Problem with updating programmatically multi value field collection

Hello
I have a code to insert values in nodes of field collection which works no problem:

	function pdf_app_node_insert($node) {
			
			if($node->type == 'article') {
				$node_wrapper = entity_metadata_wrapper('node', $node);
				$pdf = $node_wrapper->field_pdf->value();
				$filex = file_load($node->field_pdf['und'][0]['fid']); 
  
                                $filenamess = $filex->filename;
 
                                $filenames = "/sites/default/files/pdf/".$filenamess;
				
				foreach ($node_wrapper->field_chapitres->value() as $library) {
					$library_wrapper = entity_metadata_wrapper('field_collection_item', $library);
					$ffp = $library_wrapper->field_from_page->value();
					$ftp = $library_wrapper->field_to_page->value();
					$fp = $library_wrapper->field_pdf_title->value();
					$password = $library_wrapper->field_pdf_password->value();
					$xx = "sites/default/files/pdf/".$filenamess;
					$pdff = concatenate_pdf($xx, 'split/',$ffp,$ftp);
					
					
					
                                        $pdfnews = upload_file_to_node($node, $pdff, $password);
					
					$library_wrapper->field_pdf_uploaded = $pdfnews;
					
					
					$library_wrapper->save();
					
					  $books = $library_wrapper->field_subchapters->value();
					  foreach($books as $book){
					    $book_wrapper = entity_metadata_wrapper('field_collection_item', $book);
					    
					    $title = $book_wrapper->field_pdf_title2->value();
					   
					    $ffp2 =$book_wrapper->field_from_page2->value();
					    $ftp2 = $book_wrapper->field_to_page2->value();
					    $password = $book_wrapper->field_pdf_password2->value();
					    $xx = "sites/default/files/pdf/".$filenamess;
					    $pdff2 = concatenate_pdf($xx, 'split/',$ffp2,$ftp2);
					    $pdfnews = upload_file_to_node($node, $pdff2, $password);
					$book_wrapper->field_pdf_uploaded2 = $pdfnews;

					$book_wrapper->save();
					   
					  }
				}
				
				 }
 }



				
					

the problem is that it is not working when updating nodes only when creating new nodes. I tried to add the same code with hook node update but there are errors. What could be done? I think there is a problem of memory of too many files opened.... when doing updating ... it does wrapper save too many times...