{"id":22493,"date":"2025-01-02T11:39:29","date_gmt":"2025-01-02T11:39:29","guid":{"rendered":"https:\/\/www.obd2tool.com\/blog\/?p=22493"},"modified":"2025-01-06T11:45:51","modified_gmt":"2025-01-06T11:45:51","slug":"detroit-ghg17-heavy-duty-mechanical-cylinder-compression-test-guide","status":"publish","type":"post","link":"https:\/\/www.obd2tool.com\/blog\/detroit-ghg17-heavy-duty-mechanical-cylinder-compression-test-guide\/","title":{"rendered":"Detroit GHG17 Heavy-Duty Mechanical Cylinder Compression Test Guide"},"content":{"rendered":"<p>This guide outlines the steps to perform a mechanical cylinder compression test on a Detroit DDC-SVC-MAN GHG17 heavy-duty engine. <strong>Note<\/strong>: This test should only be performed if directed by a diagnostic procedure.<\/p>\n<p><img loading=\"lazy\" class=\"alignnone size-full wp-image-22494\" src=\"https:\/\/www.obd2tool.com\/blog\/wp-content\/uploads\/2025\/01\/Detroit-GHG17-Heavy-Duty-Mechanical-Cylinder-Compression-Test-Guide.jpg\" alt=\"\" width=\"846\" height=\"610\" srcset=\"https:\/\/www.obd2tool.com\/blog\/wp-content\/uploads\/2025\/01\/Detroit-GHG17-Heavy-Duty-Mechanical-Cylinder-Compression-Test-Guide.jpg 846w, https:\/\/www.obd2tool.com\/blog\/wp-content\/uploads\/2025\/01\/Detroit-GHG17-Heavy-Duty-Mechanical-Cylinder-Compression-Test-Guide-300x216.jpg 300w, https:\/\/www.obd2tool.com\/blog\/wp-content\/uploads\/2025\/01\/Detroit-GHG17-Heavy-Duty-Mechanical-Cylinder-Compression-Test-Guide-768x554.jpg 768w\" sizes=\"(max-width: 846px) 100vw, 846px\" \/><\/p>\n<h3>Related Contents:<\/h3>\n<p><a href=\"https:\/\/www.obd2tool.com\/blog\/detroit-diesel-diagnostic-link-dddl-software-free-download\/\">2024.09 Detroit Diesel Diagnostic Link DDDL 8.20 8.09 Free Download<\/a><br \/>\n<a href=\"https:\/\/www.obd2tool.com\/goods-6833-JPRO+Professional+Diagnostic+Tool.html\">JPRO DLA+ 2.0 Adapter<\/a><br \/>\n<a href=\"https:\/\/www.obd2tool.com\/goods-10653-NEXIQ-3-USB-Link-Software-Diesel-Truck-Diagnostic-Tool.html\">NEXIQ USB 3 Link Adapter<\/a><\/p>\n<h4>Preliminary Considerations<\/h4>\n<p>Before performing this test, investigate the following possible causes of engine issues:<\/p>\n<ul>\n<li>Jake Brake\/piston damage<\/li>\n<li>Valve lash\/valve train damage<\/li>\n<li>Camshaft timing issues<\/li>\n<li>Cylinder liner\/ring damage<\/li>\n<li>Fuel injector hold-down failure<\/li>\n<li>Blown cylinder head gasket<\/li>\n<li>Cracked cylinder liner or head<\/li>\n<li>Valve or seat damage<\/li>\n<\/ul>\n<h4>Relative Cylinder Compression Test<\/h4>\n<p><strong>Important<\/strong>: Conduct a Relative Cylinder Compression Test using DiagnosticLink first. If results indicate a weak cylinder, proceed with the mechanical compression test as described below.<\/p>\n<h3>Mechanical Compression Test Procedure<\/h3>\n<ol>\n<li><strong>Check Valve Lash<\/strong><br \/>\nEnsure valve lash is within specifications before starting the test. Refer to the &#8220;Setting the Valve and Engine Brake Lash&#8221; section for instructions. Adjust as necessary. If no adjustment is needed, proceed to step 2.<\/li>\n<li><strong>Warm Up Engine<\/strong><br \/>\nRun the engine until the coolant temperature reaches normal operating range (88\u201396\u00b0C \/ 190\u2013205\u00b0F).<\/li>\n<li><strong>Disconnect Batteries<\/strong><br \/>\nDisconnect the batteries and connect them to a charger, following OEM procedures.<\/li>\n<li><strong>Remove Rocker Cover<\/strong><br \/>\nRefer to the &#8220;Removal of the Rocker Cover&#8221; section.<\/li>\n<li><strong>Remove Fuel Injector Harness<\/strong>\n<ul>\n<li>Remove the fuel injector harness.<\/li>\n<li>Disconnect electrical contacts from the fuel injectors.<\/li>\n<li>Disconnect the two wiring terminals on the Jake Brake\u00ae solenoids.<\/li>\n<li>Disconnect the 14-pin fuel injector harness connector.<\/li>\n<li>Remove the spring clip securing the injector harness connectors to the camshaft housing.<\/li>\n<li>Remove the fuel injector wiring harness(es).<\/li>\n<\/ul>\n<\/li>\n<li><strong>Remove High-Pressure Fuel Lines<\/strong><br \/>\nFollow the &#8220;Removal of the High-Pressure Fuel Injector Lines \u2013 Two-Filter System&#8221; section.