TM M4A1 firing problems

[BlackRain]

Okay here goes, TM M4A1 does not fire consistently, on semi it fires a few rounds then nothing... doesn't seem to cycle fully...then it fires fine, also sometimes just rolls BBs out of the barrel. Switch to FA and the same thing happens, it almost seems like there is not enough power. A few times it fired 3 BBs out at the same time. Battery was fully charged and is a 2300ma so there is plenty of power in it. Trigger also seems to bind every now and then as well... a new systema selector plate was also installed. Any direction or help on what I need to do to fix the issue would be greatly appreciated. I did read an article that said a new systema trigger low resistance high capacity assembly should be installed when a systema selector plate has been installed. Any truth to that?

[Styrak]

Perhaps the nozzle is not attached to the tappet plate, or the tappet plate spring is not where it should be, causing misfeeds and poor airseal.

[screwdriver]

firstly try another battery, i found the same problems when i switched to using nimh from nicad.
the batteries gave no warning of going flat and i was convinced the gun was jamming.
i also have the tm m4a1 and occasionally it jams on semi, this is due to inconsistant trigger pulls ,releasing the trigger before cycle complete.
this can cause the semi auto lever in the gearbox to settle in the wrong position after a shot and either jam the trigger or open circuit the trigger switch stopping the gun from working, a quick full auto burst will cure this.
but as above i find nimh cells unlike nicad dont slow down they just go flat, and if the tappet nozzle is in the correct position pulling the trigger can rock the gearbox between the anti reversal latch positions causing it to multifeed bb,s but not fire as to flat

[m102404]

It's tough to guess on this one without seeing it...

Sounds like the trigger isn't pushing the switch block far enough into the switch assembly every time.

1. Check that the wiring below/around the trigger is laid flat and nice so it's not binding it up.

2. Check that the trigger top isn't all worn and rounded...or else it'll slip on the switch block

3. Maybe squeezing the two metal fins in the switch assembly just a little bit closer would sort you out.

Best of luck,

Tys

[Gunny_McSmith]

I had the some problem on my Src Hk416... And i first thought it was the tappet plate, but it was a misalignment of the hopup unit, so the bbs where stuck in the chamber, and after 3 misfeeded rounds they would all burst out of the barrel...
You should try that before going into the gearbox...

[CDN_Stalker]

I'd likely start by focusing on the hop up unit and the hop up rubber. Sounds like the rubber is torn and sticky, causing BBs to plug up inside (yet loading) and then spits them out, but because of torn rubber, serious airleak.

[BeAcH]

sounds like the tappet plate is not being hit/pulled on every cycle rotation, if you installed the selector plate did you put all the shims back in the proper place. One missing shim is all it takes for your tappet plate to not engage fully on each gear cycle rotation...

[BlackRain]

Thanks for all the replies, looks like I will start with the hop up unit and move onward from there to inspect the rest. The new plate was installed by the previous owner before he shipped it out to me. I may make a short video demonstrating the problem and see what you all think.

[BlackRain]

Ok.. now I am stumped... took the mech box apart and checked everything... put it all back together and now the damn thing doesn't shoot at all.. seems like no power getting to it. Can't hear any noise whatsoever. Any suggestions?

[The Saint]

What's the condition of the wires? Any binds, twists or potential breaks anywhere?

[BlackRain]

Wires from the switch assembly look like ass to be honest... multiple splices... also just broke one of the wires so I now have some soldering that needs to be done.. I am going to take the wires back to a clean untouched area and run a new splice correctly to the deans connector I installed. Who ever made the wiring for what ever was installed in this gun needs to learn to use proper color codes... every damn wire in the thing is blue... what a pain in the ass.

[Muffin]

It may be worth your while you get a completely new wiring harness, no soldering needed.

[BlackRain]

Seems to be just the wires to the rear stock that are shot... the rest look to be in good condition. Who ever did the wiring originally was miss matching the trigger switch wires to the battery. The splice that was put in was with a smaller gauge wire then the original. So I am going to replace it with the same gauge wire.

[charles_tk]

better check on the wiring or better yet the switch assembly. have you checked the fuse? fif you dont mind whats your set up inside your gearbox?

[BlackRain]

Well this is my first AEG so I am not so familiar with everything yet...lol. The bevel gear has a CA stamp on it and the sector gear has a G&P stamp on it and the spur gear is unmarked so I don't know the make. All the bushings are metal and the spring seems to be an aftermarket of unknown type, the color is blue. The trigger switch is the one for the rear battery placement and is red in color beyond that I don't know much else about it other than its running a stock motor TM 700.