Fuel pump not priming - M796

[jonzi]

Hi All

Pomp1 has been advising, but right thought I would open it to the wider audience incase anyone has had the same issue.

A few days ago my bike didn't start in the morning, so I connected it to the optimate and it started fine, and I managed to get to work.

On the way home it was fine, but I ordered a battery, this is the one that came with the bike is 5 years old.

Went to work the next day, bike started fine in the morning, but wouldn't start when I went to leave. Ended up getting a lift from the AA.

They tried to jump start it, but the fuel pump wasn't priming.

Bought a new battery and fitted and still having the same problem

I have checked the fuses, checked the fuel relays and checked that the pump works.

Max suggested to check the voltage on the wiring side, which I have tried to do but might be doing it wrong.

Has any one had problems like this before?

Also, does any one know what point does what in the fuel pump plug?

[Dirty]

Tried swapping out the pump?

[jonzi]

I dont have a spare.

I run 12v through the pump and it worked. I dont think it's the pump.

[Dirty]

Is the pump getting 12v with ignition on?

[jonzi]

I can't work that out.

My multimeter is not registering anything when I stick the probes in the holes. But this could be that my mm probes are too fat to get in to the holes.

The wiring diagram I have is sh1te. I can't see the colour codes on it, so don't know what hole in the plug does what.

[Dirty]

Get some thin wire and stick those in the holes (rip apart some broken electronic thing, you'll find suitable thin wires to keep for such occasions)

[pompone]

How did the AA tried to jump start it exactly? Btw if you need to check s female plug you can remove the red bit for ease of access..

[jonzi]

How did the AA tried to jump start it exactly? Btw if you need to check s female plug you can remove the red bit for ease of access..

Panels off tank off jump leads on battery

[slob]

Tried swapping out the pump?

tried swapping the two black relays over?

Panels off tank off jump leads on battery

oh dear

[jonzi]

Yep relays swapped and tested with 12v and a multimeter

[Dirty]

I'm still taking bets on it being the pump :)

[jonzi]

I'm still taking bets on it being the pump :)

If the pump is pumping when I put 12v across it, surely it can't be the pump that is borked?

[Albie]

Something is not telling the pump to pump then.

[BRH]

OK, might be a long shot but worth a look.
Remove the head light and check the mass of wire's that come from the clock's and run down into the bike, they are all bound together and rub on the head stock, slowly wearing through and course all sorts of electrical problems.

[Lucas 796]

Another long shot. Are side stand and kill switch wires OK !!!!

[slob]

recheck fuses 5 & 6 from left
5: 20A = Injection
6: 5A = ECU

going back to a recent conversation, is your switchgear properly earthed

[jonzi]

Another long shot. Are side stand and kill switch wires OK !!!!

I have put the side stand up, on a paddock stand.

Kill switch is on, haven't checked wires.

[jonzi]

recheck fuses 5 & 6 from left
5: 20A = Injection
6: 5A = ECU

I'll do a continuity check on them tonight.

[Dirty]

If the pump is pumping when I put 12v across it, surely it can't be the pump that is borked?

Well I'd agree it's not the odds on favourite and should you find it's not getting volts with ignition on then yes, problem elsewhere. That said I've known all sorts of strange issues with pumps. They can look like they are working but don't when under load.

[jonzi]

Defeated

I will take it to RC in a week. Max, expect a call.

I have tried checking the voltage from the plug wires, there are 2 pairs.

One of them isn't working when earthed. The brown and white wire from the plug. But I can't see where this goes to. My wiring diagram doesn't show colours as it's not high enough resolution.

It looks like it goes into one of the relays, but when I tried a continuity test from the relay to the plug I get nothing, so I dont know if its broke or I am looking at the wrong place.

Cheers for your help kind sirs.

[Lucas 796]

I think the brown \ white wire from the fuel pump plug goes to the engine management relay and the black is your negative wire .if you have 12 v on the brown\ white at the E.M. relay when trying to start but not at the pump then you could like you said have a break in that wire.Could you try running a temporary wire to substitute the brown\white ???

[jonzi]

Ok so back to this.

I have now properly tested the brown and white wire on the pump plug end, all I am getting is around 1v. When I test at the relay I get 12v.

Is there anything in between that would cause it to drop?

[Dirty]

Are you getting 0v then 1v when you switch on?

Sounds like a break somewhere.

[Darren69]

Either that or the relay isn't closing properly, but if you've already switched that out then I'd agree that a break is most likely.

[Akita Boy]

I had a very similar problem with the S2R, check the wiring going to the fuel pump where it exits the bottom of the fuel tank. My issue was where the resin seal of the tank was over the years of the tank being raised/lowered the wires had very slowly started to break inside the plastic sheaf.

