KWA M4 Not firing

[Denver Keith]

Had it for three weeks, gamed it once, posted it for sale today. Topped up the li-po and test-fired the M4. After a few short bursts, it quit firing. No motor noise, no response at all. Tried with multiple batteries, tested li-po on other AEGs to ensure it was OK. It's definitely the M4. Wiring looks fine.

Ideas?

[Skladfin]

fuse?

[T_A_N_K]

No motor noise at all? not even a click or a buzz? Take the motor out and see if it works outside the hand grip, however a broken motor can sometimes without load. I would just swapping out the motor, since you tested several batteries its probably a wiring problem.

[Shirley]

Happened to me, it could be just the wire connections.

[Skladfin]

fried the wiring or fuse for sure.

Check the fuse first, they use 15A which is pretty low for what you should be using with lipo, I sure as hell burned mine...

fring the wiring is unlikely though, they use 16GA wiring, and if the wiring were to burn out, the fuse would burn out first instead.

[Denver Keith]

Originally Posted by Skladfin

fried the wiring or fuse for sure.

Check the fuse first, they use 15A which is pretty low for what you should be using with lipo, I sure as hell burned mine...

fring the wiring is unlikely though, they use 16GA wiring, and if the wiring were to burn out, the fuse would burn out first instead.

Is the fuse cheap and easy to replace? If it's the motor like T_A_N_K suggests, I'm out of luck, since after the fiasco that was my first AEG 'project' I am hesitant these days to even take a peek at my gun's insides.

On another note, I had the same problem as a few people did in another thread, trying to hinge open the upper. Even after removing both pins, it only came out a little. I was applying enough pressure to break a plastic body when I gave up. Another lesson learned from my first AEG. Lol.

[Shirley]

The fuse is the far most cheapest thing you can buy and replace. You have to look inthe fuse if the connecter inside the glass tube is broken off. If so, you need to replace. Make sure you bring your old one so you know the size fits.

[BORDENSNIPER]

#1 check the fuse (of the little metal flat piece inside the galss is broken/burnt), also, make sure the battery is not dead.

#2 if fuse is fine, (take the motor off and press the trigger with battery in, to see if it works).

#3 if 1 and 2 are fine, then check the wiring therally (check connectors inside the little black fuse box, are they touching the fuse?).

#4 if nothing above works, take apart your gearbox, check if the connections inside the trigger swich are borken/rusted/too much oil/grease on them.

you should be fine, useualy with the KWA its the most obvious thing that screws up, jsut dont loose patience, work one by one and test every time to see if any change worked.

Also, a rare case, BUT, if nothing works, check to see the rails on the piston itself, it might have jammed inside the gearbox rails since u might have closed the upper reciever on top of the rails, making them crooked hence jamming them. (happened to me).

also, check to see if anything is out of place, stripped gears, broken etc... I doubt that will happen , but there is a chance.

dont use lipos, it might say lipo ready and may work with lipo but u will short the gears life dramasticalyl by using something that makes ur gun a minigun.

best of luck, dont loose patience, because when you do shit goes even more wrong.

[LyquidFyre]

As others have said, check the fuse first as a LiPo may very well have blown that sucker real nice. After that check for loose connections cuz if the motor isn't making a single noise, no buzz no humm...nothing that means it's not getting juice.

There was 1 report by another ASC User (Alex_20) where his KWA M4 stopped working due to a failure/break in the trigger mechanism. The details of the failure are unknown as is the fix but I figure it might be a place to look after you've eliminated any fuse or wiring issues.

Edit: Found the thread. Failure of the trigger's plastic components as Saint summarized.

http://www.airsoftcanada.com/showthread.php?t=60409

[The Saint]

Originally Posted by LyquidFyre

There was 1 report by another ASC User (Alex_20) where his KWA M4 stopped working due to a failure/break in the trigger mechanism. The details of the failure are unknown as is the fix but I figure it might be a place to look after you've eliminated any fuse or wiring issues.

