Fuel Pump......not

OE pump is running at 75 psi/5 bar (should be 50 psi/3.5 bar) but replacement pump is also running at similar high pressure (symptoms = lumpy/dying/stalling tickover, similar low rpm fuelling and poor cold/hot start up) - unlikely that both pumps have the same/similar fault but about to try a third.

Anyone know if the electrical supply, ie too many volts/amps, could cause the pump to run at too high a speed/pressure? If so, surely the regulator should compensate anyway?

Have noticed that the tank is now being pressurised but that's a separate issue (?) and shouldn't cause the pump to run at a higher pressure (?).

Tyre pressure but not fuel pump pressure.........

Your rectifier is working ok? Does seem odd that both are putting out 25 psi more than they should.

injectors may be too blocked? it can't get the volume through so the pressure skyrockets

Both fuel filters on both pumps are new and/or OK (the OE pump filters have been in for 30k plus miles and are as clean and in good condition almost as new) - had considered injectors but below 3k rpm the exhaust gases smell very rich and above 3k rpm the fuelling seems OK (with Jocke's/James' map but not the OE Akra which has glitches between 4 -5k and at 6k, similar to before the fuel pump issue) - the pressure is high throughout the rev range and if the injectors were blocked, I would have thought the fuelling would also be poor throughout.

Will try the third pump today.

when did you last properly clean the injectors?

Have never cleaned the injectors but, again, regulator should still maintain 50 psi/3.5 bar.

Reg/rec seems OK, at least there are no other symptoms of it failing - could a faulty relay provide too high an amp supply to the pump?

Rugby delaying any testing/replacing at the moment.

Seems to be a few double posts on here at the moment.

Throttle plates have little to do with fuel pump pressure........

check pm

It has to be electrical doesn't it? Can't think of anything else that could make 2 pumps push out 25psi more they are meant to. Unless the gauge is reading wrong of course.

I would test the fuel pressure guage to make sure it is reading correctly. If the fuel pressure guage is reading correctly at 5 bars the only thing that can make the fuel pressure that high is a faulty fuel pressure regulator, it is either blocked or faulty.

When you renewed the pump & filters did you renew the pressure regulator?

No 'cos you can't buy the regulator alone - unless the two pumps have exactly the same fault, which is unlikely, I'm inclined to agree with Klinck - swopping out the relay first.

Have tried two pressure gauges.

A relay is just a switch if the pump is running the relay is working, if the pump was not producing the pressure then I would be looking at the voltage & amp draw of the pump, 2 different pumps same regulator same results? No mater how much voltage you throw at the pump the fuel regulator is there to control the pressure.

Me thinks I would remove the regulator & pressure test it.

Two different pumps with two different regulators (and two different pressure gauges)- understood re relay but will swop out anyway.

Hotbrakes may be right that the poor fuelling symptoms may have nothing to do with fuel pressure but I want to sort this out first.

This is becoming surreal...............................

Swopped out the fuel pump relay - no change,

Blew thru' both fuel tank vents/drains and fuel cap with compressed air - no change, tank still pressurises but can't tell whether it's positive or negative - have now removed rubber 'connector' between cap vent and base plate which seems to have sorted that out but..........

Swopped out Pump 2 for Pump 3 - initially ran at 50 psi/3.5 bar, the specified pressure, with a tickover far lumpier than with the previous pumps but after a couple of restarts and short engine runs, back up to 75 psi/ 5 bar and the less lumpy tickover as previously.

So......................either all three pumps are faulty and running at too high a pressure or both fuel gauges are faulty and showing a consistently wrong high pressure for all three pumps.

I was still thinking that the fuel pumps could be being supplied with too many amps (not volts as I guess that's technically impossible) but have no idea what they should be drawing and, more importantly, even if they were spinning up to too high a speed, and therefore pressure, the regulators should maintain the right pressure.

I'm now thinking that the gauges are faulty (but with both showing exactly the same 'wrong' pressure?), that all three pumps are fine and that the poor fuelling at tickover and low rpm is due to something else entirely - cue Mr Z32 and injectors, Hotbrakes and throttle plates and/or someone and something else entirely.

Next step, though, is to check the fuel pressure on Pump 3 with (yet another) Pressure Gauge 3 'cos before I do anything else I'd like to see 50 psi/3.5 bar.........................unless the specified pressure quoted by KTM is wrong - has anyone else checked their fuel pump pressure?

For those rivetted to this thread and taking notes.............

Third pressure gauge shows 62,5 psi/4.25 bar for Pump 3 - current prognosis is that all three pumps are OK but all running at too high pressure (though varying figures) - KTM quoted figure of 50 psi/3.5 bar is correct and +/- 10% on this pressure OK but all three running beyond this - fuel pump(s) power draw OK - therefore throttle body fuel pipes/injectors partially blocked/failing - will be swopping out throttle body shortly (cheers again Cheesie) as next step.

Reconnected O2 sensors to try and reduce clearly over rich fuelling at tickover and low rpm - no difference.

Geek observation - fuel pump pressure regulator appears to maintain whatever the 'system' pressure is, whether correct/high/low, and not the quoted design pressure of 50 psi/3.5 bar.

Daily 75 mile round trip ride in this current state of tune makes life interesting..........

