hey guys i got a 79 f150 with a 460. whenever it gets warm it cranks really slow and sometimes wont start. i have tried to backoff the timing, and wrap the starter in a heat shield. also have replaced the starter and checked associated wiring. no headers just manifolds. any one got any other ideas????

 

Check battery condition, charge level also how old is the battery? Wires to the starter; from the battery to the solenoid and from the solenoid to the starter? How old and how clean and how tight are the connections?

 

the battery is new and i looked at all the cables and i dont see a problem with them. its sucking the life out of me i just want to drive the thing and cant rely on it to start. sometimes it starts good and others it wont hardly crank at all! i just dont get it

 

A new battery is not fully charged, ever. What kind of voltage is it reading when not in use? What is the voltage when you are cranking, both hot and cold. A new battery needs a slow charge of at least 12 hours, better yet 24 hours at under 2 amps. Have you replaced the sarter solenoid? How old are your cables and has any maintenance ever been done to them?

 

its reading around 12.25 volts cold or hot with the truck off. solonoid is about 1 year old and the cables are probably 10 years old but they look good. and everything is clean

 

You need to check the system & make sure your getting a full 12V down at the starter through the wire.
Lot of times, a wire might look good outside, but where it connects to the cable end it could be corroded & not making good connection & a full 12V not flowing through.

This test will take two people & you will need one of those big hand held battery testers like you see at service stations.

Take the battery cable end loose from the hot side of the battery, then go under & remove the main starter wire end loose from the starter, bend it away from anything metal it can come into contact with.
Now connect the battery cable back onto the hot post on the battery & then crawl under & connect the + side of the tester to the main starter wire & the ground side of the tester to the engine block.
Now, with that extra person, have them go try to start the engine & you watch the gauge on the tester & see if its a full 12V comming to the starter.
While that person is holding the switch to start, do the load test function on the battery tester & see what the gauge reads.
If theres a bad wire or bad connection somewhere, when you do the load test it will show a low or go to 0 reading on the gauge. The load test function on the tester is just like a dead short & will heat the coils inside the tester.
Thats kinda long & drawn out, but sometimes you got to go through the motions of putting your hands on something rather than guessing its this or that.
One thing about it, you do this test, put your hands on it, you'll never forget it & that problem wont ever stump you ever again.

My daddy was an old county hillbilly, didnt have nothing & most everything he needed he had to do hiself, so I learned some things from him, how to get by.
Neil

 

thank you very much i will give it a try

 

ok... another question. what about a ground from the firewall to the block?? i dont have one is it that important. could it affect starting??

 

The battery MUST be grounded to the block first and foremost. From the block to the body is necessary only if the battery is not grounded to the body. My 1993 PI Crown Victoria has two ground wire from the battery, one to the block and one to the fender and from the body to the hood and trunk lid and all the doors, but that is over kill because of all the radios that were in it.

 

i have two batteries and they are both grounded to the block. nothing to the body

 

You do need the ground from either the battery (preferred) to body or from the block to the body for proper electronics operations.

Are you using both batteries for starting or just one? If just one, does the problem occur with either battery or with both batteries?

 

it occures no matter what battery iam using or if i am using both.

 

That pretty much means the problem is either in the cables or the starter. Since you say you replaced the starter and it still does it, I would replace the cables and make sure the connections are all clean and tight and that includes the ground cable(s) and those connections too.

 

ok i will do that, thanks for all the help.