Some guys have problems when using engine bolts as grounding points - it's better to go directly to the ground post on the battery - OR if you must use a bolt, like the one securing the fuel filter, be sure to completely remove the bolt and wire brush or otherwise remove the outer oxide covering the threads and underside of the bolt head - that coating resists current flow, potentially causing a poor ground and Comp operating problems. As suggested above, a good anti-oxide paste is a good precaution as well...