aug 08, 09:43 PM

Ah, I didn't pick up on the fact that it's turning over, sorry. I still think that's what the 'sensor disc' is though.

**murf62** · 15 Aug 08, 05:56 AM

Yeah, maybe it is? I have the full Ducati manual and there's no mention of it though. I am hoping that the error I got was due to my constant cranking and failed attempts at trying to start it, turning key off/on etc.

I am sticking my neck out and hoping the injectors fix it, otherwise I'm a bit stuck!

**murf62** · 29 Aug 08, 06:18 PM

The dealer rang me today (bike not drug) and said my bike is now running & starting 100%, after fitting the injectors I gave them. I'm picking it up in the morning, so will see how it goes. They are billing me for 4hrs labour (€160), even though the "technician" has spent over 20hrs messing with it as he feels he should have nailed it in less time. This problem has been getting steadily worse for the past 6 months, so I really hope it's sorted. If it's fixed, then it is certainly something to bear in mind for other people with starting problems, especially when hot.

**Ghost** · 29 Aug 08, 06:30 PM

How coincidental is this post.

Yesterday morn mine was a bitch to start but as soon as I keyed on the EOBD lamp was on. It did start and was still on. I rode about 3 miles to get fuel come back to bike keyed on all lights went out, got to work 12 miles away.

Lunchtime went to go out, EOBD lamp on and would not start at all and smellin of fuel, but I think this is just cos the pump keeps priming at each key on.

EOBD code 34 Signal Panel sensor WTF is that. I think it is the barometric sensor that is built into the display unit. On the back of the unit is a breathable bung.

I had battery off battery box off checked the relay and connectors put some jump leads to the terminals and it fired up. Put it back together and rode home. Just this minute started it to go put it in the garage and the EOBD lamp is on again, prob tomoz it will be off.

**murf62** · 30 Aug 08, 05:00 AM

I've had error 34 too. I never did find out what it was, the shop manual says "Signal Panel (Sensor Disc)", but there is no other mention of it apart from that. I concluded that it was just caused by the battery getting low and me cranking it over & over, I don't think it's related to the root of my problem, as I only had it come up once in all my months of trouble. I would certainly be interested to know what error 34 actually means though.

**murf62** · 30 Aug 08, 05:09 AM

Here's my other thread about it:

749s Warm Start Problem? - Ducati.ms - The Ultimate Ducati Forum

**murf62** · 30 Aug 08, 03:09 PM

The outcome of this, for the sake of completion is that I now have the bike back and it's a different bike! Starts in a couple of seconds every time, hot or cold and runs really sweet.

Anyone with problems similar to mine should bear in mind that it might be the injectors because I tried everything else first!