Hi Guys,

Pulled my RS out the shed after is been in there for about a year. Not run. Did have it stripped down somewhat, throttle body for new rubbers and air box out.

Put back together and fresh fuel but no start. no fuel at injector rail. Can't recall if you could hear the fuel pump running?
I can't hear it. Checked voltage at the plug. (4 wires?) could only get a reading on the white one with ignition on of 5.5 volts (12 at battery)

Get ignition lights and does turn over OK.

Could the pump have gone duff?

Cheers

depends which side of the tank connection you tested

the 4 pin plug socket combination is a known fail point

have you tried crimping the socket part connectors just a little ? so that it makes better contact ?

also clean those connections , and use deoxit  on them after the clean

of corse the pump could have an issue ...

with ignition on and if you get at least a few turns of the motor with the start button , you should hear the pump running  for about 1.5 seconds after pushing the button  and the engine turning ... the hall sensors are important to keep the pump running as it detects the motor turning

good luck

Thanks Charlie99

Have checked fuse etc and good. Cleaned up connection with cleaner. Have put ear to tank and turned on ignition. Can hear relay and a wrrrr in tank which stops after a second or so.

If I take fuel lines off rail and turn over I assume I should get fuel at the front one  (from pressure regulator)?

Have only put in a couple of ltr in and empty tank, would that be enough fuel ?

Thanks

One way to test the fuel pump is to disconnect the line from the tank to the rail at the rail.  Point that line into a bucket and hit the starter button.  Fuel should flow into the bucket.

Of course if you have a fuel pressure gauge that would be preferable.


Another thing you can try to see if it's a fueling issue is to spray some starter fluid into the airbox.  That should be enough to start the bike and have it run for a second or two.

If you suspect low fuel then put the bike on the side stand (in neutral) and try to start it since the fuel pump is on the left side of the tank.

Thanks Duck,
Tried turning over with fuel line off but nothing..

What I did was put the beer intake over the end of the pipe and suck. Nothing, put ignition on and still nothing, pressed starter at the same time and still nothing.

Could regulator valve be an issue?

The fuel flows from the tank to the rail and then through the rail to the FPR so you should get fuel regardless of the FPR'condition.

If you only put a little gas in then I'd recommend taking the gas cap off and looking in the tank to make sure there's enough fuel to submerge the bottom of the fuel pump.

the pressure regulator is at the back of the fuel rail throttle bodies , and goes there after passing through the fuel injector rail  leaving the rail from the back

so the rear connection on the tank Is the fuel out   the front is the return

the fuel out goes to the front of the fuel rail


just so we get it right

could the fuel filter in the tank have become blocked , or a rubber line has split  from the pump to the filter , then filter to outlet pipe ?

possibly worth having a look inside the tank , but fuel filter sounds like a good place to start ????

Thanks guys,

Had it the wrong way round..

Run out of time but in the first instance, will get more fuel in it tomorrow after work

Where it the filter? The four screws under the tank?

Thanks

Open the gas cap.

There are four screws around the rim that hold the gas cap assembly on.  Use a GOOD screwdriver and downward pressure to break them free.  The tank and screws are dissimilar metals and if the gas cap has not been removed recently then corrosion can build up in the threads and if you're not careful you can strip the Phillips head of a screw and cause a bunch of unnecessary work.

Once you have the cap off you will see the fuel filter.  There's a short 2" hose at the front of it.  Remove that front clamp from that hose and detach the hose, then you can pull the fuel filter out since the hose that goes to the back of it is pretty long.

Remember which way the arrow on the fuel filter is pointing (towards the smaller hose) and remove the clamp that goes to the long hose.  Then try blowing through the fuel filter in the direction of the arrow.  It should be pretty easy. If not then you'll want to replace the fuel filter.  (which you might want to replace anyhow since it's a good routine maintenance thing to do if you don't know the age/miles of the old one)

Do not buy a BMW fuel filter as they are way overpriced and a fuel filter is a generic item. Ask your K buddies down under what brand and part number to get.  You need a decent metal one, not a cheap plastic one.

Thanks Duck appreciate the info

Will get into it tomorrow. I'll let you know how I go

A Ryco Z200 will do the job fine. It's from a VL Commodore

charlie99 wrote:

so the rear connection on the tank Is the fuel out   the front is the return

the fuel out goes to the front of the fuel rail

The fuel hoses is routed differently on a 4V (which this is) than a 2V, Charlie.

The tank outlet is connected to the rear end of the fuel rail and the front of
the fuel rail is connected to FPR and then it returns to the tank.

The fuel doesn't care which direction it goes through the rail, but it could
be some problem with the hose lengths if trying to connect them as a 2V.

good point inge , I had considered that but didn't see any reference to 4 valve type immediately .

just checked the signature now  yes 91 = 4 valve  ....doh !


but the "fuel out" indication did help some what ?  giggle

Also, because the bike is a four valve, the fuel pump is energized for about two seconds when the ignition is switched on.  That explains the whirring noise when you turn on the ignition.

Think I might have found the problem!!!

Pump will not turn, tries but no go. Hate to think where that rubber residue has gone

Ah Ha the gooey pump rubber trick. have a hunt around there is plenty here about that.

ouch..!   yes could explain a lot ...giggles

Looks expensive..

I assume the pump is a sealed unit and cannot be stripped to clean up?

well the pump can be stripped and cleaned  ...but unpredictable results  achievable

probably best to search for something compatible ...and cheaper

or soak the pump in some form of solvent to free it up

unfortunately the rubber isolator most likely needs replacing regardless ...unless you can find another way of resolving . mounting the pump , not always do you need to consider that the 52mm pump is the only alternative , many have opted for something different

good luck

many posts in the forum about this issue ... there is a search engine in the "portal page "  .

