I bought an rc8 that came with a radio and electronics and was using it and the buggy went out of control for no reason while I was using it. The batteries were fresh in both radio and reciver. I tried making sure everything was snug put new batts everything seemed ok till I fired up the engine and gave it a rev and it went wide open (while I was still holding it). The throtle servo was going crazy while the the engine was running. So I bought a new 2.4ghz radio, reciver and a new throtle servo and gave it a test. Everthing seemed ok, I fired it up gave it a rev it seemed ok. I ran it in a few circles around me then decided to drive it down the alley. Once it got around 100'+ or so away it had no response and was wide open and crashed back and forth on each alley wall before flipping. So I replaced the batteries in the car, reciver is new, new radio, throttle servo what is going on here? I am so confused and frustrated, I have broken $100 dollars in parts it two crashes. Any ideas please throw them out there.

Something interfere. Does the alley you talking has electric poles (not the small the ones, the BIG ONES (66,000 V))? Try to run somewhere else.Also, do that to be sure: DON'T start the engine. Get yoyur car and get far away from it at about 100+ metres as you did. You will need a friend of yours. Tell him to check out the electronics. You will have in your hands the remote controll. Ask him if all is ok. If yes, then, get away your car about 10 metres more. Then test it again. I repeat not to start the engine!!! If the car is working fine after this test, then the problem is somewhere else, that i don't want to "deep" it

Another thing is to properly set your failsafe mode. On my spektrum stuff, you have to hold the brake when binding the rx to the tx. That will cause the car to hit the brakes when it loses signal.

However, Im willing to bet you have a loose connection the battery. That is usually the cause for a runaway with 2.4ghz. I've seen it many times. The connection may seem snug but it may have dirt in there or the wire has a loose connection elsewhere

Yeah, also sometimes, batteries (those which are 4 AA) which are tight and you think that will never the power be cut off, they cut off. I suggest a battery pack (those which are rechargeable). I had that problem with the loose batteries and my buggy went...far, and FORTUNATELY it hit a bush, thank God, no victims or broken parts

Thats a great idea about the batteries, I am going to get a rechargable pack today. I also am going to look into the fail safe mode and get that going and see if that helps. The buggy did do this before at my friends house that has the big power lines too, maybe that has something to do with it?

What radio and servos are you running?

I have an airtronics mx-3fhss. I have a new hytech servo for the throttle and a team associated servo for steering that came with the buggy. I just finished setting up the fail safe mode and noticed when I move the steering back and forth the throttle servo glitches back and forth. It only does it when I move the steering back and forth fast. I am not sure what is going on here. The radio seems to work fine close but fare away, not so much.

Anyone?

There's the proble,m right there, what's the model number?

It is the hs 645mg. What is wrong with the servo?

Nothing systemicly wrong with hi-tech servos, I'm using like 6 of them right now with no isses & at least 2 of them are 645MG's. Besides from your account of the events so far you changed the throttle servo already & both glitched. That means it is NOT the throttle servo that is the issue. Did you change the switch when you changed your radio??. Never ever run those 4 AA batter holders for your RX pack they always have issues. Get a good 5 cell rechageable pack. As mentioned above check all the battery wires for damage or loosness (this includes switch wires). You have already changed the TX, the RX & the trottle servo so it is VERY VERY unlikly to be one of those that is causeing your problem. That leaves the batteries(includes the holder & wires), the switch (& it's wires), and lastly but less likely the steering servo. It would be RARE for the steering servo to cause the throttle servo to glitch but it is possible & I have seen it. I once had a steering servo that seemed to work fine but I found that when I worked the steering the RX voltage would drop too low & the throttle whould go wacky. That would be the last thing to check in your case. For you first I would replace the rx battery pack & check the switch (& wires).

Three things to do, as stated above rechargable battery pack, pad your radio box so your receiver and battery don't slop around during runs. A fail safe is great but in a total loss of power a throttle return spring is your lifesaver. If you lose power to your receiver a fail safe doesn't work it is meant for loss of signal.

I did replace the battery switch with the new one that came with the reciver. I am going to go to the hobby shop now and see if they have any of the parts in stock to get the front end to put it back together. I also am going to pick up a throttle return spring, and rechargable 5 cell and new switch. Thanks for all the help guys, I am feeling more confident that this problem will be over soon, I am very new to this site and its already helped so much.

Digital radio with analogue servos, not a good idea.

That's never been an issue for me, in fact I avoid digital servos because they consume more power. I agree that a nice high quality digital servo will out perform many(most) analog ones but for offroad & my level of racing(local clubs), I never found an advantage in using them. They normally cost more, some brands have reliability issues & they all run down your RX pack faster.

Bagged, I missed that you had replaced the switch, so that's probably not your issue. Given the stuff you have replaced, the battery is your most likely bet. Also hrdcoreglf gave you some good tips as well. I always keep old scraps of foam around to jam into my radio box to keep stuff in place.

Ok, I went to the hobby store yesterday and bought a trinity 5 cell 1500 reciver pack. I got a new switch so I can charge it too. I bought the pads to keep everything tight in the radio box. I let the battery charge about 20 hrs and plugged everthing back in. It is still doing the same thing. When I turn the steering back and forth and hit the throttle servo the throttle servo is acting up. I move the steering back and forth while hitting the throttle servo and the throttle servo opens a little but not much untill I slow down moving the steering and it operates fine. It acts like the batterys are dead but they are fully charged. It seems to get some sort of radio interfirence. If I move the steering back and forth without touching the throttle, the throttle servo starts acting up (glitches and moves back and forth)

I think I will change the steering servo next, I have replaced everything I can think of so far. New 2.4ghz airtronics radio, new reciver, new rechargable reciver pack, new hytec throttle servo, new battery switch. I have never had a problem like this before.

Try them one servo at a time, just unplug one, try the throttle and steering controls at the same time and see what happens, probably nothingas the current draw wont be so high, now if you have or can get hold of a spare digital servo, slave that in place of the hitech one and then see what happens.

I am going to take it to the hobby store and see if I can use a digital servo and see if that makes any diffrence.