Nomad 1500FI running rich no idle

[BigJohn8229]

I have just recently had an issue come up on my nomad that has me baffled. I originally noticed it started idling very rough and started back firing when down shifting while riding one night. So as soon as I got back home I looked for the carbon ring in the throttle body. I didn't see any but I cleaned it out with a tooth brush anyway.
The next day I decided to ride it to work with some sea foam in the tank, but just with the idle screwed turn in a little bit to keep it running. About halfway to work it started idling great like it always has so I adjusted the idle screw and was happy as can be. After work, as soon as I cranked the bike it was doing the whole rough idle till shut off mess again. 😔😡 This time I ended up having to turn the idle screw all the way in to keep it idling so that I could get home.

So, now I have cleaned the throttle body again and found that if I take either of the tubes off of the idle speed control valves it will increase the idle and if I take both off it idles up very high but that would be correct since I have the idle screw all the way in. I also removed the plugs and they were sooted up from running rich. I am assuming that there would be an issue with the iscv's not opening but I am not sure where to start looking for the issue. Any help would be greatly appreciated!
Thanks
John

[mrtelefoneman1]

Welcome to the forum, John. You may take a minute to introduce yourself in the new members section.

To get some help with your problem, you should offer more info.

Is it stock? Do you have pipes, processor, aftermarket air cleaner?

DL or MAS will prolly chime in with some help if you offer more info about your scoot. Good Luck

[DragonLady58]

Well, Kinda sounded like a fuel problem, since it started idling better with the Seafoam....
Sounds like your either sucking air/vac. leak, tps/computer being thrown off, or you might have sucked in some garbage, ie, dirty gas....
What year is your bike?, when was your last tuneup?, did it do this right after a fillup?, or right after some repair?, What type of EFI controller?....
We also gotta know if its bone stock or does it still have the emissions crap still hooked up? Mileage? We need info....

[BigJohn8229]

I apologize for leaving the info out. I bought the bike used about 4 years ago and haven't had to do anything except service it until this year. Last winter I replaced the clutch spring and plates. So in all honesty I don't know all the particulars. The bike is a 2004 year model with 13k miles and it appears to be all stock except for v&h exhaust. My initial thought was that it was fuel related until it changed right back the next time I cranked. It started right before I filled it up with fuel. I am very appreciative of the quick response!!! Thanks again!

[DragonLady58]

Well, all of a sudden, black sooted plugs on a EFI system? Open your gas cap, take a wiff....smell like gas? Is it strong like it should be? Get a turkey baster, get a piece of 3/8 or 1/2 gasline about 6" long, should go in really, really tight....toward the front of the tank, suck up some gas. Squirt in into a clear plastic container. Get about 2 or 3 gulps and then hold it up to the light while you swirl the container. See any mess floating around in there? Still smell like gas? Diesel?
Now, pour a little into a metal container, like a tuna fish can.
Take it down to the end of your drive way, light it with a long stick with a touch of charcoal lighter fluid soaked into end of stick. Does it burn slowly, like kerosene? It should PFFFT! And burn really fast, almost scaring you! If it doesn't, you got bad gas.
Let the rest sit in the container for a hour or so....if its bad it will start to seperate.
If gas is ok, start your bike with aircleaner off. Will it idle now?
Get back with us....could be injectors aren't closing like they're supposed to....we'll talk you thru it....could be several other simple things also....
Is there any black smoke coming from your mufflers? How long since you changed your plugs and aircleaner?

Usually if it starts acting up right before you fill it up, theres something in your fuel, your tank screen is stopping up from crap, or your fuel pump might be getting weak. Because your plugs are sooting up, I believe your fuel/air ratio is being thrown way off....

[ringadingh]

Scrub the throttle body with carb cleaner and a toothbrush, that will probably fix it. Pay attention around the butterflies.

[BigJohn8229]

Ringadingh: I have cleaned it twice since it started with a tooth brush and still no change. I was really hoping that would fix it the first time I tried it.

DL: I drive a diesel pick-up so I am always very cautious with the bike to make sure I get high octane gas. The store I filled up at has a totally separate diesel and kerosene pump. I will have to pull a sample and see if there is any trash or water in the bottom of the tank. So I think part of the culprit of the sooted up plugs was from me checking it out. I have ran it with the right side dog bowl off and also checked the air filter, and it appears to be clean. The only thing I have found that changes the idle is when I take one of both of the hoses off of the idle speed control valves that are inside the right air cleaner cover. I did notice when those hoses were undone it seemed to make it run more rich and it did black smoke a little when I would rev the engine. This is what I think contributed to the soot on the plugs. I don't remember the last time I replaced the plugs so I have them in the truck and plan to get 4 more next time I am by the parts house or motorcycle dealer. Just out of pure curiosity why are there 4 plugs abs not just the standard 2. Thanks for all the awesome help!

[BigJohn8229]

When riding the bike runs out great like it should at any speed above idle besides a back fire when down shifting to a stop. The only issue is at idle. Could there be a connection or electrical issue not allowing the idle speed Control valves to open and let the proper amount of air in? In a past life before I got a career I was a small engine mechanic, but we never dealt with any efi systems. At this point I almost wish it just had an adjustable carb.

