GPS receiver + Ublox NEO-6M - Having trouble making a timeout - arduino

Question

I'm trying to write some code that will turn on the gps module and wait for data to arrive, so that I can then do things with it. I don't need a continuous stream; I only need the first lat/long received from the gps unit, then I can turn it off. I also need this to just stop if it can't find it's location within a certain amount of time (20 seconds for example)
Here is some simple code that I've tried just to get the gps to read (full code with timeout comes later)
#include <TinyGPS++.h>
#include <SoftwareSerial.h>
TinyGPSPlus gps; // The TinyGPS++ object
SoftwareSerial ss(D4, D3); // The serial connection to the GPS
float latitude , longitude;
int count = 0;
void setup()
{
Serial.begin(9600);
ss.begin(9600);
Serial.println();
Serial.print("Starting");
}
void loop()
{
while (ss.available() > 0)
if (gps.encode(ss.read()))
{
if (gps.location.isValid())
{
latitude = gps.location.lat();
lat_str = String(latitude , 6);
longitude = gps.location.lng();
lng_str = String(longitude , 6);
}
}
Serial.println(lat_str + ":" + lng_str);
delay(100);
count += 1;
String Count = String(count);
Serial.println(Count);
}
When the delay above is 100, then everything works fine, when the delay is 1000, then suddenly no data comes through.
Here is the full code I've tried that includes my timeout and breakout condition, again not working. The cutoff line is in the GPS_mode function here: while ((stoploop < 1) && (previous - startTime < TimeOut)).
#include <SoftwareSerial.h>
#include <TinyGPS++.h>
TinyGPSPlus gps; // The TinyGPS++ object
SoftwareSerial ss(D4, D3); // The serial connection to the GPS d
int stoploop = 0; //used for stopping gps once a signal lock or timeout is reached
unsigned long startTime = millis(); // timer used for gps timeout
const int gpsCutoffPin = D1;
void setup() {
//initialise the serial monitor
Serial.begin(9600);
gps_ss.begin(9600);
//initialise the transistor pins
pinMode(gpsCutoffPin, OUTPUT);
// Start the gps in an off state
digitalWrite(gpsCutoffPin, LOW);
}
void loop() {
Serial.println("Enter GPS mode");
GPS_mode();
Serial.println("Back to the main loop now...");
Serial.println(stoploop);
delay(100000);
}
void GPS_mode(){
//turn on the gps
digitalWrite(gpsCutoffPin, HIGH);
stoploop = 0;
startTime = millis();
previous = millis();
int TimeOut = 60*1000;
gps_ss.listen();
Serial.println(stoploop);
while ((stoploop < 1) && (previous - startTime < TimeOut))
{
while (gps_ss.available() > 0)
{
if (gps.encode(gps_ss.read()))
{
logInfo();
}
yield();
}
}
gpsLat = (gps.location.lat(), DEC);
gpsLon = (gps.location.lng(), DEC);
// turn off the gps
digitalWrite(gpsCutoffPin, LOW);
}
void logInfo(){
// Causes us to wait until we have satelite fix
if(!gps.location.isValid())
{
Serial.println("Not a valid location. Waiting for satelite data.");
//return;
}
else {
//url += String(gps.location.lat(), DEC);
//url += String(gps.location.lng(), DEC);
Serial.println(gps.location.lat(), DEC);
Serial.println(gps.location.lng(), DEC);
stoploop = 2;
//delay(1000);
}
previous = millis();
}
I expect to see some gps data printed to the screen, but I actually don't see anything. I know that the gps is working and is receiving data because the blinking LED tell me so.
I have no idea how to fix this. If anyone could help I'd very much appreciate it.
Thanks