Fuel issue, intermittent.

[Jim417mx]

Hey buys, been strugling with this issue for months, I'm ready to take it to the dealer for only the 2nd time in its life. I have an 07ltr fully built mx quad, I just rebuilt the motor, everything is in spec, it just wont tune out with the pc3. Sometime you can sit there on the laptop and add so much fuel, that you can watch black smoke come out the exhaust from being so rich, other times you add all the fuel on the laptop and no smoke comes out at all and it pops and runs lean, and either way it wont tune out to be 100%. On some of my previous posts, I refer to the tune as "running like a 400ex with a pipe".. it barely lifts the wheels off the ground. We have gotten it to run good twice, where it would be crazy fast, then you park it and ride it with the SAME tune 10 mins later and it runs like crap. I bought a new pc3, new throttle body w/ injector, cleaned out my whole fuel system except the regulator because the screws will not un-screw out of the bottom of the gas tank, new spark plug, different types of fuel, checked tps, . i checked A LOT of stuff.. etc... no idea where to go.

[bigbad400]

intake boot leaking? soundls like got some air sucking in someware once in a while...


or your pressure regulator is bad and u just need to buy a tank with a good one in it if you cant get yours apart. thats what i wuold start with and a good clean air filter.

[turdboy]

It sounds to me 100% it's your fuel pressure regulator. As far as I know this is becoming a common problem with LTR's. I know when mine went out it was a total headache. We checked everything but the regulator which was the problem the whole time. First check your fuel PSI, and if its not spraying the correct amount of fuel get yourself a new regulator. I personally did not install mine. I had ROSSIER put mine in and they said it wasn't the easiest. May be better off swapping tanks like someone mentioned above. I would put money on it that this would solve your issues. Don't take it to the dealer.

[blholtz]

The fuel regulator is an easy change, not hard at all. And it is either that or your fuel filter.

Quick check for the fuel regulator. Take it off the tank. Disconnect the all lines to the regulator. Put your finger over the return outlet and blow into one of the high pressure openings. If you can blow through and hear it the regulator is bad.

[panici33]

Dyno?

[Jim417mx]

Awesome thanks guys! Fuel filter is new, like i said I have gone through EVERYTHING in the fuel system except the regulator because the bolts are stripped into my gas tank, I tried everthing to get them to back out, but I am going to have to drill them out. And as for the dyno, find me a quad dyno by chicago and I will gladly go there :D


EDIT: As I go on ebay to order a new regulator, the fuel filter housing comes up when I type in fuel regulator, ... so just to be 100%, the regulator is the T thing under the gastank with two 8mm bolts , correct?

[blholtz]

Originally posted by Jim417mx
Awesome thanks guys! Fuel filter is new, like i said I have gone through EVERYTHING in the fuel system except the regulator because the bolts are stripped into my gas tank, I tried everthing to get them to back out, but I am going to have to drill them out. And as for the dyno, find me a quad dyno by chicago and I will gladly go there :D


EDIT: As I go on ebay to order a new regulator, the fuel filter housing comes up when I type in fuel regulator, ... so just to be 100%, the regulator is the T thing under the gastank with two 8mm bolts , correct?

You are 100% correct. Good luck You might be better off just getting one through the dealer at least you know it will be good to go.

[turdboy]

If you are looking for a dyno near chicago and are willing to drive a few hours hit up ROSSIER. They have a dyno and they are actually the onles who discoved that my regulator was bad. If I remember right Charlie said thay had to drill out the bolts for mine as well. Anyways, he will get you tuned in perfectly.

[Jim417mx]

Rossier as in rossier exhausts? Either way shoot me their number/website. I will gladly take my quad somewhere with a dyno to get it tuned, I'm sick of it !!!

I just spent an hour drilling out my regulator, pulled it off, and ... of course... I CANNOT blow thru it, I loosened the cover with the 2 phillips screws and then I can blow thru it. Does the actual part inside the regulator come out once u take the cover off? Anything to check to see if its gummed up?

EDIT: I forgot to mention, I have noticed the regulator dripping fuel out when the gas tank is pulled off the quad... SOMETIMES, not always... so I'm guessing this is why my quad runs good SOMETIMES , and not always....

I finally feel like I'm getting somewhere with this quad, after over 50 hours of messing with it to try and make it to pell city and getting nowhere

[Limited Z_400]

When you had it to the dealer, did they check fuel pressure?

[Jim417mx]

the last time I had it at the dealer was about 2 years ago, so I coudlnt give you an answer..

[blholtz]

did you change the fuel injector when you cleaned the fuel system? I haven't, as of yet, figured out how to clean the injector itself out. That might be your issue to. I know you said you changed everything, but I am just asking.

Miss firing injector might cause the same symptoms.

[bigbad400]

if you have a problem with your injector just replace it. if you go messing around and poke a hole out too big you will always have problems... there not cleanable for a reason. i asked suzuki about this. they made them to be replaced because its too easy to mess them up. in a car its alot more forgiving... but the easiest way to keep things like this from happening is quality gas and a oz of seafoam in your gas when you fill up. seafoam is amazing. its a total engine cleaner... i have a 95 polaris 500 snowmobile that i have never cleaned the fuel injection system on it, just use seafoam and i have never had a fuel issue. everything is clean when i check it out. never bean rebuilt, never nothing. just keep seafoam in in the summer and never let it sit more than two weeks befor i fire it and move the gas through it once... same with my quads in the winter. start them once every two weeks and use seafoam.. never had fuel issues with my stuff... i call it preventative maintenance.

