Hi Lift problems

[nigeninja 0]

I brought a Hi lift with the Acoms Techniplus 4 fm and Tamiya 302 esc,I can run it for about 500 yards and then the fail safe on the esc comes on.So I thought this was a fault with the recivier or the transmitter,sent it back to the hobby company who tested it and it showed no fault.

The dude at the hobby co explained that the fail safe only comes on if there's lack of power in the battery,so to try it with one battery and take a new battery with you and when the fail safe comes on change the battery and see how long that works for.Well did that and the new battery worked for about a minute and the fail safe came on.Also when I came home I put the battery that had just failed on me in another car and it ran for ages so there was no fault with the battery.

I have also tried a 101 speed control in it and it did the same thing stop in the same place as b4(I know when it will pack up to about 10yards) so i can only think its a esc fault,unless anyone out there can help.cheers nige

[SGNAS 0]

Several possible reasons.

 

The receiver isn't getting a signal and cuts power - unlikely

There is too much friction in the driveline. Causing the motor to work hard, and overheat the esc(s). Could be why the lower rated 101fails quicker. See how well the car rolls or how hot the motor is when the esc cuts out. The  motor should not really get warm in 2nd gear.

The power drain on the BEC side of the receiver is large (running sttering and gear servos). Even with a partially charged battery the receiver can think the battery is too low and cut out. Check this by unpluging the gear servo and driving in 2nd only. Remedies for this are, runa seperate battery pack for the receiver or put a servo saver on the gear servo, it drains a lot of power keeping it hard up aganist the stops in 1st and 3rd.

 

In my opinion it is most likely to be a driveline problem.

[nigeninja 0]

So tighten up the slipper clutch nut on the front would cause overload on the motor,cos I did tighten it to one and half turns out rather than to two turns out.What do you think. 

[SGNAS 0]

have to eliminate the simple things first.

 

Run the car in 2nd with the gear servo disconnected. If it goes ok then the steering and gear servo are pulling more current thn the BEC in the ESC can supply. Then either your steering is stiff (check it) or the gear shift lever is too long (move the gearshift one hole closer to the centre of the servo or run it with a servo saver on the gearshift)

 

If it still cuts out then something in the drivetrain is binding.

Easiest to check is the axles. Undo the grubscrews on the propshafts and turn by hand. If stiff, pull the offending axle apart and rectify.

Next to check is the mesh between motor pinion and spur (slipper) gear, but unless you modified the cover, the gearshift servo will need to come out. If this mesh is too tight then the motor will overload, you'll probably not notice the sound over all the other gears turning. You can adjust it and run the car around in 2nd (the gearboxes natural position) without putting the gear servo back in to see if it still cuts out.

 If something is still stiff then it is gearbox out time. Not as big a pain as it seems. All you have to do is remove everything fore OR aft of the gearbox and then you can slide it along the rails. In fact on the threaded holes you do not have to totally remove the screws just undo them enougth that they are flush or below the inside of the rail.

[Dephcon5 2]

I have to agree with SGNAS. It sounds like too much load on the drive train and the esc is shutting down.

Just a thought, if you apply power from a single cell to the motor directly it should spin freely through all 3 gears with the wheels off the ground. If it does not then something is binding or causing lots of friction.

I tried this on my F350 after the initial build and the single cell only would spin the wheels in 1st. I thought something was not right as well because it didnt sound right either. After some digging I noticed the pin used to lock the diff on the rear backed out just enough to cause the rear axle to bind just enough to allow it to spin but with a heavier than normal load on the motor. Since that was fixed, everything worked great.

You'll probably find your problem is something similar. Hopefully you'll find it without having to tear the whole thing apart.

Good luck!

[nigeninja 0]

Thanks for your reply's I will go off and try what you suggest, cheers nige

[nigeninja 0]

Another big thanks to sgnas and Dephcon5 for pointing me in the right direction,guess what it was[:$]I do remember somthing on hear about the rubber plugs on the diff housing not fitting but me being me put them on cos they seem to fit ok to me[:$].

Yep it was the two rubber plugs binding on the diff lock pin,each plug has got a nice groove down the middle.So I took them out stuck a new battery in went up the field got to the 500 yard point and guess what it kept going and going and going and going in 1st 2nd 3rd and up and down hills,in short its fixed thanks agian chaps.

[mymonsterbeetleisbroken 17]

Glad its fixed,

although the manual doesnt clearly state it, the rubber bungs should only be used if your not going to use the silver diff covers. 

[defender experience 0]

How are you using your radio? I bought that radio and found it isnt compatible with the highlift?