Hey, been wrestling with my truck and its stubborn start situation for a few weeks now. I've been searching through quite a few of other's posts of similar problems whist diagnosing my problem, but no luck. The truck body is that of the title, however my engine is a 351 COBRA JET.

Upon starting: Turn the key half click, let the fuel pump run. Lights, doorbuzzer and radio all work. Turn key full for crank and I get the initial slow "whurr..whurr" of it trying to turn over and the lights begin to dim as the continued cranking gets slower, so I let off the key.

Recently I've replaced my starter about a month ago, replaced the alternator in an attempt to fix the No-start, I know everybody jumps to the conclusion of a dead battery so I've had my old one tested(full charge) Had a friend look at it and said my battery cranking amps were too low(500 marine cranking amps). "Easy enough" so I get a new battery (750 CCA) clean points including putting a wire brush to the ground conneciton, try to start with high hopes, and no dice. The start situation is still as described above.

Got a hunch that I may end up buying/trying another new starter.

All expertise is appreciated.

 

Check all the connections, that includes the ground connection on the ground cable that bolts to the block.

You can also crank on it for a few seconds, and then run out and feel over all the large wires and their connections. If you feel anything that is hotter than anywhere else, that could be your problem. All your cranking power gets turned to heat in a bad connection.

If it's a slow whurr-whurr, then I would suspect a bad connection in the starting circuit, it could be a starter problem but it would be unusual to get two starters with the same problem. If the engine cranks with more of a fast-slow whomp-whomp, I would suspect the timing. You could disconnect the wires to the distributor and see if it cranks faster if you suspect this.

 

Yep...Dave went right were I was going to go on the timing. If it's advanced too much, you're tring to spark it too early in the compressoin stroke.

BTW...what's a 351 CJ?

And welcome to the forum

 

I had similar symptoms once, turned out the crankcase had filled with gasoline that had siphoned from the front tank.

There really isn't much to the starter circuit... battery + --> starter solenoid --> starter motor --> battery -. Hopefully your problem is here and isn't something like the engine being somewhat locked up.

 

Heavy, heavy sigh....

Let me google that for you

 

Yea about the losing power due to a possible corrosion in the larger wires(like the ones on the battery) seems to be a possibility. I have went out and touched the wires and they were a slight bit warmer than usual. but the starter relay was just as warm.

Is obviously safe to assume that if my belt moves, and the pulleys turn that the engine is not stuck/seized right?

 

That's Right!! There would be no turning over at all if it were seized up.

 

Sure, that's a safe assumption when considering an all-or-none scenario. But, consider an engine that is just prior to being 100% seized up. There were YouTube videos several years ago during the Cash For Clunkers thing when people were intentionally seizing up engines; some would seize up pretty quickly, others as I remember took up to half an hour.

It's just something to consider, hopefully your engine isn't at all seized up.

I would start with all of the primary electrical connections... battery to solenoid, solenoid to starter, engine block to battery negative. If you're using those clamp-on battery terminals, the kind that clamp onto stripped ends of battery cables, your problem could be there; water gets inside the cables and corrodes them inside. Starter solenoids can cause this behavior, too, as they burn/wear out.

When did this problem of slow-turning begin?

 

That's a very good point Chris. We are dealing with 25+ year old trucks here, and usually high mileage.

Just a thought but, have you checked to see if it cranks any better if you have a jumper battery hooked up?

 

well, the slow crank/turning began when it didn't want to start, about 3 weeks ago. It can be difficult to start if you don't pump the gas a few times, and always before it was like that, typical of a carbureted engine. The connections to the battery are the clamp ones, where you use a screw and nut to tighten them on, as I suspect most people use. I have yet to replace the battery cables but will do asap, for now I'm off to work my shift.