Changing labels after swithiching between views - iphone

Question

I have two-views app for iPhone. On first one I call code that does this every second with NSTimer:
update variables
make sound
update label
update image position
When I start app - everything works perfect. When I go to other view and then go back to first screen - 1 and 2 works fine, but 3 and 4 resets and does not work at all.
What could be the problem?
Looks like it loses "hooks" to elements...
-(void)countup {
DeccelFloat += 0.4;
SpeedFloat += 5/(DeccelFloat);
SpeedInt = lroundf(SpeedFloat);
speed.text = [NSString stringWithFormat:#"%i", SpeedInt];
imageview.center = CGPointMake(imageview.center.x, imageview.center.y+3);
if (imageview.center.y < 280) {
imageview.alpha = 1;
if (SpeedFloat > MaxSpeedValue) {
[self playalarm];
}else{
[self playbeep];
}
}
if ((imageview.center.y >= 280) && (imageview.center.y < 283)) {
if (SpeedFloat > MaxSpeedValue) {
[self playshot];
}else{
[self playbeepbeep];
}
}
if ((imageview.center.y >= 280) && (imageview.center.y < 350)) {
imageview.alpha = 0.5-(0.5/70)*(imageview.center.y - 280);
}
if (imageview.center.y >= 350) {
imageview.alpha = 0;
imageview.center = CGPointMake(imageview.center.x, 180);
}
}
And here is my timer:
- (void)viewDidLoad
{
[super viewDidLoad];
MaxSpeedValue = 60;
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
NSNumber *maxspeedsetttings = nil;
NSNumber *blinkingsetttings = nil;
NSNumber *startedsetttings = nil;
if (standardUserDefaults) {
maxspeedsetttings = [standardUserDefaults objectForKey:#"maxspeedsetttings"];
blinkingsetttings = [standardUserDefaults objectForKey:#"blinkingsetttings"];
startedsetttings = [standardUserDefaults objectForKey:#"startedsetttings"];
}
MaxSpeedDef = [maxspeedsetttings intValue];
if (MaxSpeedDef == 1) {
maxspeed.text = [NSString stringWithFormat:#"%i", MaxSpeedValue];
}else{
maxspeed.alpha = 0;
maxspeedlabel.alpha = 0;
}
imageview.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:#"0.png"],
[UIImage imageNamed:#"5.png"],
[UIImage imageNamed:#"10.png"],
nil];
imageview.animationDuration = 1;
imageview.animationRepeatCount = 0;
BlinkingDef = [blinkingsetttings intValue];
if (BlinkingDef == 1) {
[imageview startAnimating];
}else{
[imageview stopAnimating];
}
[self.view addSubview:imageview];
StartedDef = [startedsetttings intValue];
if (StartedDef == 0) {
SpeedFloat = 0;
DeccelFloat = 0;
timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(countup) userInfo:nil repeats:YES];
StartedDef = 1;
if (standardUserDefaults) {
[standardUserDefaults setObject:[NSNumber numberWithInt:StartedDef] forKey:#"startedsetttings"];
[standardUserDefaults synchronize];
}
}
}