Thanks Rick and Charlie,

Having a browse via the search, as you say lots of stuff on the subject

you could likely find a old pump out of a ford or even commodore from the wreckers yard ...many euro designed cars used similar

I'm running an old Toyota corolla (89 model efi 51mm ) pump for the last 6  + years and 80,000 +kilometers  , without the slightest issue ,,,although it sits a little higher in the tank and runs out of fuel slightly before the bosch unit ...lol  but for $20 dollars ...has done well

The old VL dunnydore fuel pump will do the trick 6 or v8 just need to put different terminals on the wires.  You will need a new rubber vibration damper but avoid ethanol and it lasts for ages.
https://www.euromotoelectrics.com/

Hi,

I just through a whole myriad of checks and found my fuel pump was bad. the piss in the bucket wouldn't have told me there was a problem. The bad pump was not putting out enough pressure but you're beyond that point now! This is the pump I put in:

Pump specs:

Facet-Purolator FEP2042 In-Tank Fuel Pump, 1991-1993 Ford
Escort, 1986-1995 Ford Taurus, 1988-1994 Lincoln Continental, 1986-1995
Mercury Sable, 1991-1993 Mercury Tracer

http://www.motobrick.com/index.php?topic=7066.0

http://www.motobrick.com/index.php?topic=2058.0

https://www.k100-forum.com/t2019-fuel-pump-replacement

Glenn

Thanks Guys,

Cannot get my pump to turn, does try.... Have not stripped but have soaking in a solution of thinners.

Have also gone for a cheap option on Ebay.


Now cleaning out tank!
Since pump didn't run am hoping it hasn't pushed that rubber gunk through the system

Chuck it, it will cost more in thinners than a new pump.

Advice taken Rick...

On to the scrap pile !

She lives!!!
Managed to get her started up but was a bit of a mission.
Would not even try with any choke whatsoever.
Choke off and slight throttle, still no go.
Leave throttle closed and choke off and would fire for a few seconds then stall.
Kept at it and eventually had rough idle.
Gave a very little bit of throttle and eventually it picked up.
After warming up seemed OK. Not ridden.

Funny that it did not like any choke at all and took a while to pick up?

Could it be the fuel mixture?

Thanks

The choke is only a fast idle, the ECU controls the start mixture according to air and engine temperature.
As soon as you touch the throttle you cause the ECU to change the starting parameters. This is the same for most EFI engines, many cars tell you not to touch the throttle when starting from cold. I have a BMW car and if I even breath on the pedal it gets really difficult to start. From what I gather the ECU thinks it's a warm engine start and changes the mixture from what it would have for a cold engine.
Have you had the manifold stubs off and renewed the O-rings and made sure the rubbers under the throttle bodies are good and the clamps are tight.

CraigNZ wrote:She lives!!!
Managed to get her started up but was a bit of a mission.
Would not even try with any choke whatsoever.
Choke off and slight throttle, still no go.
Leave throttle closed and choke off and would fire for a few seconds then stall.
Kept at it and eventually had rough idle.
Gave a very little bit of throttle and eventually it picked up.
After warming up seemed OK. Not ridden.

 great to hear

keep at it ...till we see you on the road finally enjoying thr "k" experience  that we all in here enjoy

Thanks guys,

Have had throttle bodies off to fit new rubbers but will recheck as am going to take off again to clean parts up.

Numpty here forgot to plug the throttle sensor back in, only noticed after I had stripped the pump out of the tank again so cant test yet.

Maybe that would that cause delicate starting issue?

Dog isn't much help......

Seems I now have another issue.
Got the pump sorted but now doesnt power up when I put the ignition on.
Pump does work with direct current to it.

No supply to the yellow wire. No supply at the female yellow on the plug either?
There is a 7.5 volt supply to the white at the plug.
Fuse OK. Not sure which relay is fuel?

A bit stumped. Worked fine when I tested a couple of weeks ago

Any suggestions much appreciated

The pump will only start when you press the start button on a K100 and K75 where the K1100 will start when the key is turned on. Both will run for 1.5 seconds or will keep going if the engine is running.

Thanks Rick

Ill have to check that out.
Maybe am wrong but thought I heard the pump fire up for a second when I put the ignition on previously?

Cheers

Just tried testing whilst starter button pressed...nothing.

My mistake a 16v engine will be the same as a k1100 and go when the key is turned on. Does the neutral light work and try with clutch lever in.

Thanks again Rick
Been researching on this great site and think I need to check the relay (FI?)
Which one is it?
Thank you

Oh and yes, neutral light on and nothing with clutch in

Check the sidestand switch.....if isn't allready disconnected and bypassed.

Cheers Inge,
Not sure if it is. Will check out tomorrow.
Strange (or maybe not) that was good a couple of weeks ago and not moved since..
Saying that have done a bit of wiring work around the head light, but all seems in order.
Just doing a tidy up..

CraigNZ wrote:Not sure which relay is fuel?

From an online BMW 16v K100RS manual (speckled version):

Thanks for the help guys....

Is there a numpty head of the week award?

I didn't have the ECU plugged in!!

CraigNZ wrote:Thanks for the help guys....

Is there a numpty head of the week award?

I didn't have the ECU plugged in!!

Yep that'll do it every time.

CraigNZ 

At leasr you have owned up to it 
We all done these things 

Bet  you have learnt more about your bike 

Sure have Matthew,

How to spend all afternoon checking wiring, testing fuses, testing relays, pump in and out the tank several times.
Then start again because I had run out of ideas!!

All good practice...