fuel system problem???

VMAX  Forum

Help Support VMAX Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

nightfox85

Well-Known Member
Joined
Aug 30, 2009
Messages
77
Reaction score
0
Location
San Antonio, TX
we just had a huge rain here in texas and ever since then i bike runs fine for about ten minutes and then dies quick and hard, and will not start. the fuel pump also starts clicking before the problems start. then when i try to start it the pump clicks slowly. i dont know if its a fuel pump issue a line issue a carb issue or anything and i really dont want to pay for a shop to fix something i can do myself.
 
Could be water in the gas. Drain your fuel bowls and have a look at what comes out..

For the fuel pump there is a thread here describing how to service it - it's very straightforward.
Thread's called 'what to do if your fuel pump keeps on clicking'.

Also, you could have dirt in your fuel that makes the needle valves stick, dumping gas into the engine and flooding it. Can you smell gas at all when it misbehaves?

Finally, electrics could be a problem, we've seen TCI units go funny when they get wet..
 
ill check all those, what throws me off is that it runs great till it warms up then runs like a$$ till it dies, ill get maybe 5 miles and dead. the pump starts to click just before the problems start and whats weirder is it ran all day just fine after the rain but the next it was bad. it also get very noisy before and get what sounds like blowback in the carbs and one set on one side is hotter than the other like its running lean
 
I think crap/water in gas. Sounds just like how mine runs once the rust from the tank gets in the carbs. The pump clicking would also point at sticking needle valves, or just not closing properly because of dirt, which is what mine does.
After a good carb cleanup mine will run great for up to about 100 miles. Then it all starts going crazy again.
And guess what - it's always a lot worse once warmed up!
 
ya for sure sounds more like that, guess we got two same threads going on at the same time or at least same issues hahahah. good to see we are coming up with the same solutions
 
so whats the best way to keep it from comming back up later down the line.

Good question.. In my case I found rust in the tank, so I'm gonna replace it (I have a spare that's been treated) and treat mine too. I'm hoping that will help.
Also the flap on my Muscle Corbin seat is a bit on the short side, so it may let a bit of rain into the gas cap which can't be good either - I have a better flap but am yet to uncover the whole seat in order to get it replaced..

In your case I would try to keep the bike out of really heavy rainfall. :confused2:
 
Pull your fuel pump and disassemble it. There's a thread on here somewhere, I believe, on what to look for while in there.

There are two small rubber, spring loaded valves in it that need to seat. One on the intake side of the pump, the other on the outlet side. If the small rubber diddie gets loose from the spring, the pump won't keep up good pressure. If both get loose, the pump will lose all pressure.

Could be you are suffering from this type pump problem.

Water in the lines would pressurize the same as gas and you wouldn't hear the pump straining to maintain pressure.

Also, if when the bike warms up, you have a carb needle/seat not closing for some reason, that carb(s) will suck way too much fuel and maybe cause the pump to work extra trying to maintain pressure, also causing that carb(s) to flood over and kill the bike.

Start with the pump. It is relatively simple to get to under the seat, and easy to disassemble and inspect.
 
ok so i disasembled all the good stuff, drained the bowls and noticed a slight amount of what seemed to be water (all i could tell is it was heavier than the gas as i settled on the bottom), ran it on idle for a good while felt good, then died. i noticed the biek straining to start so i decided to run it with jumper cables.. ran at idle great for an hour no issue with, took them off drove it and it was fine for five minutes. i also noticed alot of moisture possibly fuel on the lines from the pump so i will try to make sure they are connected. side note the battery has been charging for almost four hours and still is not fully charged would a low battery also produce these symptoms or should i go ahead with the pump investigation.
 
see when its fully charged and if you can put a load tester on it otherwise might as well get a new batt, not too much and wont have to worry abou\t it for next season. you might still have water in the tank if some came out of the bowls. think on the other thread i mentioned to use some seafoam it will will help and hook up a jerry can of gas and run the bike, see if it will die like that, narrow down your problem if it is yoru tank or lines.
 
if u def think u have some water , dry gas should help out a lot. i've had it work wonders on my old truck.

also, a battery can produce all sorts of problems. i've seen the strangest issues resolved by getting a new GOOD battery (ody, oem, etc)
 
I would definitely replace your battery - it sounds like it's dying or dead. I bought a Panasonic gel one for under $50 and it's doing fine do far.

If you don't have too much gas left in your tank, you could have a go at draining it. There's a drain plug at the bottom of the tank. Then put fresh gas in and see how it goes..
 
ill try the seafoam first after replacing the battry, i will try the dry gas as well however i do have to reminde that i am in texas and a majority of pumps dispense at least 10% ethonal.
 
oh wow, i just notice naughty g post i was un,aware of a drain plug, ill drain it and go high octane and seafoam it. then ill go from there.
 
I wouldn't go high octane if I were you - the Vmax is a low-compression engine and like 87 best.

Stick to 87 and add a little SeaFoam, then you should be ok.
 
I wouldn't go high octane if I were you - the Vmax is a low-compression engine and like 87 best.

Stick to 87 and add a little SeaFoam, then you should be ok.
+ 1 no need for high test man reg will do fine.:punk:
 
Back
Top