<\/li>\n<li><strong>Remove Fuel Injectors<\/strong><br \/>\nRefer to the &#8220;Removal of the Fuel Injector \u2013 Two-Filter System&#8221; section.<\/li>\n<li><strong>Remove Residual Fuel<\/strong><br \/>\nUse a vacuum pump to remove excess fuel from the cylinders.<\/li>\n<li><strong>Install Compression Test Adapter<\/strong>\n<ul>\n<li>Install the compression test adapter (J-47411) into the injector bore in the cylinder head.<\/li>\n<li>Secure the injector hold-down clamp and bolt. Torque the bolt to 20 N\u00b7m (14 lb\u00b7ft) + 90 degrees.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Plug the Fuel Rail<\/strong><br \/>\nInstall the fuel rail plug (J-48704 or W470589129100).<\/li>\n<li><strong>Secure Jake Brake Solenoid<\/strong><br \/>\nInstall a hold-down bolt on the Jake Brake\u00ae solenoid and tighten it.<\/li>\n<li><strong>Reconnect Batteries<\/strong><br \/>\nReconnect the batteries while keeping the battery charger connected.<br \/>\n<strong>Note<\/strong>: Ensure battery voltage remains sufficient to maintain engine cranking speed, as low voltage can affect test accuracy.<\/li>\n<li><strong>Start the Mechanical Compression Test<\/strong><br \/>\nUsing DiagnosticLink, initiate the Mechanical Compression Test routine to disable fuel flow from the Quantity Control Valve.<\/li>\n<li><strong>Crank the Engine<\/strong>\n<ul>\n<li>With fully charged batteries, crank the engine over 5 compression strokes at a minimum of 150 RPM using the starter motor.<\/li>\n<li>Record the compression reading on the gauge.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Evaluate Compression Readings<\/strong>\n<ul>\n<li>At normal operating temperature, compression readings should be no less than 28 bar (400 psi).<\/li>\n<li>If readings are below specifications, repeat step 8 with a different gauge to confirm accuracy.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<p><strong>Note<\/strong>: Fuel injector hold-down bolts are single-use components and must be replaced after removal.<\/p>\n<ol start=\"16\">\n<li style=\"list-style-type: none;\">\n<ol start=\"16\">\n<li><strong>Reassemble Components<\/strong>\n<ul>\n<li>Remove the injector hold-down clamps and discard the hold-down bolts.<\/li>\n<li>Remove the compression test adapters.<\/li>\n<li>Reinstall fuel injectors and all removed components as per the relevant procedures.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<ol start=\"16\">\n<li><strong>Test Additional Cylinders<\/strong><br \/>\nRepeat the test for all suspect cylinders, following the same procedure.<\/li>\n<li><strong>Repair as Necessary<\/strong><br \/>\nAddress any identified issues according to engine repair guidelines.<\/li>\n<\/ol>\n<p>More repair cases for Detroit Diesel engines,please refer to:<a href=\"https:\/\/www.obd2tool.com\/blog\/category\/diesel-trouble-repair\/\">Detroit Diesel Engine Repair<\/a><\/p>\n<!-- AddThis Advanced Settings generic via filter on the_content --><!-- AddThis Share Buttons generic via filter on the_content -->","protected":false},"excerpt":{"rendered":"<p>This guide outlines the steps to perform a mechanical cylinder compression test on a Detroit DDC-SVC-MAN GHG17 heavy-duty engine. Note:<!-- AddThis Advanced Settings generic via filter on get_the_excerpt --><!-- AddThis Share Buttons generic via filter on get_the_excerpt --><\/p>\n","protected":false},"author":1,"featured_media":22494,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3469],"tags":[3009,3762],"views":1452,"_links":{"self":[{"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/posts\/22493"}],"collection":[{"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/comments?post=22493"}],"version-history":[{"count":1,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/posts\/22493\/revisions"}],"predecessor-version":[{"id":22495,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/posts\/22493\/revisions\/22495"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/media\/22494"}],"wp:attachment":[{"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/media?parent=22493"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/categories?post=22493"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/tags?post=22493"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}