S4 Fuel Pump Wiring Issues, Revisited

[corndog67]

Ok, I bought an S4 a month or so ago.  It ate the fuel pump wiring under the tank because of a serious rubbing going on between the cylinder head and the bung/wiring chinga coming out of the tank.  SB Ducati replaced the bung/wiring thing, all was well.   Yesterday, there was a hiccup a couple of times under acceleration, felt like an ignition or fuel issue, just cutting out for 1/2 a sec, then coming back on, so I pull the tank up, and lo and behold, the wiring is getting mashed up again, and same same.   I called the Duc shop, they are working on getting me another, but in another post, it was recommended that I re-route the wires.  The problem is, looking under there, when the tank is lowered, the bung sits directly on/over the cylinder head.  No matter which way I route the wiring, it's still smashed against the head.   My idea is to put a 3/16 or 1/4 in. spacer under the pivot for the tank, raising the back of the tank a like amount, effectively giving another 3/16 or 1/4 clearance to the wires.  Does anyone see any problems with doing this?  It's still going to sit on the rubber spacers up at the front, the seat is flexible enough to still fit well, and hopefully this might fix it for good.  As it is, I don't trust this bike enough to ride more than 50 miles from home.   I would like to be able to putt for days with it. 

Thanks, Robert

[corndog67]

Also, if by chance my dealer fails to find a good wiring bung thing, which I believe that the parts fiche calls a fuel level sensor, correct me if I'm wrong please, which models will interchange, since there are very few S4's out there.   Any one have a used one?  They are kind of pricey new. 

Thanks Again, Robert

[needtorque]

My only suggestion for you continual problem is this.  Extend the length of the wire-harness using some new color matched wires and sodder the connections and wrap in shrink-wrap.  Ask the dealer to this or do it yourself.  With a repeated problem of this nature it is what I would do.

[corndog67]

But Torque, I feel the problem is not the length of the wires, but how low the tank is sitting, i.e., the wires are getting smashed against the cylinder head, directly beneath the bung coming out of the tank.  Even if the wires were longer, they would still get smashed right where they bend coming out of the connector.  Thanks for the reply though. 

[needtorque]

Ahh I get what you are saying now.  I think lifting the tank slightly as you suggested is a good idea.  However, the issue you are having and the speed with which the new harness went bad leads me to believe something else is amiss. 

Either the part that they are putting in there is from the wrong year or something in that frame is tweaked.  Otherwise an s4 straight from the factory would be having the same issues.

[Howie]

The dealer is missing something since this is not happening to all S4s.  Find a similar bike and compare.

[corndog67]

Ok, I made a 1/4 in. spacer and put it under the rear hinge.  The wires still touch the head, but they are not crammed down on it like they were.    I either going to splice into the wiring that is damaged and solder in some new pieces or get another fuel pump wiring setup.   It if is still going to cook the wires, while I was at it, I made a 3/8 spacer too. 

Does anyone know if the S4 wiring setup for the fuel pump is the same as  on any other models, the book lists it at $175, and I'd rather not pay that on a bike that I have put less than 500 miles on since I bought it.  There seems to be quite a few gas tanks for sale on Ebay and other places. 

[ducpainter]

I wonder if the tank is the right one. Perhaps the PO replaced it and got something wrong.

This is certainly not a normal circumstance.

[Speeddog]

I think ducpainter is onto a possible cause.

A quick scan of parts catalogues shows at least 3 different part numbers for the fuel level sender.

59210101A is the original S4 sender, part# has been superseded with 59210151A.
59210152A is an '05 S4R sender.
59210052B is an '01 M900 sender, superseded with 59210053A.

It's a tremendous longshot, but perhaps the PO swapped a set of SBK heads on.
Are your belt covers carbon or plastic?

[Speeddog]

Can you post some pics?

Underside of tank
Frame and rear of tank area
Under tank stuff; airbox, battery, top of rear cylinder head

[corndog67]

Belt covers are carbon.  But according to the dealer, this bike has about $6000 in accessories on it (I know, I feel like a chimney with so much smoke blowing), but it's got carbon covers on the belts, the rear hugger, radiator shrouds, tailpiece behind the seat, side covers, Leo pipes, and Ohlins with the hydraulic spring adjuster, race tech forks, DP chip, performance air filter kit, little billet turnsignals, a top clamp with some motocross bars on it, just all kinds of stuff.   That is one of the reasons I bought it.  

So, what do you think, wrong gas tank?  Wrong fuel pump wiring (is that the fuel pump sending unit, as shown in the online parts fische?), bent hanger for the tank hinge (it doesn't look bent, no flaking paint), any and all ideas will be appreciated.  

Thanks Again, Robert

[corndog67]

I'll see if I can figure out how to get some pictures on here. 

[Speeddog]

This wiring to head interference isn't normal for S4's.

Perhaps the PO fitted an '00 or '01 M900 tank, although AFAIK there would be other interference as well, hence my asking for a pic of all the stuff under the tank.

I can't imagine the frame or tank bracket being bent enough to cause this, but again, pics may help.

<sidebar>
Carbon belt covers, front fender, and rear hugger all were carbon on S4 from the factory.

[Speeddog]

Some pics, from the OP.

Something doesn't look right, but I can't put my finger on it.

[needtorque]

I just went and looked at mine and the setup looks identical. (04' s4r)  My sending unit falls just reward of the cylinder head though.  His cylinder heads appear to be stock the lines fall in nicely with the radiator shroud cutouts.  The only thing I can think of is either the tank is too far forward  somehow or it is indeed the wrong tank.  I think it is the incorrect tank personally.  It is the only thing that makes any real sense.