i have a 1985 fj1100 and it doesn't seem to fire on left two cylinders? any ideas where to start???
i bought it foolishly and thought it was running right, until i painted the headers and realized the paint never changed on the left two pipes, there is no heat therefore no fire?? does one cdi run two cyclinders next to each other, or do i have a carb problem?
I think irishluck should be able to help you out!
He knows all about this issue...
ok so i have spark on far left cylinder, so it's obviously a fuel issue or carbs i think?? i have pod filters and 4 - 1 headers with a shortie exhaust plugs are all new!! should i rebuild carbs? the engine was just rebuilt by the previous owner? did i get ripped or what?
Spark is routed from two coils. One fires 2+3, one fires 1+4. The one you're seeing fire on is 1 (l-r as you sit on it).
The coils fire two cylinders at a time, one appropriately and one spark is wasted during the exhaust stroke. Rationale is that two coils are cheaper than four.
Starting assumptions : You have fire on 3 and 4, to start. Now it sounds like you are just missing on 2, if 1 is firing also.
So, to start. Swap the 2 and 3 wires to the plugs. If that moves the cold cylinder to 3, I'd suspect that the spark wire, cap, or something in the coil between the outputs is bad.
If swapping 2/3 doesn't move the cold cylinder (#2 still not firing), then you are likely not getting fuel to it. Pull the plug and smell it, if it smells like gas the plug is bad. If it doesn't smell like gas, the carbs are gummed up (most likely the pilot jet and idle mixture circuit).
How long has it been sitting? With the proper combination of crap gas and staying parked, carbs can get crappy in a week or less. If there's rust and crap in the tank, they can get killed off even quicker.
ha yeaa i know a little about this one. As far as i member your left coil should be on cylinder 1 and 4 and your 2nd coil on 2 and 3 (if im wrong correct me)
check that first and make sure those are hooked up right, if so, then you got maybe some bad wires or something
idk how to really check if engine rebuilt or not but try to turn the crankshaft with a wrench and see how it feels and sounds.
mostly its prolly going to be the carbs, they may have sat for awhile, may have bad gas. tear into them and see what ya find.
So I've found the left two cylinders only fire at 3000 rpm I screwed around with the carbs a bit it still don't idle right though
did you open the carbs up at all and see if gunked up?
Dustin,
Be sure your coils are well grounded before you "tear into" your carburetors. The coils ground an a painted surface, install a star washer and retighten the ground just for the hell of it and see if that helps.
ETA; This is assuming you have a "firing" problem. Test with a uninstalled well grounded spark plug, the spark should be bluish.
Do I need a carb kit before I start tearing into them I think they are just gunked up?
And where do I start tearing in? The top cover first? Yeah I have spark no problem there??
well me, id start by taking the bottom of it off, thats where you'll find your jets and such that would be gunked up, and i never used a rebuild kit for mine and my carbs still work fine. its recommended to get a new main jet and gasket if its gunked but they can still be cleaned if ya got an ultra sonic machine or something along those lines.
Hi Dustin, welcome to the site.
Please don't follow any advice offered by that Irishluck boy, he's not quite right in the head.
Andy B, Slow Old Guy and Randy from RPM(among many others) would be your best bets, listen to what those experienced men have to say and you should be fine.
Your machine worked once, it will work again.
nope, aint gota listen to me, listen to the guy who wants to talk crap, thats a great thing to do
If you can troubleshoot it to the carbs (which is what it totally sounds like, incidentally), the guide you want to follow is here (http://www.fjowners.com/index.php?topic=655.0). Explains the lot.
I strongly suggest buying this (http://www.rpmracingca.com/proddetail.asp?prod=carbkit&cat=24) kit, also. It'll make your life...oh... a zilliontybillion times easier if you ever need to go back into the carbs again.
ok so the carbs are spotless, not a drop of gunk or dirt, plugs are getting wet, small spark off plug wires, is it possible motor is screwed? it doesn't seem to have any leaks such as head gasket, etc, it seems to fire on all 4 cylinders around 2500 rpm, is it possible it just needs to be driven, hasn't moved in two years?
Next step is run a compression check on the engine. and then run a valve clearance check. It sounds like you might have a few tight valves.
Hmmm, good idea Kim but for now, maybe try to answer a couple of things before you start with the valves and compression tests.
How do you know the carbs are clean?
Did you take them apart and clean them or just look at the outside of them?
The more info you can provide, the better the prognosis.
Cheers
Quote from: gauthierdustin on May 12, 2011, 08:42:18 PM
ok so the carbs are spotless, not a drop of gunk or dirt, plugs are getting wet, small spark off plug wires, is it possible motor is screwed? it doesn't seem to have any leaks such as head gasket, etc, it seems to fire on all 4 cylinders around 2500 rpm, is it possible it just needs to be driven, hasn't moved in two years?
So far, so good. As above though, you mean the insides of the carbs are clean, rather than just the outsides, right?
Clean on the outside doesn't mean clean on the inside. Rember that rule or you'll eventually catch gonnorrhea, but that's another problem entirely (penicillin helps).
If the carbs are internally clean, with particular attention being paid to the pilot jets (the little bastards buried next to the main jets with a really, really small orfice size), the choke circuit (the hanging down brassish tube that sticks out when you remove the bowl), and the idle mixture area (the screws normally covered by plugs on the top, nearest the engine side), then the carbs qualify as clean enough to run decently.
However, what you're describing if it's running on all four at 2500rpm and up is an absolutely perfect example of plugging pilot jets. Like I said, the metering orfice in them is on the order of "really goddamned small", it's a hole with a diameter of perhaps 0.018" or thereabouts... I've got reasonably young eyes, and I require sunlight to be able to see if it's clogged or not. Reading glasses and one hell of a light source are helpful, but if you're in your 30's your friends will wonder about you if you store them in plain sight on the workbench. Don't ask why I know this.
Most likely, a few hours spent with a can of carb cleaner and this (http://www.fjowners.com/index.php?topic=655.0) guide will correct the problem. Get two cans of carb spray, incidentally, it's not uncommon for me to totally drain one and not quite finish. Do not use wire to clean the jets, they're made from brass and really easy to scratch internally, which screws the metering up. Nylon bristles pulled from a brush work, compressed air works better, but just blowing the hell out of them with a concentrated stream of carb cleaner usually swings it also (explaining why I use so much when I do mine).
Alternately, if they're clean internally and you don't catch gonorrhea from them, I struggle a bit to troubleshoot from there. I'd start with draining the tank and using absolutely fresh fuel from a known good source (BP, Mobil, Shell), making sure the plugs are new or damn near new and gapped appropriately (if the spark is weak, dropping the gap some can help you figure out where the weak link is), and failing that, break out the compression tester. If the motor fails a compression check, a leakdown check will help explain what's wrong.