So it looked ok, and if they were bent in the right way they're complete the circuit and the pump would prime and the bike would work fine. But then, without warning, and in various situations. (Ie stopped, on lock to lock at roundabouts, under hard acceleration/breaking) the wires would move very slightly, break contact and it'd cut out.

Took Al at Proteam ages to find the fault, as the poxy thing would never fail when he had it! But eventually they failed completely and he quickly tracked the problem down.

A new fuel pump fixed the problem.

Good luck tracking your gremlin down!

[jonzi]

Fuel pump is fine, I have connected that to another battery and the bike then runs.

I have by passed the wire that I think is the one that goes to the fuel pump from the relay and it works.

It looks like a dodgy wire in the loom somewhere.

I guess I now need to split the loom open and trace the wire.

I have something like this holding the relays

http://www.ebay.co.uk/itm/BMW-E30-E24-E31-E32-E34-Relay-Mount-Holder-Socket-16501-/171366288148?pt=LH_DefaultDomain_3&hash=item27e63a0b14

How do I get the spade sockets out, without breaking the holder?

[StevieL]

Push a small flat blade screwdriver down the cutout in the middle of each terminal from the relay mounting side and the terminals will drop out, if you need replacements they are 1/4 or 6.35 mm Lucar terminals, if you have trouble finding them pm your address and I will pop you some in the post. Rather than cutting into the loom I have used a bait needle to pull a new cable in with the minimum of fuss, it does require a steady hand and the battery disconnected just in case you stab something on the way through atb Steve

[Lucas 796]

To remove most terminals male or female they will usually have a locking clip built into the terminals, so you need to release the clip with a thin but strong spike or needle. Go inside the holder opposite end to the wire and release the clip whilst pulling slightly on the wire.

Beet me to it. As above.

[jonzi]

Great thanks Stevie and Lucas

Don't suppose anyone knows what the plugs are called on the fuel pump end, so I can get a replacement one.

Cheers

[jonzi]

I worked out what connectors to use.

All I need now is to order some cable.

What rating wire should I get? I have found some where that does 16.5 or 25amp wire.

The fuse is 20amps if that helps?

[Mr Gazza]

I have a spare fuel pump plug from an earlier model than yours...The type that enters the tank via the fuel level sensor.
It clips into the pump inside the tank.

I'll send you a picture tomorrow if you like...Free if you want it..The plug, not the picture....Well the picture aswell actually..:scratch:

[Darren69]

I've used these in the past for misc electrical bits n bobs

http://www.vehicle-wiring-products.eu/

but you could probably use ebay these days

[BigOz]

Not sure if it helps but the 696 manual shows the Bn/W wire going between the ECU on pin L1 to the fuel pump, starter solenoid, injection relay, coils and injectors. If the 796 is not different you should be able to continuity test between those points.

Big ugly image here (http://www.bigoz.net/IMG_0885.jpg), I have the 696 service manual in PDF if that might help.

Andy



I worked out what connectors to use.

All I need now is to order some cable.

What rating wire should I get? I have found some where that does 16.5 or 25amp wire.

The fuse is 20amps if that helps?

[jonzi]

I like what you have done there Oz. Gonna get this printed off tomorrow and see if I can work this out properly.

[BigOz]

Got some decent images from the PDF:

Wiring diagram (http://www.bigoz.net/M696_09_en2.jpg)

List of the numbered components (http://www.bigoz.net/M696_09_en.jpg)

[jonzi]

I have bought two lots of relay clips and neither fit

Does any one know what these ones are called and where I can get them?

http://i.imgur.com/JOVXXDU.jpg
http://i.imgur.com/ES2GP6l.jpg
http://i.imgur.com/nrhJcZL.jpg

[StevieL]

Typically Italian - bastardise a common part to make life difficult. Google Durite Auto Electrical and select the Duriteparts option, you want the relays and flasher units section and you will find a standard bulkhead five pin relay housing, make sure you get the 6.3mm terminal type as they also do them in 4.8mm. They also stock the Superseal connectors that are used for the pump connections etc. atb Steve

[jonzi]

Good lord, this is proving to be hard!

Durite are trade only!

And that relay box looks to be for one relay, where as the one that is on the bike takes two relays in one socket box.

But I guess I could buy two and just split them.

[StevieL]

Will have a rummage in the morning Jonzi pretty sure I have a four way block left over from a job, the individual holders slot together to bank up as many as you need.

[jonzi]

That would be awesome. Thanks

Might give them a ring and see if I can persuade them to help me out anyway. Just incase

[StevieL]

Jonzi you have pm atb Steve

[jonzi]

Turns out it was the datatool alarm

Some wiring was fried, which has blown the immobilizer part of the alarm, either from the AA trying to jump start it, or being too close to hot stuff.

Alarm pulled out and bike works again.

[jerry]

thats a bummer JONZI