[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-496329-105":59,"doc-detail-496329-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","driveability-corner-evaporative-system-leak-testing-tools-smoke-plume-and-small-leak-identification","Driveability Corner - Evaporative System Leak-Testing Tools, Smoke Plume, and Small Leak Identification","","Evaporative (EVAP) system leak detection can reliably find larger leaks using established leak-detection tools, but smaller leaks require more creative approaches. The document evaluates smoke-machine methods with precision orifices of multiple sizes, compares smoke visibility using controlled lighting, and uses a flow gauge to gauge relative leak magnitude, including practical limits near the gauge’s capability. For very small leaks, it recommends dead-calm conditions, pressure testing, and hydrocarbon or CO2 verification with a gas analyzer, including ultrasonic testing limitations.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/driveability-corner-evaporative-system-leak-testing-tools-smoke-plume-and-small-leak-identification/496329/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/driveability-corner-evaporative-system-leak-testing-tools-smoke-plume-and-small-leak-identification/496329.png","ImageObject",300,407,{"name":92,"@type":93},"BigDaveOnline","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-31","2026-10-02",true,{"@type":102,"interactionType":103,"userInteractionCount":19},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"How is smoke-machine flow gauge used to determine an EVAP leak size?","Question",{"text":112,"@type":113},"Use the smoke machine’s flow gauge to determine relative leak size, and rely on gauge scales rather than ball heights when viewing zoomed images. For more accurate low-flow results, use TEST mode instead of SMOKE mode.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"Why is a dead calm environment required when searching for very small EVAP leaks?",{"text":117,"@type":113},"The document states that smoke identification of small leaks requires no air circulation. Keep shop doors closed and turn off A/C and fans to eliminate drafts during testing.",{"name":119,"@type":110,"acceptedAnswer":120},"What should be used to detect very tiny leaks beyond the smoke method’s practical capability?",{"text":121,"@type":113},"Use a gas analyzer for hydrocarbon (HC) detection or carbon dioxide (CO2) if CO2 is used as the charge gas. Shop air is not safe as a charge gas, and the analyzer helps follow the HC plume to find the maximum concentration near the leak.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},496329,1792236252,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":19,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":81,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":143,"read_time":39,"preview_page_count":4},962090896214,"https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d","Driveability Corner   \nEvaporative system leak-detection tools and techniques for finding larger leaksarewellestablished. Asvehicleself-testingcapabilitiesget moresophisticated,you’llneedtobemorecreativetofindsmallerleaks.  \nI  \nwas wondering how much smoke machine smoke would escape from a .040-in. evaporative system leak. This would be useful to know for evap system testing. And how much smoke comes out of  \n.020- , .015- , .010- , .007- , .005- , .004- , .003- ,.002- and . 001-in. leaks? To find out, I ordered some precision orifices and proceeded with testing.  \nHaving had good success finding small evap leaks with a gas analyzer, we also tested the hydrocarbon (HC) plume with the orifices and a gas analyzer. We also tested the effectiveness of indentifying all leaks with the flow gauge on the smoke tester. Finally, we tested small leak location using an ultrasonic tester.  \nFig. 1 below shows our setup. The precision orifices have a 1⁄8-in. pipe thread, and we screwed them into a union held ina vise. The union was then connected to the smoke machine hose.  \nFig. 1 shows smoke coming out of a.040-in. (1mm) orifice. We had near per-  \nfect illumination, with two high-powered lights from two different angles. The smoke plume from this leak is about the size of a man’s forearm. The smoke plume from the . 020-in. ( . 5mm) orifice is about 2 in. wide and 15 in. long. These two leaks are pretty easy to locate with smoke. At.015 in. , things get a little trickier. The smoke plume out of an orifice this size isabout the size of two fingers, and difficult to see without perfect lighting.  \nOkay, let’s drop back for some review. You might want to reference my June 2009 evap-leak-testing article to complement this one. The first things we need to know are, do I have a leak now and, if so, how big is it? As I stated in that 2009 column, you use the flow gauge on the smoke machine to make this determination.  \nTake a look at Fig. 2 on page 18. There are a couple of important points to be made here. The images are zoomed in asthe leaks get smaller, so the relative heights of the balls in the image are not relevant; refer to the gauge scales instead.  \ncontinued on page 18  \nFig. 2 The smoke machine’s flow gauge can be used to determine the relative size of an evap system leak. Our tests with precision orifices revealed the practical limits of this technique.  \nGauge your knowledge and ease test jitters beforehand.  \nAvailable exclusively online  \nOne-half length  \nASE-style tests  \nIncludes performance reports and explains answers  \nAvailable for Auto exams A1–A8 plus Auto Parts P2  \nThe  \nOFFICIAL  \nPurchase Online [at www.ase.com](at www.ase.com)  \nASE... The Credential for Tough Times  \nPRACTICE TESTS  \nTaking ASE’s Computer-Based Tests this Summer? Info at  \n[www.ase.com/cbt](www.ase.com/cbt)  \n18  April 2010  \nDriveability Corner  \nAlso, when using the flow gauge for precision testing, it’s best to use the TEST mode and not the SMOKE mode (see the photo on page 16) . In SMOKE mode, the machine heats the smoke chamber and the ball tends to bounce quite a bit from the boiling action. In TEST mode, no smoke is being produced and the flow is much smoother, which affords more accurate low-flow testing.  \nAt .007 in. , the ball is darn near seated; this is at or near the limit of the flow gauge’s test capability. Remember, if you think the leak is intermittent, watch the flow gauge and wiggle-test the system.  \nThe most important point to be made is this: When looking for  \nMost smoke machines time out after five minutes, so keep an eye on it during testing.  \nsmall leaks, you must be in a dead calm environment! This means all shop doors closed and a/c and fans off—zero air circulation.  \nThe smoke machine’s flow gauge will identify if you have a leak down to a pretty small size. Smoke works great for .040- and .020-in. leaks. But how are you going to find the really tiny ones? Use a gas analyzer when looking for HCs or carbon dioxide (C","cbCaionIwGO71VH8","https://ap.wps.com/l/cbCaionIwGO71VH8","pdf",556500,"English","# EVAP system leak detection overview\n## Smoke machine and precision orifice testing\n## Flow gauge usage: TEST vs SMOKE mode\n## Detecting ultra-small leaks with gas analyzers\n## Practical setup details and final cautions","[{\"question\":\"How is smoke-machine flow gauge used to determine an EVAP leak size?\",\"answer\":\"Use the smoke machine’s flow gauge to determine relative leak size, and rely on gauge scales rather than ball heights when viewing zoomed images. For more accurate low-flow results, use TEST mode instead of SMOKE mode.\"},{\"question\":\"Why is a dead calm environment required when searching for very small EVAP leaks?\",\"answer\":\"The document states that smoke identification of small leaks requires no air circulation. Keep shop doors closed and turn off A/C and fans to eliminate drafts during testing.\"},{\"question\":\"What should be used to detect very tiny leaks beyond the smoke method’s practical capability?\",\"answer\":\"Use a gas analyzer for hydrocarbon (HC) detection or carbon dioxide (CO2) if CO2 is used as the charge gas. Shop air is not safe as a charge gas, and the analyzer helps follow the HC plume to find the maximum concentration near the leak.\"}]","Driveability Corner - Evaporative System Leak-Testing Tools, Smoke Plume, and Small Leak Identification | PDF",1790930902]