I have a 2001 focus. One day it wouldn't start. Worked to jump start but then when I turned it off I would have to jump it again. Replaced battery. It worked for a while then dead again. Repllced alternator now it cranks but will not turn over. The shop I have it at ran diagnostics for 4 hours and can not find a problem. Any ideas? I am puzzled.

 

If you fixed your original no-crank problem and now it won't fire, maybe all you did is flood it. Can you give more details on what it did and what it is doing?

 

I'm not a mechanic but I fiddle. When you jump start it and let it run a while, then shut it off and it won't start again unless you jump it again the first 2 thoughts are alternator or battery. This is common issues. Easiest way to check which one is run a multimeter across the terminals and make sure you have about 14 volts with the engine running. If you do the alternator is good. Shut off the motor and check again. Should show about 12 for the battery. Check again after about an hour. If it is going down it's usually the battery. Always clean the terminals first. Sometimes they don't get enough connection to start the motor (starting is the largest drain on the battery).

Since your issue is not starting check the above. Could use some more info though.
Does it seem to crank slow? If yes, does the inside lights dim when trying to crank?
Does it crank normal speed but doesn't get any kick from a power stroke?
Does it get a kick every once in a while from a power stroke?

Did it no longer start prior to the new alternator? Did the alternator fix it and then it stopped working again? Does it still start if you jump it?

 

Just in case you didn't see it, the poster said he replaced both.

AND, the shop would have really been incompetent to not figure out a battery or alternator.

In light of the shops inability to find in 4 hours, it's probably doubtful about my flooding theory also.

 

HI THERE IM NEW TO ALL THIS SO HERE GOES I WAS JUST READING THIS POST AS I HAVE THE SAME FAULT ON MY 98 S PLATE FOCUS THING IS I DO KNOW ABOUT CARS A LITTLE BUT THIS REALLY HAS STUMPED ME AS I HAVE CHANGED THE STARTER MOTOR THE ALTERNATOR AND THE BATTERY YET IT STILL WONT TURN OVER BUT WILL BUMP FINE AND IF I PUT THE BOOST PACK ON IT STARTS OK THE NEW PARTS ARE ALL OEM PARTS AND FITTED CORRECTLY AND SECURELY THE ALTERNATOR IS FROM A ST 170 AS ITS BIGGER AND MORE POWERFULL THAN THE ORIGINAL 1.8 ONE ALSO THIS STILL HAPPENED BEFOR I CHANGED IT AND AFTER SO ANYWAY I CHANGED THE STARTER MOTOR STILL NOTHING BUT YET STILL FIRES WITH THE BOOST PACK I HAVE CHECKED ALL THE EARTH CABLES ,BATTERY CONNECTIONS,FUSESAMPS GOING IN TO THE BATTERY EVERYTHING SEEMS FINE WHEN RUNNING BUT JUST WONT START ON THE KEY IT ATTEMPTS TO BUT THEN NOTHING (about 2 or 3 turns very very slowly)CHECK THE BATTERY AND YEP THE POWERS DROPPED BUT EVEN AFTER CHARGING IT TO FULL POWER THE IT WILL START ABOUT 5 TIMES IN A ROW THEN BACK TO THE SAME THING AND EVEN IF I CHARGE IT THEN PUT IT ON AND START IT ONCE AND DRIVE IT I MIGHT BE LUCKY AND IT WILL START AGAIN WHEN I GET BACK AFTER ABOUT 45 MIN CONSTANT DRIVING OR IT MIGHT NOT DEPENDS HOW IT FEELS I SPOSE LOL BUT HONESTLY THIS HAS BEEN GOING ON FOR ABOUT 18 MONTHS NOW AND I REALLY AM FED UP WITH BUMPING IT OR JUMPING IT LOL PLEASE HELP PLEASE PLEASE PLEASE

 

Flywheel bind? Hydrolock? Eratic ignition switch or solenoid/relay ??? What happens to headlights when it does not want to go? Do they dim way down as if theere is a big power draw? Compare to when it DOES spin over.

 

hi again yeah the headlights dip to nothing as does the rest of the lights ie interior light dash lights ect.

 

If the lights dim when trying to start, sounds as if the battery is low or has a dead cell. A battery can have 12 volts but NO CRANKING AMPS! That is what you need to start not volts. If either you or hot911disp have changed the battery(you both have) and it won't crank(presuming it cranked well before this all started), I would look at the cables and/or connections. If it jumps and starts, you have a cranking amp problem.(maybe caused by the cables/connections, etc.) If hot911 replaced the alt. and it won't crank(turn over) then something is not connected properly or you forgot to hook up something. If you changed the battery, it worked for a while and now won't crank, you may have a drain on the battery running it down. I am presuming that the batteries that were changed were NEW and not OLD batteries from another car!

 

my battery is a new exide heavyduty diesel battery also mine was running fine no problems but did now and again fail to start but has now stopped cranking over like it used to and i have changed all three major components still nothing i have a inicator window on my battery that is green and i have tapped it to make sure its not jammed its fine i have also checked the cables they are fine as the red positive cable is a link cable direct from the battery to the starter motor then on to the alternator and its a all in one cable not cut or repaired i have even used a jump cable and created a more secure earth connection just incase it was a bad earth still nothing but if i put the boost pack on hey presto it starts (wierd)?

 

Oh. And have you put a volt meter across the battery terminals before you start it? And then see what the voltage is while it is idling? And while running, pull out lights, turn on radio and turn on blower motor and see what it reads? And after it has run for a while, shut off key and then take another reading and compare it to the very first reading I spoke of?