I feel your pain dude! Hope you can finally sort it.

No pain, no gain - 2013 1290 SDR next.

Brief update.....

All three fuel pumps and pressure gauges checked out - fuel pressure varies between pumps and gauges but consistently 'high' at 63-70 psi/4.5-5 bar, so view is that the pump(s) aren't the problem despite the over spec pressure.

Replacing throttle body made no difference.

Lumpy tickover symptoms have got worse but have made tracking down the problem easier 'cos it appears to be the rear cylinder not firing properly, as shown by sticking my ear next to each cylinder and a very low rear cylinder 02 sensor voltage on TuneECU.

So current guess is a failing plug (ignition coil checks out on TuneECU) - however..........the engine usually ticks over fine from cold and then becomes lumpier as it warms up which may be consistent with a failing plug but the engine runs fine above 3k without a glitch - never experienced a failing plug before but surely it should be worse, and not better, at higher revs?

All that other crap, BGC? Not crap my friend.

Sounds to me like your map is the culprit. Wouldn't be too concerned about slightly high FP pressure, the injectors are only going to allow so much fuel regardless of pressure. I'd be looking at your map and A/F ratio from idle to 3K where your symproms seem to disappear.

Good luck with your issues 47.

Both TBs synched and checked out.

BGC cleaned and greased. Different/same maps swopped out, with reset adaption and 15 min reset each time.

One of those problems that can only be solved by swopping out individual parts, one at a time.

I bought a new TPS, rectifier, and batter, cleaned and greased BGC and other components.

I'm hoping once I install all this stuff, and synch the TBs, my duke will finally run right again lol

Yep, cracked plug (brand new) and stick coil (relatively new).

63-70 psi/4.5-5 bar fuel pressure appears to be a red herring and swopping out the fuel pump, throttle body, etc a complete waste of time - unless the cracked plug and stick coil are a later, unrelated, problem and, once replaced, I'll still have the original problem of lumpy tickover, etc - still don't understand how a failing plug and coil works at high rpm and not low rpm/tickover, though....................................to be cont'd.

[quote="No. 47"]Yep, cracked plug (brand new) and stick coil (relatively new).

63-70 psi/4.5-5 bar fuel pressure appears to be a red herring and swopping out the fuel pump, throttle body, etc a complete waste of time - unless the cracked plug and stick coil are a later, unrelated, problem and, once replaced, I'll still have the original problem of lumpy tickover, etc - still don't understand how a failing plug and coil works at high rpm and not low rpm/tickover, though....................................to be cont'd.[/quote

Bad plugs do show up at tickover / low revs, just ask any TL owner!

TLs will foul plugs on cold starts, the bike will feel ok at high revs but run like a pig low down and tickover all lumpy or stall, the only cure is change the plugs,
The problem is worst if you dont have the fueling spot on,TPS set correct and throttle bodies balanced.....

I am sure SDs like fresh plugs to, mine was a lot smoother at tickover and crisper off idle after the last plug change, the plugs that came out were not fouled or worn either

Sorted with a new plug and coil stick - big thanks to Cheesie for the loan of a throttle body and the sale of a stick coil.

your welcome

You guys are scaring this old man to near death!!!! Please lie to me and say these issues are only few and far between. Just about to pull the trigger on a low miles SDR and really don't want to spend all the time wrenching on the bike.

Pull the trigger - mine's been raced, currently at 56k miles and I ride it every day throughout the year - you may/will experience issues but the solutions are on here.

KTM - Making mechanics out of Riders since 2005!

Just got to fix the flux capacitor.

And get your hands on some plutonium.

......Part Two - just spent 45 minutes on the side of the road near Brands Hatch with a stalled SDR and subsequent flat battery trying to restart - after 15 minutes of 'Zen and the Art of Motorcycle Maintenance' contemplation and checking, refilled the tank with fresh and cold fuel - started on the button and ran sweetly into London - have noticed of late poor running/fuelling when the fuel level drops to circa 2 litres and struggles to fire up after refuelling - no issues re pressurisation of fuel tank 'cos I've been there and removed the fuel cap mebrane, etc, so I'm thinking overheating and cavitating fuel pump........unless anyone can think of any other explanation.

Interesting that the Yuasa battery seemed to 'recover' from being unable to crank the engine, Soft 32 Dat 101, etc - will replace anyway, though, 'cos it only managed 4 -5 cranks before 'failing'.

have you changed the fuel filter yet,

D

Yep, swopped out pumps, both with new filters, seals, etc - not sure whether it's 'yours' or 'mine' in at the moment -
having owned TR6s for over 30 years, know a little about cavitating fuel pumps and current symptoms tick all the boxes - like I said in my pm, I guess this must be the next chapter.

S

dont know if this helps but read 28th april about the 3rd or 4th paragragh down http://www.superbike.co.uk/viewers/view ... 990R+(2008)

D

Thanks for that - I have a copy of that article (it wasn't enough to put me off buying one though) but had forgotten the reference to the fuelling problem (but not the phrase 'curiously fast Dave Wood').

It's not clear if the fuel pump or the sensor was replaced but if my sensor is failing, that would explain the lack of screaming normal for an overheating/cavitating pump - will check it out and replace if necessary.....................unless you have a spare one I could swop out before buying (£45 ! ) new.

S