[blholtz]

Thought that might be the case on the cleaning of the injectors.

But the info on the Sea foam is a help, thanks I am going to look into it.

Do you use an ounce per tank on the quad or an ounce in your refill can?

[bigbad400]

i use about 2 oz in a 5 gallon can. always run premium gas in my toys too. its not clear on the can says use more for cleaning less for maintenance... can use it in any internal combustion engine. there is a trick if you put like 2 oz in gas 2 oz in oil and 2 oz in your intake start it up it will smoke like hell and blow all the carbon build up out. and then run great. i had a friend with a gmc sonoma that would not start and idle unless we feathered the gas and poored some gas in the intake to fire it up... we did this trick and in 20 min it would idle smooth and it would start on its own... we basicly filled the neighborhood with black smoke... but it worked and still runs. amazing trick. you will just be dumbfounded how much carbon can blow out of even a new car.... use quality gas.

[turdboy]

Just google rossier engineering. Yes they same ones that make the pipes. They have an in house dyno.

[Jim417mx]

Originally posted by blholtz
did you change the fuel injector when you cleaned the fuel system? I haven't, as of yet, figured out how to clean the injector itself out. That might be your issue to. I know you said you changed everything, but I am just asking.

Miss firing injector might cause the same symptoms.

I pulled my injector out, and pulled the screen out, and there was gummed up fuel sitting in there, that is the reason behind me replacing my injector, i DO NOT reccomend trying to "clean" your injector by taking it apart, just run fuel injector cleaner through your tank like bigbad400 said.

Just to clear things up, yes I replaced my injector, I bought a complete throttle body with injector off ebay with VERY low hours on it off a 08' ltr and it ran the exact same, it fired up, and seemed like it fixed it.. then I park it and it starts acting up again. I have replaced EVERYTHING in the fuel system EXCEPT regulator and fuel pump. I guess if this new regulator doesnt work, all thats left is the fuel pump, if I try a fuel pump and a regulator, and it still does it, then its going to the dealer because that will mean the whole fuel system has been replaced.

Things I have replaced and/or checked so far.

-NEW Fuel filter - no change in performance
-Clean low hour Throttle body off an 08' with injector - ran good for a couple mins then back to no power
-Used Coil - no change
-NEW PCIII - no change
-NEW Spark plugs, tried regular NGK , And Iridium - small difference
-Plug gap - OK
-Fuel , tried 100, 93, and mixed, runs a little different, not major.
-TPS , checked and set to spec
-Air filter - clean
-Vaccuum Leaks - none
-Compression and valves - in spec, motor has fresh 13:1 with ATP head freshly rebuilt.
- I just pulled my head off and re-did all the valve seats and cleaned 99% of the carbon in the parts washer - I have yet to see how it runs, waiting on fuel regulator.

[Limited Z_400]

Any time I have LTRS with running issues I stick to the basics first.
I do the following checks
1. check FUEL pressure.43 PSI 2. leak down test 5% or less (compression test does NOT count)
3. check for failure codes past and present.
I know you will have to take it to the dealer for most of the tests but for an hours labor it will save you lots of guessing.
Also check the pulse coil for resistance and output (if possible)
Most common problems:
1-clogged fuel filter
2-faulty fuel controllers and most cases improperly adjusted controllers.
Hope this helps
Good Luck.

[Jim417mx]

After spending $1000+ on parts, it turned out to be my regulator, oh well, live and learn. Thanks again guys. Glad to finally get to ride this new built motor.. this thing spins thru every gear on the street!!!

[turdboy]

Feels good to finally figure it out huh? Thats's one of the disatvantages to EFI. Once something takes a crap it's harder to pinpoint the problem. When my regulator first went out we were digging into the topend and checking valves. But just from reading on here and on the LTR site I think the whole regulator thing is fairly common. I wonder what is making them go bad?

[Limited Z_400]

Originally posted by Jim417mx
After spending $1000+ on parts, it turned out to be my regulator, oh well, live and learn. Thanks again guys. Glad to finally get to ride this new built motor.. this thing spins thru every gear on the street!!!
WOW :(

[blholtz]

Originally posted by Jim417mx
After spending $1000+ on parts, it turned out to be my regulator, oh well, live and learn. Thanks again guys. Glad to finally get to ride this new built motor.. this thing spins thru every gear on the street!!!


At least you know those parts are fresh so you shouldn't have any problems in those areas.

I have had regulator issues in the past, until I switched to using nothing but VP C-12 in my quads and then the regulator issue went away. Not sure why but it did.

Before I was using high octane fuel from gas stations.

[bigbad400]

yea wow...:( sry to hear that but ahh... when it comes to fuel injection your best bet is to run the diagnostics. first and foremost. thats why they make trouble codes and diagnostic stuff on them stock... if you will recall the first post was by me.. and i told you to change your regulator... i dont get to do this much but... i told you so. lol:D

[blholtz]

I'm gonna bet that the $1000 in parts was put on the bike trying to figure out what the problem is. I went back and read the start and it was posted that he had been trying to figure this out for months.

But at least it is fixed now. I do believe that this forum is to help other LTR owners with problems.

And once the weather turns nice where you are take that fresh runnign machine out and give it hell.

[Jim417mx]

Damn right it feels good! And you guys are right about the $1000 in parts that I replaced, I'm 100% OK with the fact that my whole fuel system has been replaced as well as a new coil and throttle body, injector, fresh valve seats, etc. I live breath and sleep quad MX, I'm the type of person that New parts boosts confidence levels when racing , MAN this thing RIPS!