[Carolynskii]

So I've got this project and had it to the point where I could get it to start with starting fluid. I worked on the fuel pump and reinstalled and cleaned some connections because everything is filthy but now it won't even start with fluid. All I get is a pop backfire.
Here's a video of my spark. I put a brand new plug in but the spark is still a crappy yellow and not bright blue. I also traded out a coil with no improvement.
I've never had one do this. Any ideas why my spark is crappy?
13 Honda 420 fm
If it matters my solenoid is dead and had to use a screw driver to jump the posts.

https://youtu.be/FKUbqu0ngVg

 

[JohnnySolo]

Solenoid being dead shouldn't matter. What brand spark plug did you get? Do you still have box it came in, if so post pic.

 

[retro]

Is it intermittently misfiring? I can't tell... Does the spark look stronger cranking it with the recoil?

 

[Carolynskii]

Plug is spec
Retro it probably looks misfire because of me holding it lol but with good ground its steady. But steady yellow not the bright blue im use to.
Recoils are an accessory on newer bikes so it doesn't have one.
I checked battery connections and fuses cleaned and dielectric grease. All fuses have 12volts on each side.
I even went and got some actual starting fluid instead of the brake cleaner I was using in case this bike was a snob or something but no improvement just a pop..
Ima have to get the dang manual out lol it's funny I don't mind doing it for others but for myself I get pretty whinny about it lmao

 

[LedFTed]

did it run before it was a project? can it be a bad ground? what that yeller beastie behind the green one? i know a smidgen about my 2000, not so much about everything else. ;~} lol

 

[retro]

If it isn't intermittent I wouldn't worry about it because it looks fat enough in the video. In the dark that spark might look a lot more blue...? If it is breaking down inside the chamber when compression pressure is highest, then its a problem though. I assume its an NGK plug... not a Champion...?

Its probably time to dust off the FSM though, like you said. I don't like those newer PGM-FI systems because certain parts of the fuel delivery and fuel controls system are dependent on parts of the ignition control system and vice-versa. Interdependency adds several unnecessary complications to those inherently dumb and cheap electronic controls.

You are getting pretty good with those 420s... I've noticed.

 

[retro]

One little gotcha I've been seeing more of lately still leaves me confused as to why... but if one leg (one winding of the three) of the stator windings is found to be bad, the ECUs start acting very weird and unpredictable. Swapping known good ECUs in only seems to change the weirdness. Bad regulator/rectifiers can cause similar problems for those ECUs too. Now anytime I see something happening that don't make any sense to me, I check the stators and rectifiers. One time it was just water inside the plug that got me. Food for thought...

 

[Carolynskii]

Yep I've got a new spec NGK plug.
But yes as you can see these tortured bikes keep me on my toes with all their weirdness and backwards pistons and such lmao
Ima do some more investigating tomorrow with a fresh head after coffee lol I was mad at it today and walked away.
It actually came with the wrong ECU on it lmao and i got a used right one from ebay.
I hope the dang thing didn't burn out!
Had to put a new starter and swapped the fuel rely just to get it to the point of possibly starting up! THEN when I hit the start button it wouldn't quit turning over by itself (but didn't start) and I had to disconnect the battery to make it stop! Lmao I assume that was because of the solenoid because the solenoid died after that.
This all sounds crazy but it's typical of the abused bikes I buy.... Just weird random crap happens and previous owners leave me with an insane puzzle to solve.

 

[Carolynskii]

did it run before it was a project? can it be a bad ground? what that yeller beastie behind the green one? i know a smidgen about my 2000, not so much about everything else. ;~} lol

Led dat yeller beastie is ma parts bike.
But ma green one wasn't running it was a basket case. I usually like to at least get to start before I tear em down and do a parts order lol

 

[retro]

Yep, I see a gazillion of those messes around here too. One thing that really gets under my skin are the farmers that hack up the wiring harnesses and swap in old car parts on everything they own because they are too tight with their money to fix things right. They blame everything that happens to them on the wires. Some of these guys I can't say no to when they ask for help... they are friends and neighbors. I can't seem to convince very many of them that they should please call me before hacking on the wiring... not after?

One of the locals here finally figured it out for himself last summer when I told him to drop of the machine. Because I was going to rewire the entire rig and if I ever saw another cut wire, or old car parts spliced into it again on that machine, that I was going to quit answering my phone! LOL

Tough love works I guess... because after I finished rewiring that machine he asked if he could drop off his other one for the same rewiring job. Hes tickled that everything works now, especially both of those charging systems. LOL

 

[Carolynskii]

Son of a ..... it's my used ECU / PGM-FI that caused a weak spark. It worked when I bought it but now is no good. I'm concerned if something caused it to go bad or just bad timing.
I check the manual for testing procedure but quickly realized I don't have a peak volt tester. However it did basically say if the test under performed then it would be the ECU and since my spark underperforms I figured I'd check it.
I had an ECU for a different bike laying around and tho that ECU won't command the fuel pump to run I plugged it in anyway I was able to spray starting fluid and she fired right up.
Crap!!!!!!!!!!!!!!
I guess I'll order one and go ahead and tear down the engine without seeing it run. I hate doing that tho but it does have signs of distress so here I go blindly.

 

[LedFTed]

Led dat yeller beastie is ma parts bike.

just about got your accent down.lol ja'us ta'bout

 

[Carolynskii]

^^^^hahahahahaha

 

[Carolynskii]

I'm back dang it
I swapped the ECU/PGM and no change. Still have weak spark.
I've swapped the rectifier no change. I've swapped the coil no change. New spec plug. I've swapped the computer no change except that I can put a wrong ECU on it from another 420 bike and it will start.
Melatv do you have time today for testing? I have a multimeter but not a peak volt meter. I don't know of any other components that have to do with spark but I do have a parts bike to swap stuff.
Any help would be great thanks

 

[JohnnySolo]

Have you tried putting the plug in another bike to see how its spark is? Or take coil off and put on other bike. Keep doing with whatever will work on other bike till you find a flaw. Best I can say

 

[misterclean59]

I don't check spark by the color. I check it by how far it jumps to clean metal. I'd say 5/16 of an inch or 8 mm is good enough. 10mm or 3/8 is even better.

 

[shadetree]

ummmmmmm..just a tip : ecu's/c.d.i's..well..they don't have a dang thing to do with how good the spark is ?!!!..lol. the spark comes from the stators, then THROUGH the c.d.i's, to the spark plug coil ( which also controls the spark ), then spark plug. soooooooo..odds are..your stator is weak.

 

[misterclean59]

I just watched the video. I'd say your spark is very good. It must be a fuel delivery problem because you said it starts with starting fluid.

 

[Carolynskii]

Misterclean I can only start it with fluid using the wrong ECU for it so doing that must bypass something. It's gets a bright blue spark with that ECU but that ECU will not engage the fuel pump because it's the wrong one. It won't start with fluid using the correct ECU.

Shade it will start with a wrong ECU makes me think not the stator?

 

[misterclean59]

Misterclean I can only start it with fluid using the wrong ECU for it so doing that must bypass something. It's gets a bright blue spark with that ECU but that ECU will not engage the fuel pump because it's the wrong one.

Shade it will start with a wrong ECU makes me think not the stator?

That's right , I forgot that detail.