I dont understand what it means by...

needle thread tension worng
no thread in the bobbin
neeld /hook timing is wrong

Is it actually the bobbin thread that loops or is the loop appearing on the underside of the fabric as you stitch? If it is a loop under the fabric, that's usually an indication it is an upper thread issue. Thread irregularities that appear on the topside of the fabric are generally bobbin related.

First thing to try is installing a brand new needle. Verify it is the correct needle for the fabric and thread being used.
All About Needles
Sometimes, the fabric being stitched will "grab" the thread and hold it for a second before releasing and will cause a loop. In this case, a needle with a larger scarf and eye may be helpful.

You might also open the upper tension as much as possible, RAISE the presser foot and run a piece of UNwaxed dental floss through the tension disk a few times to clear out any gunk that may be stuck there. A piece of pearl cotton dipped in rubbing alcohol and squeezed moist/dry will also work.

Remove the upper thread. RAISE the presser foot and rethread the top thread from the beginning. Use only fresh, good quality thread--NO old or bargain bin variety! Try using the same thread in the top and bobbin. Make sure the thread is firmly seated in the tension disk and the thread path is correct. Check that there are no burrs or snags in the thread path that could be catching the upper thread. Especially, check that the thread is not catching on the spool "slit" that holds the thread when in storage. Every time the thread navigates around the thread spool, it could be catching on that slit just enough to cause a loop.

Try changing the bobbin. There could be something amiss with the current bobbin--could be nicked or could even be the wrong bobbin for the machine. Also, make sure the bobbin is loaded and turning the correct direction in the machine.

Set the upper tension to the midway point. This is usually the starting point, although it will probably require some tweaking. Test your stitch and adjust the tension so the upper and bobbin threads meet in the middle of the fabric. Neither thread should dominate one side of the fabric or the other.

Understanding Thread Tension Threads

Last thing to try is a different presser foot.

If you still have the intermittent loop, you might want to take it for service. Could be a problem within the tension disk.

If your machine is functioning properly, when the needle goes down into the bobbin area, the needle thread will catch the bobbin thread in a loop. (If you gently pull the upper thread tail, you will be able to pull the bobbin loop up above the needle plate.) If your machine is not doing that, then there is something wrong. Make sure the needle is installed correctly and both threads are threaded properly.

How and Why to Bring up the Bobbin Thread

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Hi Jennifer:

Do you understand how a stitch is formed on a sewing machine? The needle goes down to its full down position. At that point the shuttle hook should be pointing right at the needle scarf, ready to go past it as the needle starts to go up.

When the needle starts its upward travel it forms a loop... the shuttle hook enters the loop and the bobbin thread is "captured" in that loop.

If your machine's timing is advanced, the needle will hit the hook and break or make nasty thumping noises. If your timing is ********.... the hook misses the loop entirely and does nothing.

So... open up the entire bobbin/throat plate area.... take the foot off so you can see. Clean if necessary. Then turn the hand wheel by hand until you see that the needle is at the lowest point of travel. Where is the shuttle hook?

From there you'll have to use your logic to find the right screws and adjust the hook.

Here' is a Parts Chart for your machine.
http://www.parts.singerco.com/IPpartCharts/404-1_4_5.pdf

Good luck!

1. Either the needle is smaller than required and does not reach down enough to loop the bobbin thread.2. Or the bobbin thread is not kept out of the shuttle and does not make a loop with the needle thread.

The foot is on the side. Make sure it is clean. Take off the plate and remove the bobbin cleaning all the lint and thread out with q-tips. Oil if needed. Make sure you are using the same thread in the bobbin as on top. Rethread the machine making sure you do it correctly. Change needles using Schmetz as it is shorter and I have found Singer and white label needles are too long and cause problems and well as break easily as they hit the bobbin and cause looping. Not sure what you need to know about the foot. It should have a handle on it so you can put it up or down. Google Brother model XL 2230 and download a manual to find lots of info about your machine.

Make sure the thread is coming off the bobbin counter-clockwise, hold the end of the thread in your left hand, drop the bobbin into the case, and pull the thread into the slot at the front of the bobbin case by pulling it up and around the bobbin case to the left until you hear a click. That means the thread is in the bobbin tension. Then hold the needle thread in your left hand but don't pull on it; drop the needle into the machine and bring it back up by hand with the balance wheel, and as it comes back up, gently pull on the needle thread. That brings the bobbin thread up through the throat plate in a loop so you can pull it on out, and you're ready to go.

You only need the thread to loop over the bobbin thread to bring up the thread when you are threading the machine. If, you mean it is not sewing after threading then I need more information.

Hi there,

Well you may please follow the steps below -
1. Remove the bobbin from the sewing machine. Note: whether you have a drop-in, front or side-loading bobbin on your sewing machine. A drop in bobbin will load from the top, may be via a removable bobbin case cover near the machine-fed dogs. A side or front loading bobbin needs to be loaded into a removable bobbin case under the machine.
2. Choose the right size bobbin for the sewing machine.
3. Wind thread onto your bobbin. Your sewing machine should have a standard thread spool to hold the thread and a short, squat post wide enough for a bobbin.
4. Put the thread and empty bobbin into position on your sewing machine. Wrap the thread around the bobbin to start it. On most machines, disengage the needle by turning the smaller hand-wheel on the machine toward you. Push the bobbin post into position, securing the bobbin into place. Press gently down. Thread should begin to wind neatly onto your bobbin.
5. Break the thread, push the bobbin post back into an inactive position and remove the bobbin. Tighten the hand-wheel. Thread your sewing machine again if necessary before loading the bobbin.
6. Remove the bobbin case cover and put the bobbin into position. The thread should slide through a catch on the bobbin case and up through the cover.
7. Access the bobbin case for a front or side mount bobbin. Lift the catch and remove the removable bobbin holder. Put the bobbin into the holder and run the thread through the holder, bringing it to the front. Lift the catch and slide the bobbin holder back into the case. Hold your needle thread gently forward with your left hand and turn the hand-wheel. The needle thread will pass down into the machine and catch a loop of the bobbin thread. Pull this loop up and slide both threads to the back before beginning to sew.
Good Luck!!

Thanks for using FixYa!!

Hold the tail of the needle thread loosely.  
Turn the hand wheel toward you (counter clockwise) and lowerthe needle into the hole in the plate. 
Turn the hand wheel until the needle rises back up to it's highest position.
Gen
You will see a loop of thread wrapped around the upper thread. 
Open the loop and find the free end of the bobbin thread.  
Voila!
Now you can sew.