Incorrect idle and stalls

[Red Ballz]

My RC (2002, all stock minus power commander) is surging at idle from between 1000 - 1500. Its not constant. It will get so low that it will stall. Also, it seems to be surging when traveling below 20 mph.

I have pulled the plugs and checked the spark. The air filters are clean as well. I checked all the wiring, looking for pinched wires and loose connections. I was running a stock dan kyle map, now I have a PC stock map, neither seems to change it, anyways, the PC isn't supposed to change the fueling at idle.

I plan on pulling the PC tomorrow to see if its the problem, but I don't expect it to be, again it doesn't change the fueling under a 0% throttle. Friday, I plan on running some injector cleaner through it, and also changing the plugs (they appeared fine, but still...).

Any input is appreciated.

Thanks,
Morgan

[johnyisthedevil]

86 the injector cleaner. don't bother, the only way to truly clean an injector is to pull them out and have them serviced. it's more likely something else anyway.

a little more info if you would please. has the bike just recently started doing this, or did you buy it that way. did you do something to the bike before it started. when did you first notice it. does it do it all the time or when it's just hot or just cold. have you checked for vaccum leaks? does it do it with the fuel lid open?

a little fyi the stock gearing is real tall so it is common for them to surge at low speeds and low rpm. unless of course you have a realy good map for YOUR setup.

first thing to check though is that the tank vent tube is not pinched somewhere.

[Red Ballz]

Originally Posted by johnyisthedevil

86 the injector cleaner. don't bother, the only way to truly clean an injector is to pull them out and have them serviced. it's more likely something else anyway.

a little more info if you would please. has the bike just recently started doing this, or did you buy it that way. did you do something to the bike before it started. when did you first notice it. does it do it all the time or when it's just hot or just cold. have you checked for vaccum leaks? does it do it with the fuel lid open?

a little fyi the stock gearing is real tall so it is common for them to surge at low speeds and low rpm. unless of course you have a realy good map for YOUR setup.

first thing to check though is that the tank vent tube is not pinched somewhere.

It first happened a month and half ago. It only happened once. Then starting last week, it started happening alot. The only thing that I have done to the bike is the PC, and that was a few months ago. The temp doesn't seem to matter much, but it is more common at higher temps, 175 or so. No, I have not checked for vac leaks, but I will go and check for them in a little. And I will try it with the lid open. Right now I am going to go check the fuel pressure regulator.

[johnyisthedevil]

if you don't have one there is a service manual posted in pdf form on this site. do a search and down load it. fuel pressure reg is definitely a good place to start

[mspeedman]

disconect pc to eliminate possiblity,if same... then plug back in

Check the vacuum, syncronize the throttle bodies or at least check, should tell you if one cylinder is causing the issue. Also check slack or lack of from the throtle cables and linkage.

Good luck

[DesperateSP2]

Originally Posted by mspeedman

disconect pc to eliminate possiblity,if same... then plug back in

Check the vacuum, syncronize the throttle bodies or at least check, should tell you if one cylinder is causing the issue. Also check slack or lack of from the throtle cables and linkage.

Good luck

Agree with that. I may also add that fuel filter may be a culprit (luckily it can be swapped with relatively little effort).

[pannetron]

My 2003 had some similar symptoms and a new baro sensor fixed it. YMMV...

[bensexcessbikes]

Silly question, but is there a FI light on the dash illuminated?

[Red Ballz]

Originally Posted by bensexcessbikes

Silly question, but is there a FI light on the dash illuminated?

Nope.


But the problem is solved:

Well, not solved but known. Its the pressure regulator, I think. Reading some of the other threads about similar problems, it was suggested to disconnect the vac hose leading to the regulator, and see if fuel flows from where it attaches. Sure enough, I disconnected the vac hose, and had gas pour out all over my hand. So unless I am greatly mistaken, its the problem.

Thanks.

[RVTMAVERICK]

Hello,.. Hey Red Ballz,.. FYI... even though the Spark Plugs "Can look Good" they can still be on their way out,.. for mileage!... So,.. IF you've had them in there for over 7, to 8,000 miles... get them out of there and replace them with some Nice Fresh NGK's or whatever ones you like.

Let us know what you find out please... again, even though the "main" problem could be something else... Swap out your High mileage SPs

[varium]

Originally Posted by Red Ballz

Nope.


But the problem is solved:

Well, not solved but known. Its the pressure regulator, I think. Reading some of the other threads about similar problems, it was suggested to disconnect the vac hose leading to the regulator, and see if fuel flows from where it attaches. Sure enough, I disconnected the vac hose, and had gas pour out all over my hand. So unless I am greatly mistaken, its the problem.

Thanks.

You beat me to it. I was just about to suggest checking it. Its either going to be the FPR or a vacuum leak on the TB's or a pinched vent hose on the tank. Would check in that order as the tank hose would be a real long shot. If not the FPR it should be a vaccum leak around the TB's. With putting on a PC you may have knocked something loose, somethign got pinched, or a dry hose got cracked.