Author Topic: Help!! Has anyone had this fault before? (Read 5515 times)

Scooby81 · « **on:** June 20, 2016, 14:55:40 »

Hi all.
I was wondering if anyone has had this fault before On the 2002 Vstrom? The bike idles fine and revs fine up to 6k as soon as it hits 6k it seems like it wants to cut out or missing badly. Even when riding it won't go above 70mph it feels like starvation but it has a new fuel pump in and new leads/plugs. The TPS is fine and no vacuum leaks. Does anyone have any ideas as to what could cause this? Thanks in advance for any help.

P.s
The oxygen sensor is fine too.

Fat Rat · « **Reply #1 on:** June 20, 2016, 15:01:54 »

When you say it has had a new Fuel Pump, is that the complete assembly or just the Pump?

SpikeTM · « **Reply #2 on:** June 20, 2016, 15:04:04 »

Possibly a regulator rectifier

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Scooby81 · « **Reply #3 on:** June 20, 2016, 15:07:46 »

It's a complete unit yes. The fuel supply is good. Is there a way of testing the rectifier to see if the supply is breaking down? It's strange that it's fine up to 6k then plays up even when stationery

Fat Rat · « **Reply #4 on:** June 20, 2016, 15:15:25 »

Have you done a pressure test? How do you know the fuel supply is good?

Scooby81 · « **Reply #5 on:** June 20, 2016, 15:24:08 »

I haven't done a pressure test yet no. I removed the fuel line with the tank lifted and the pump was throwing a good volume of fuel out. Compared to the old one.

Fat Rat · « **Reply #6 on:** June 20, 2016, 15:26:08 »

Have a read here http://www.v-strom.co.uk/smf/index.php?topic=28671.40

DesertStrom · « **Reply #7 on:** June 20, 2016, 15:32:45 »

Not sure if it is related to the Vee but had a similar problem on a K9 Wee, it turned out to be a connector behind the lower right hand side main frame spar was loose!

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Scooby81 · « **Reply #8 on:** June 20, 2016, 15:35:49 »

I'll do the resistance and continuity checks today. I did a just the TPS and according to what I found its responding as it should but I'll do the checks for piece of mind

kwackboy · « **Reply #9 on:** June 20, 2016, 18:13:47 »

Take a look at the secondary throttle butterflies. If they are not operating correctly this may cause the symptoms your are describing.
I'm pretty sure the regulator wouldn't cause these symptoms
Good luck.

Scooby81 · « **Reply #10 on:** June 20, 2016, 19:01:11 »

Is it the TBS that controls the secondary butterflies? They adjust and reset when I turn the ignition on. Is there a way to check they're positioned properly?

greywolf · « **Reply #11 on:** June 20, 2016, 19:08:40 »

The STVA controls the secondaries. The position sensors feed information on the throttle plate positions to the ECU but have a passive relationship to the plates. The cut off described is most often fuel related. A pressure check would be a good idea. Just make sure you can't staunch the fuel flow from the pump with your thumb. If the fuel pressure can force fuel out of the hose against thumb pressure, the fuel pressure is probably fine.

Scooby81 · « **Reply #12 on:** June 20, 2016, 19:23:53 »

Just going to check fuel pressure now. There seems so many possible causes. I'll have a look at the secondary bf's while everything is off

Scooby81 · « **Reply #13 on:** June 20, 2016, 19:57:11 »

I read somewhere that if I run a line from the fuel outlet on the tank and cycle to ignition on and off 3 times waiting till the pump stops running I should be getting about 300-350ml of fuel. Is this correct? I've done that test and the fuel is minimal a lot less than I got before I probably got 30ml after all three cycles!!!

Fat Rat · « **Reply #14 on:** June 20, 2016, 19:59:07 »

Did you read this thread? http://www.v-strom.co.uk/smf/index.php?topic=28671.40

Do the thumb test

greywolf · « **Reply #15 on:** June 20, 2016, 20:13:59 »

300-350ml for three ignition cycles is the correct amount. If you get much less, that will prevent higher revs. http://www.vstrom.info/Smf/index.php/topic,11603.msg124168.html#msg124168

Scooby81 · « **Reply #16 on:** June 20, 2016, 21:04:14 »

It's a hell of a lot less the fuel was no more that trickling out! Seems like the pumps is duff. I got no more than 25-30 ml after the three cycles. Even doing the thumb test I doubt there will be any pressure

Fat Rat · « **Reply #17 on:** June 20, 2016, 21:22:39 »

That's why I asked if you'd changed the whole assembly (inc high pressure filter).

It is possible to bypass it on the older models with a carefull placed drilled hole.

kwackboy · « **Reply #18 on:** June 20, 2016, 22:15:54 »

Did you change the pump personally or was it done by someone else .? The whole thing or an individual part. ?
Apply 12 volts to the pump connector live and earth and see how much fuel comes out after 30secs , should be around 1200ml.
If not , It could be a bad pump , blocked high pressure filter , faulty seal between the pump and the main filter or the main filter could be blocked also there is a pressure regulator seal that could be damaged.

greywolf · « **Reply #19 on:** June 20, 2016, 23:11:44 »

The pump is the entire unit with the possible exception of the float mechanism. I get the impression some here are referring to the motor as the pump. The motor is rarely a problem.

The typical problem is a clogged high pressure filter above the motor and, occasionally, the lower pressure screen below the motor. For an less expensive fix, see http://www.vstrom.info/Smf/index.php/topic,6105.0.html