cant get my 620 to start

[squatches]

ok so after i swap my motor into my other truck get everything hooked up fire it up and nothing. so i trace everything back grounds fuses connectors everything find out its the coil get a new one put it in and it firesa up. but after i parked it and came back the next day it wont even turn over all i get is this buzzing noise from the starter and no fire to the coil at all and i have no clue what to check or do now. the engine is a l20b

[Grey_Matter]

ok so after i swap my motor into my other truck get everything hooked up fire it up and nothing. so i trace everything back grounds fuses connectors everything find out its the coil get a new one put it in and it firesa up. but after i parked it and came back the next day it wont even turn over all i get is this buzzing noise from the starter and no fire to the coil at all and i have no clue what to check or do now. the engine is a l20b

 

sounds like a dead battery

[D@tsuks]

What I would check;

Is the battery fully charged

Check power and ground cables (I had corrosion in the lug that connects to the solenoid but wasn't readily visible, it would have 12 volts but under a load it went to zero volts)

Check the small wire at the solenoid (when you go to turn it over this wire should have 12 volts)

Check starter and solenoid. (sometimes your starter could have a band winding and when you go to crank it over it will engage the bendix but will not spin the motor and get stuck)

 

 

[banzai510(hainz)]

was truck running before you pulled the motor? Why I ask this is if running before then the coil was not bad.

 

Now you could have a dead battery. or a bad starter? or loose connection,bad cables weak alternator not charging the battery making it look like like battery is bad.

 

This is a simple fix

 

remember you want a point coil in there with the ballast resisitor if still running points distributor.

 

If you have power to the coil?

 

the coil only fires when points are open. points close to charge the coil then when points open the field collaspesthru the 2ndary windings then goes to the center wire to the correct plug wire

 

http://olddatsuns.com/620tech.htm is your reading homework

[squatches]

i dont think it has anyting to do with battery it has full charge and is brand new stuck it in my dodge and it turned it over so i know its not that, engine was running when pulled and was running after we put it back in but next day the truck wouldnt start and the coil had no power to it at all got new coil anyways never hurts to have a new part i think it may be what d@tsuks said (Check starter and solenoid. (sometimes your starter could have a band winding and when you go to crank it over it will engage the bendix but will not spin the motor and get stuck) because i can hear a buzzing noise from the starter when trying to crank it.

 

 

 

 

[Dirttrack510]

i dont think it has anyting to do with battery it has full charge and is brand new stuck it in my dodge and it turned it over so i know its not that, engine was running when pulled and was running after we put it back in but next day the truck wouldnt start and the coil had no power to it at all got new coil anyways never hurts to have a new part i think it may be what d@tsuks said (Check starter and solenoid. (sometimes your starter could have a band winding and when you go to crank it over it will engage the bendix but will not spin the motor and get stuck) because i can hear a buzzing noise from the starter when trying to crank it.

Check to see if you have a good ground from the engine to the body. there should be a heavy wire in the alternator loom that goes from the motor to the body over by the battery. My race car did exactly what your talking about and I had forgotten to hook up this ground wire when I built the car.

[skunk]

you might have done what i did and left the fuse box un pluged :lol:

[banzai510(hainz)]

disconnect the power to the coil. The power wire. Turn key to ON. now with the old coil in there. if you have 12volts then plug it in the coil and measure again. if loose 12volts then I assume the coil is shoring out but if ita a point it could short out if points closed.(i forgot myself)

I have feeling old coil is good as I never seen one go bad.

[datsun brat pack]

if you have the 78 or newer ignition the ecm on the distibutor can go bad i had one that would run gust fine and then in would stop runnig i also change the coil and it ran then it would stop running and it would stop firing out of the coil . the ecm controls the spark i hope this helps lol.

[datzenmike]

...and the coil had no power to it at all ...

 

You have to have the motor turning over first before trouble shooting the coil. Sounds electrical: fixing this will likely fix the coil.

 

Instead check and clean both battery terminals as well as the ground cable where it bolts to the head and the positive where it bolts to the starter. Just above the starter cable on the solenoid is a Black/Yellow wire that comes from the ignition switch. This wire signals the starter to.... start, by energizing the solenoid. If the battery is fully charged and you jumper across this Black/Yellow wire and the positive starter terminal the starter should engage and turn the motor over. This test will eliminate the ign. switch as the starter problem.

 

 

If there is no power to the coil, changing it will do nothing. Power comes from ignition in the on and start position to the + coil terminal, through the coil and out the - terminal and to the distributor points which open and close to ground when motor turning. Take the coil and get your money back.

[squatches]

well i tried jumping the starter nothing but a clicking noise, pulled off tried it off of the truck same thing gonna pull starter apart and check brushes and everyting else. hope starter is all it is thanks for all the help so far guys

[squatches]

ok i need help again! put new starter in and nothing i can jump the starter and get it to work but with the harness i get nothing but a clicking noise from the carb now :blink: ive checked all of my grounds and connections all looked good even cleaned them up and nothing

[datzenmike]

The clicking on the carb is normal and a good sign that the idle cut solenoid is working.

 

Check that there is 10-12 volts on the start wire (Black/yellow) when the key is in the start position. I had the same problem on my 710. It would click a couple of time before it caught and began cranking. The problem is there isn't enough voltage getting to the starter solenoid to activate it properly. What I did was use this weak signal to power a relay that sends a strong 12 to the starter. Hasn't failed me once since doing this.

[squatches]

what type of relay did you use and how did you set it up?

 

thanks

[datzenmike]

720 are full of them but there are 3 or more type. Be sure to get the plug and some wire when you cut it off. Usually they are colored blue/black brown try the blue ones. I'm not sure where this one was but check the drivers side kick panel above the fuse box on the 720 or up under the dash on the passenger kick panel. D-21 and Pathfinders have lots under the hood passenger side.

 

 

1 goes to the Black/Yellow trigger that was on the starter. 2 goes to ground

 

3 goes to a 12 volt source and 5 is now the new trigger wire that goes to the starter solenoid.

 

 

When not being used 5 is not connected to 3 but when the key is turned to start the weak signal goes to 1 and energizes the coil and passes out 2 to ground. When energized 3 (12 v) is connected to 5 and to the starter.

 

 

.

[squatches]

ok thanks im gonna go to the jy tommorrow and see if i can find one

 

and what the hell is this box/relay that was under the dash it keeps clicking to when i turn switch is that normal?

 

 

[datsun brat pack]

IM realy soory for not geting back to u guys iM still learning how to use this forums lol not the best on the computer.Any way about the relay it looks to me a driver side seat belt buzzer but dont quote me on that .I still dont no the yr or make of truck or motor size . I WILL DO MY BEST TO HELP BUT I DONT KNOW EVERY THING LOL.

[squatches]

well for now i just took the black and yellow wire from the switch and ran a new wire straight to the starter and back to the switch everything worked after that going to add relay when i get into wire harness for the e fans