Chrysler never made a 4.3L, and Jeep engines aren't interference engines. GM has a 4.3L but that isn't an interference engine either. You shouldn't have had bent valves with a timing chain problem.
If you're getting spark you know the automatic shutdown (ASD) relay is turning on. That rules out a problem with the signals coming from the camshaft position sensor and crankshaft position sensor. 125 pounds of compression is acceptable but lower than normal. If you are not confident the camshaft timing is set right you might want to double-check that. That leaves fuel as the last suspect. Pressure alone can be misleading because the fuel pump will run for one second each time you turn on the ignition switch, but it won't continue to run during engine cranking if the ASD relay doesn't turn on. Since you have spark, we would assume the pump is running too. If the injectors are firing you should smell gas at the tail pipe. Any chance the gas is old and stale or contaminated with water? Draw a little out, throw it on the floor, and throw a lit match on it. If it puts the flame out, drain and refill the tank with fresh gas. We had two cars in a row with that problem. The mechanic wasted an entire day chasing the first one until he did the match trick.
Thursday, March 28th, 2013 AT 8:14 AM