I found multiple problems with this unit due to the harness. These harnesses are made with small wires and tight bends. I changed the one under the dash and the engine harness. If you are smelling propane then I would suspect the vaporizer. The pressures are supposed to be 4.5 to 5.0 PSI the plug on top is your test port these are not rebuildable. If you do change the harnesses you have a small on going to your cam and crank sensors as well. Also look a the load injector it's the small one next to the main injector. They have a plunger on them that stick from the gunk. Hope this helps.