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Hey yall Im a new user, first time forum poster and Ive got a question. Ive got a 78 bronco with a 429 in it and it starts great when its cold, but drive it around for awhile, shut it off, and try to start it again and it has trouble turning the engine over. Ive put a new napa starter on it, new coil, new ignition box, new battery, and its still doing it. It acts as if the battery is dead when it gets hot, but leave it alone for the rest of the day and it will start up immediatly. Any ideas would be appreciated! Thanks!
Kenny
Slow crank can be caused by battery, starter, cables or timing. Make sure the cable connections are clean and tight. If there's any signs of corrosion in the cables, replace them and get as thick of cables as you can find. Check timing.
Is your alternator charging? Make sure you're not just running off battery. Not really sure this would be related (since it fires up good after sitting, sometimes a battery will get a little more juice after not having a pull on it for awhile), but seems you've gone over most of the other stuff. Assuming you've cleaned up your connections real good at the battery, silenoid and starter. You could also test your cables if you have a meter.
Yep, all the connections are tight and there is no corrosion on them. They're either 2 or 4 gauge wires I forget, but they're pretty thick. I havent checked the timing though, I need to get ahold of a light. Im getting 14 volts at the battery, so the alternator is charging.
Marty could you tell me a little more about how the timing being off could cause a slow start? Im curious.
I was thinking of making a heat shield for the starter in case it was getting hot and causing it not to want to turn. I appreciate the input, let me know if yall think up anymore possible causes! Thanks!
I would try backing the timing off a little, mark where it is now, then back it off some and see how it works. When it is too far advanced it will not want to turn over when warm.
Remove the negative batt cable from the block and wire brush the area of the block that the cable attaches to assure good ground and clean the end of the cable before you bolt it back on. For the timing, if the timing is way advanced and you have decent compression in the engine, the plug firing before the piston reaches the top of it's stroke works to push against the starter trying to crank the engine over. That results in slow cranking. The Duraspark ignition is actually supposed to retard the timing during starting if it is operating properly.
this may sound a bit left field to other ideas, but it worked, I had the same problem with a 351 Cleveland and got all the same answers from the so called experts including auto electricians... after chatting with a mates brother he suggested a starter relay, due to the starter and solenoid being so close to the manifold it can cause heat soak and volt drop, if I lived less than two inches from an exhaust manifold I won't want to work either, for a $7 relay it's well worth it, after installing I can drive around all day in excess of 35oC heat and she starts first time just as if she were cold, if you don't have a starter relay it's a very cheap investment...
Well I dont have headers but Im gonna try the heat shield anyway. I'll also check out the timing. Thats makes sense that it premature fire would cause more torque than the starter puts out. ALthough I did put the meter on it and it shows around 9 or 10 volts on the coil when its turning over, which means the box is functioning properly right?
Im not sure what year the motor is, it was in there when I got the truck.
As far as my starter solenoid/relay setup, its on the fenderwell. Do you mean add an extra relay in the circuit somwhere? Theres no relay near the starter right now. Thanks for the help guys!
Kenny
I had this problem. What I did was crank my engine to TDC and place the dist with the rotor facin the #1 cylinder plug wire, I had it backward so I had to turn it around one more time, but after that it started perfectly.
Make sure to check all engine to chassis ground. The ground cable from the firewall to the block on the passenger side of my 460 loosened and did the same thing.