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1990 4.0 My van was running fine going down the highway, then all of a sudden it backfired and stopped. Tried to start it again, it was backfiring and it wouldn't start. Tried again, seems the engine is spinning over faster than normal. It will start sometimes now but its still backfiring. Any suggestions would be appreciated.
Disconnect battery, pull #1 cylinder plug, locate TDC by using socket on front crankshaft nut to spin crank and see if #1 TDC and timing marks on crank pulley match up. A faster cranking by the starter and backfire is usually indicative of incorrect valve timing. Sounds ominous.
Have also had the problem where the pin that holds the gear on the bottom of the distributor was sheared. My 93 4.0 is all electronic so not sure about yours. So if you have a distributor cap, pull it & see if the rotor is rotating.
Me figured out what was wrong. It wasn't the timing chain or the crankshaft position sensor. It was the three little wires coming out of the harness where it connects to the sensor. They were wearing on something so bad that they wore right through and shorted out. Thanks for everyones help. I really appreciate it.