351 will not crank
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Joined: Oct 2005
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From: Lenoir, NC
351 will not crank
I have a 1989 F150 with a 351. It will not crank but it will turn over. It turns very slowly, not fast enough to crank. I checked the battery and I pulled the starter and had it checked. The starter was bad so I bought a new one and installed it. The motor still turns over very slowly. I drained the oil and replaced it. I found no metal shavings in the oil I drained but it did have some gasoline mixed in with it. I have poured some Marvel Mystery Oil thru the valve cover and I am letting it set over night before trying it again.
Anyone have any ideas? The motor might be bad. I just bought the truck and I do not have any idea of its history. I got it dirt cheap because it would not start.
Anyone have any ideas? The motor might be bad. I just bought the truck and I do not have any idea of its history. I got it dirt cheap because it would not start.
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Joined: Sep 1999
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From: Ventura, California
First back out the spark plugs and try to turn the engine over by hand with a breaker bar and socket on the center crank bolt. If you can turn it by hand, with the plugs out, the bottom end is not your problem.
What did you find when you 'checked the battery'? Is it fully charged? How are the battery post clamps, cables, and their end connections? All need to be clean and tight. If you see any green color in the strands in the cables, or any white fluffy looking deposits anywhere near the battery or cables, parts need to be replaced. White fluffy deposits at the battery posts mean the battery is damaged, and must be replaced. Make sure the cable going from the starter relay to the starter is in good shape, too, and make sure the starter relay is firmly mounted to the inner fender. It is grounded with the screws/bolts that mount it to the inner fenmder, so make sure the contact points are clean. Make sure the battery negative cable is in good shape, and is mounted tight and clean to the engine and frame.
What did you find when you 'checked the battery'? Is it fully charged? How are the battery post clamps, cables, and their end connections? All need to be clean and tight. If you see any green color in the strands in the cables, or any white fluffy looking deposits anywhere near the battery or cables, parts need to be replaced. White fluffy deposits at the battery posts mean the battery is damaged, and must be replaced. Make sure the cable going from the starter relay to the starter is in good shape, too, and make sure the starter relay is firmly mounted to the inner fender. It is grounded with the screws/bolts that mount it to the inner fenmder, so make sure the contact points are clean. Make sure the battery negative cable is in good shape, and is mounted tight and clean to the engine and frame.
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Joined: Oct 2005
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From: Lenoir, NC
Thanks for the advice. I had tried most of what you described for the battery. I think it was just tight from sitting too long because it fired up today when I tried it. I had put Marvel Mystery Oil in it and let it sit over night and it turns over fine now. It even ran for a mintue or so. I need to put some new gas and some fuel injector cleaner in it now but I feel sure the motor is not bad now.