[DragonLady58]

Well, sounds like everything is ok, from what your telling me. One thing you ought to consider, is taking all the emissions crap off your bike. The backfire or pop your hearing when your stopping is the emissions control system, most likely. Could also be a exhaust gasket leaking. That backfire is cause by air getting into your exhaust system, either by your emission system or a leaking gasket.
I would get a can of carb cleaner, get that toothbrush, and make sure that intake tract is squeeky clean, while your going over it again. Open your throttle wide open, and clea right behind where the throttle blades close.
Gadgets site has a comprehensive article there for removing your emission junk. Your engine will run cooler, have more pep, in general, run better.
If you have the V&H Bagger duals, check your rear pipe, you could have a crack in the pipe, that would cause your backfire also. Get a flashlight, follow your rear pipe down, look at it good. They have a tendency to crack, its best to check them out every-so-often.
The hoses will leak going to the reed valves (if you order coasters, you'll be removing them and will block them off), those air valves has hoses too, that can leak also. Just order a set of coasters, take off all the hoses and cap them, disconnect the air solenoids....you'll enjoy your bike alot more....
I would also make sure your engine ground is good and clean also. Make sure your plug wires are in good shape and the connecters in the caps are good and tight. If you can't remember changing your plugs, its due for some fresh ones.

The reason for the 2 plugs per cylinder is to lower emissions, and make the engine burn cleaner, also helps performance....
The EFI systems on these bikes very seldom give trouble. If they do, its usually from neglect or component failure. These bikes start up fast, run great, and very seldom have problems like your experiencing. Be sure to check all your vacuum lines, to make sure theres no vacuum leaks. Hoses can get old, hard and brittle.
Did your bike backfire just before you had all this problem? Just before filling up? I've seen this blow off vacuum lines and solenoid hoses before....

[BigJohn8229]

I will check the exhaust hopefully this afternoon and take all the emissions stuff off. The fact that it runs good above idle but will just barely stay running has got me confused. Usually if it runs rough it does it at all speeds. I will update as I try these suggestions

[Rasta]

I am having the same issue on my 2004 Nomad too. I had swapped out the motor end of last year and it was running good. Parked it for the winter while I continued to ride the 2000 Nomad. When spring came around I decided to get it out of the shed. Started up fine and I let it warm up for a while. After a while I got on it and revd it a couple times then the idle went to hell, eventually died. Restarted and still wanting to die. Took it around the block and like your runs great going down the road but when pulling off the gas it sounds like the kill switch was hit and feel my body lunging forward. Cleaned throttle plates, that did not help. Tried adjust idle and throttle cables too. No good. The next time I ride it is fine but will start to act up again. I did notice the same thing with the idle solenoids and was going to swap them out since I have another set but couldn't find them....finally did a couple days ago but will wait to do them.

[DragonLady58]

Originally Posted by BigJohn8229

I will check the exhaust hopefully this afternoon and take all the emissions stuff off. The fact that it runs good above idle but will just barely stay running has got me confused. Usually if it runs rough it does it at all speeds. I will update as I try these suggestions

Probably vac. leak somewhere in the intake tract. You could idle it up to where it'd stay running, and squirt some carb cleaner thru a straw all around the FI Throttle body and hoses. That will tell you if you have a leak or not.
When you hit the vac. leak with the carb cleaner, the engine will clear up and the rpms will climb, almost like your reving the bike.....
I would also run another can or 2 of Seafoam thru it to help clean the injectors, throttlebody, etc, good....

[Ridefree]

A little while ago I changed out my throttle body due to a bad TPS . I forgot to attach the small 1/4" hose to the top of the TB that goes to the pressure sensor and T's ( plastic ) off to the fuel pressure regulator . I had the same symptoms you are describing . Worth a look ... http://www.kawasakipartshouse.com/oe...90761/throttle

[Rasta]

When I parked it after the last ride I had run the fuel as low as I could so that I would pull the fuel tank off and I was going to look for anything down there. So that is a good point to check. Thanks. Probably wont happen until about August.

[BigJohn8229]

Originally Posted by Ridefree

A little while ago I changed out my throttle body due to a bad TPS . I forgot to attach the small 1/4" hose to the top of the TB that goes to the pressure sensor and T's ( plastic ) off to the fuel pressure regulator . I had the same symptoms you are describing . Worth a look ... http://www.kawasakipartshouse.com/oe...90761/throttle

Well I did some troubleshooting this afternoon. I first checked the exhaust pipes. Found no cracks there. I then drained as much of fuel as I could get out. I didn't see anything alarming in it and it was still good. I couldn't get it all out though. So I removed the tank to check any connectors and look for possible vacuum leak. I found that "T" that ridefree is talking about and the leg the goes to the sensor that is mounted up on the top of the frame had been rubbed through. I thought boom I have found the issue. I got a piece of vacuum hose at the lodge local parts house and put it all back together. After getting it back together I fired it off and no change what so ever. Still barely idling. I hate to admit it and I will take all the advise, but is it time to take it to the dealership or a shop?