Fuel Pump - 3 second priming was bypassed

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DoubleDuc
Posts: 34
Joined: Mon Jul 28, 2014 2:12 am
model: 907 I.E.
year: 1991
Location: Va, USA

Fuel Pump - 3 second priming was bypassed

Post by DoubleDuc »

I took my 907 to a Ducati Dealer/"mechanic" in Yorktown, Va - I won't mention any names, paid them about 4 grand to overhaul my bike. They basically replaced superficial parts and broke other things while not fixing main issues. I am mechanically inclined, but that's about it - I fixed everything they couldn't in two days.

So my question: They bypassed the 3± second (on) priming of fuel to make it constant (always on); they told me why, but it didn't make any sense, and I just figured they knew what they were talking about/doing, (knowing what I know now, I wouldn't let them work on my lawnmower). Would anyone have any speculation on what they did, why, and how to restore it to original 3 second on and then off.

TIA



"I used to think I was smart, until I realized the people around me were just dumb."
Sheff928
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Joined: Tue May 20, 2014 3:04 pm
model: 907 I.E.
year: 1992
Location: UK

Re: Fuel Pump - 3 second priming was bypassed

Post by Sheff928 »

On my 750 SS IE this is controlled by one of two relays which sit next to the ecu. One of my went fubar recently and the fuel pump ran constantly, at least until it failed to run at all. Replacement relays cured it.
I'll check later to see if my 907 ie has a similar arrangement.
Kindest regards,
Kevin
-----------------------------
907ie 1992
ST4s 2002
750SSie 2002
Cagiva Gran Canyon 1999
Norton Commando 750 1971
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higgy
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Re: Fuel Pump - 3 second priming was bypassed

Post by higgy »

My guess is the blew you ECM which controls the ground to the fuel pump relays so to get the fuel circuit running without a prime all you need do is ground the wire after removing it from the ECM harness This is only the way it works on a 907 the rest ( 750 Sport and Paso and the 906)are simpler and do not require a prime. All fuel injected Ducati work in a similar fashion to the 907 at least those with a P7 or P8 ECM


any way pull your ECM connector and check to see if the wire to pin 28 has been removed. If they have been really sinister they could have added a ground anywhere between the ECM and the relay and left the wire in place as it would have no effect once the ECM diode has been blown


have to find my injection manual to be sure of the pin number but I think it is 28 that grounds the relay(s) and also handles the 3 second prime
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
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DoubleDuc
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year: 1991
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Re: Fuel Pump - 3 second priming was bypassed

Post by DoubleDuc »

I like how you put sinister, let me elaborate: They failed to put the cup filter underneath my 800 new pump which allowed all debris to enter and ruin it, after the 4,000 overhaul. The bike wouldn't start the next day. I took the bike back multiple times for a throttle sticking problem, 6 hours charged to my account for soaking the throttle cable (400 dollars), I fixed it with one turn on the throttle body nut and some WD-40.
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paso750
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Re: Fuel Pump - 3 second priming was bypassed

Post by paso750 »

you won`t mention names but you can nod if it`s Redline Performance in Yorktown, VA. At least I`m assuming that after reading these comments: http://find.hamptonroads.com/reviews-re ... wn-va.html
If it is this shop imo it should be mentioned just to prevent others do have the same experience.
4.000 is alot. Did that include a complete engine rebuild, paintjob etc. ? You could get another 907ie for that money or a P750 and a 906 together.

G.
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DoubleDuc
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Re: Fuel Pump - 3 second priming was bypassed

Post by DoubleDuc »

paso750, nod. I realized I could get another bike, but I was hoping to get 'piece of mind' for that kind of money.
oceanhunter
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Re: Fuel Pump - 3 second priming was bypassed

Post by oceanhunter »

The only piece of mind I find is to do the work your self,no one else will put the love and attention into what they do more
and your time is usually cost effective!
"keeping the shiney side up"
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higgy
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Re: Fuel Pump - 3 second priming was bypassed

Post by higgy »

Not true, there are Ducati shops around that know how and will do so cost effectively, most are private shops but there are still a few dealers willing to do it, they are not your typical Duck Shop for sure

I am however of the same mind set as you DIY I have many good techs get insulted when I turn them down but it is my affliction not their insult
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
oceanhunter
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Joined: Sat Jan 15, 2011 9:09 am
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Re: Fuel Pump - 3 second priming was bypassed

Post by oceanhunter »

I meant no insult to those in the trade,we have a ex Ducati works mechanic in town and he is more than helpful
it is just that i get as much enjoyment(may be more :thumbup: )working on than riding said machine :wacko: .
You call this an affliction :?: my wife calls it something totally different :lol: .
"keeping the shiney side up"
krisstek
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Re: Fuel Pump - 3 second priming was bypassed

Post by krisstek »

have here 907's schematics.puel pump an mae module are connected at the same relais.
marelli ecu grounded this relais via pin 28 and it drives pump and coil module(mae)
this is a normally connection in every fuel injection sistem.
why?because a fuel inj sistem work at 3,3.5 bar and fuel pump must work only when engine running.
this is a safety sistem,if have a crash and engine stops,ecu dont drive relais and fuel pump go in off mode.
think ,in crashed car,a broken fuel hoses ,squirt fuel at 3 bar...it's very dangerous.
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higgy
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Re: Fuel Pump - 3 second priming was bypassed

Post by higgy »

Yes , all of what Krisstec points out is true and the ECM can be repaired by removing the blown diode and replacing it with a more robust diode for lass than 10 bucks USD even cheaper if you have a good supplier nearby. In the States I use Allied or more often Newark Electronics
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
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