Hi everyone Im new to the board and I have a problem that I hope someone can help me with. I have a 1978 f-100 well I fried the fusible link because the last person who owned the truck had the red wire as the ground and the black wire as the positive. Well I fixed the fusible link and put the battery back in and nothing worked. I jumped the battery off and the lights came on but the starter wouldn't turn the relay just clicked. As soon as I took the cables off everthing went back to not working again. So I figured I killed some cells in the battery.So this morining I took the battery out of my chevrolet prism and put it in the truck. Well now all the lights come on the starter turns the engine but the engine wont start up.

Can somebody please help me out here,could it be that even though the chevy prism battery turns the enigine it isn't supplying enough power.

the chevy battery is smaller than the battery that was originally in the truck also it was really cold this morning and I noticed that the chevy prism's battery list 506 cranking amps and 405 cold cranking while the old battery list 731 cranking amps and 585 cold cranking amps.
Hopefully this will help .



thanks in advance.

 

By connecting the battery backwards you may have fried the alternator and the ignition modules. Take the modules and alternator to a parts store for testing.

 

The battery shouldn't be a problem. My buddy gave me a free battery that is around 500 cca and it turns my 302 over in even the coldest weather.

Erik

 

check for power at the coil check the resisance in the coil and put a new module in it

 

put a new module in the coil?

 

The module is the 4" square aluminum box on the drivers fender well with wires coming out of it. Remove it and take it to a parts store to have it tested - most will do this for free.

Let us know what you find.

Marty

 

oh he is talking about the ignition module ok I thought he was saying a module in the coil.Thanks I will get it tested and tell you guys whats going on.

 

The module is on the driver's fender on a 78, but is also a ignition module box (I can't remember what this is called) on the passenger fender that attaches to the solenoid. I have had this go bad and cause the engine not to fire.

 

can you give me a description of the ignition module box on the passenger side

 

I believe he's refering to the regulator. It's a small square box with a flat 4 wire plug, it mounts next to the solenoid or between the battery and the radiator - depending on the year of the pickup. The regulator tells the alternator how much to charge. It's likely this was damaged when the batt cables were crossed, a new one is $10-$15.

Marty

 

The voltage regulator can go bad. I had the local rebuild shop check mine. The replacement was like 10 bucks. The problem I had was that it stopped charging. If I had to guess, I would say voltage regulator, because it is the closest to the battery and would have recieved the most amps. Also, It would be the first link in the chain, so to speak. It could be as simple as a ground wire to your ignition system got fried. Check your wires for continuity before going through all of the trouble of testing ignition module and voltage regulator.

Erik

 

Yes, voltage regulator is what I was referring to. I could not remember that name for some reason.

 

Ok I thought thats what you were talking about the regulator.

One question could it be that the regulator is not grounded properly because I removed it aswell and it only had one bolt in it but I know it's supposed to have two in it, also when I put it back on the unbloted side hangs from the fender a little. I don't know just a shot in the dark does the voltage regulator even ground through the chassis or am I just grasping at straws?

thanks for all of your replies I will keep you updated.

 

I believe the regulator does ground through the chassis. i had an 81 f 150 that wasnt charging, and the mounting screws were loose. i retightend em and it worked again! well, for about a week. then the alternator craped out.

 

and the regulator will burn up by not being grounded