Structural failure in the trigger unit's plastic components, leading to non-alignment of trigger contacts inside the mechbox. At least, that's what it sounded like by Alex's description.

[m102404]

Lots of good suggestions here...

I'll repeat some of them and add a couple of details:

1. Use a known good battery (7.4v large, 8.4v large, 9.6v large...shouldn't matter, any large battery should be able to pull that m120 spring)

2. If you get nothing (i.e. dead, silent, nothing pull), check your fuse. It'll be in the little (black in KWA's) platic tube/box. Automotive tube fuse, 15A or 20A. As a quick check you can put one semi-circular clip inside the other (i.e. jumping the fuse) and try it out with a regular battery (i.e. not a 11.1v lipo)...do not hold down the trigger...just a regular single shot pull.

2a. If you still get nothing, a quick check is to take the heat sink plate off of the grip and see if both motor connectors are on securely. The last two KWA's that I saw, they were quite loose. A gentle, minor squeeze with small pliers will stop them from coming off. Pull the motor out of the grip and hook the wires back up (red to red +, and black to the other). If you don't get anything from a trigger pull, either your motor is really dead, or the electrical system in the mechbox is dead, or there is a break in a wire somewhere.

2b. If, in 2a, the motor turns but when reinstalled will not turn over the mechbox...then your motor is weak/dead...or if you have installed an upgraded spring (which it doesn't sound like you have), the spring is too stiff for the motor/battery/gear-ratio.

3. If you get a "thunk" but no shot...try a burst of full auto. If you still get a "thunk", either your motor is too weak to pull that spring or your mechbox is locked up....either way, you'll have to start pulling things apart to find out. Now is the time to find a gun-doc.

Downside is that you might need some spare parts to find out what's not working...upside is that it's pretty easy to narrow down. Fixing it reliably is unclear at the moment, but a good gun doc will get you sorted out quick.

Hope that helps...

Tys

[dpvu]

If you have a multimeter you can easily do a quick continuity test on the wires to see if the wires, fuse and trigger assembly are all working. The advantage to this is you might even be able to find the problem without opening the mechbox.

Remove the motor and take the 2 probes and connect them to each end of the black wire. The black wire runs straight through so there should be continuity without you doing anything. Now do the same thing with the red wire except you have to pull the trigger. If there's continuity through both wires the problem is your battery or dead motor. If there's continuity on the black but not red, check the fuse (you can repeat the test and put the probe after the fuse to check) or it's a problem with the trigger switch assembly or wiring. If there's no continuity on the black wire, it's likely that wire is dead and needs to be replaced.

[m102404]

D'oh...keep forgetting to mention the quick multimeter check for the motor tests...

[Denver Keith]

Right, thanks for all the tips. However, there is still the issue of my utter lack of confidence opening the gearbox. So apart from checking the fuse, (which I just did as I right this...)

UPDATE: Yes, fuse is split down the middle and nicely roasted. Will replace and report when it's working. Will also reduce price to compensate.

[Skladfin]

ya okay. I know for sure what's happening after you said that you couldnt open the gun.

The problem is when you use Lipo with the KWA, even if you shoot semi auto, the piston is compressed after the shot is fired.

So the piston is stuck in the back of the mechbox where you can take a peek into the spring and spring guide. If you try to open the upper receiver, the tabs can't go up because the PISTON IS BLOCKING THE WAY. Therefore you can't open the gun.

furthermore if you try to shoot your gun at this same time, since you are applying pressure upwards with the upper receiver to the piston, the piston can't move forward, but you keep pressing on the trigger so you burn out the fuse.

happened to me.

so its the fuse, fuse is like... 50cents at canadian tire haha

open ur handguard, and you should see a black cylinderish thing connected to the wiring, open that and the fuse is inside there. If the metal in the middle is missing(not connected), then the fuse is blown. Or if you see a brownish residue inside the fuse, its also blown