1970 FJ40 won't start guessing electrical

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M

my73fj40

Joined
Oct 14, 2006
Threads
12
Messages
37
Location
Fruit Heights
1970 FJ40 with original engine
Let it sit for few weeks then wouldn’t start. Charged the battery and started right up. Started next day, but did not start on 3rd day. Could hear fuel pump and amp meter on dash moved so I know I have a good connection. Again charged battery and started right up. Took to auto zone got starter, alternator, and battery tested all passed. Bought a new battery and new cables anyway.
Same problem. Checked voltage regulator. Here are the numbers on my voltmeter tester when the key was ON.
Battery 13.1
IGN 11.3
F 10.9
Don’t know if those are good numbers. I am not good with electrical things so any ideas would be appreciated.
 
Last edited:
Check and make sure u have a good ground.....
Take your starter to autozone....they will check it for free....
 
You have a slow drain on you battery it sounds like. You don't have a radio or other electronics on it that are not ran through the ignition switch do you.

I have a radio that is not through the ignition but through a switch, if I don't remember to turn off the switch it will eventually run the battery down. This is a small drain and takes many days to do this.

I've also seen sticking brake lights switch do the same thing. If the battery, alternator, and starter all checked out you have a slow drain.
 
you may also want to check and see if all the connector off the alternator are good...and the ones in that line of wires...they like to corrode and deteriate and come apart...then it will not be charging the battery back up
 
Thanks for the replys. cleaned all the connections on the alternator and starter. so far it is starting but it's too early to tell.
I was also thinking it is a slow drain, but not sure how to test it. no radio, so i'm not sure where else it could be draining from.
 
fjgoober said:
You have a slow drain on you battery it sounds like. You don't have a radio or other electronics on it that are not ran through the ignition switch do you.

I have a radio that is not through the ignition but through a switch, if I don't remember to turn off the switch it will eventually run the battery down. This is a small drain and takes many days to do this.

I've also seen sticking brake lights switch do the same thing. If the battery, alternator, and starter all checked out you have a slow drain.
Click to expand...

X2

Might help if had more information. A stock 70 FJ40 would not have electric fuel pump. Dod you have a radio?

I would pull the ground wire off the battery. If you have a drain there will be a voltage reading between the gound terminal on the battery and the ground wire with everything off. If you have a voltage reading pull the fuse one at time. If pulling any fuse causes the voltage reading go away your on the right track. I installed a radio in my 68 that has 12 volts all the time to keep the time and station. But a second 12 volt source to power the radio itself. This is not enough to drain the battery. I would do what ever it takes to stop the cause of any voltage reading first and see if it help with the starting. If it does you need to figure why it drawing so much amperage that is causing your battery to drain.

If it was poor connection a good battery weaker once it turn off and would be better after sitting for a while. A drain it will be the opposite.
 
my73fj40 said:
1970 FJ40 with original engine
Let it sit for few weeks then wouldn’t start. Charged the battery and started right up. Started next day, but did not start on 3rd day. Could hear fuel pump and amp meter on dash moved so I know I have a good connection. Again charged battery and started right up. Took to auto zone got starter, alternator, and battery tested all passed. Bought a new battery and new cables anyway.
Same problem. Checked voltage regulator. Here are the numbers on my voltmeter tester when the key was ON.
Battery 13.1
IGN 11.3
F 10.9
Don’t know if those are good numbers. I am not good with electrical things so any ideas would be appreciated.
Click to expand...

You say: ....when the key was ON. Was the engine running (at idle)? Because "Battery 13.1" is pretty high for a battery if the key is on and the engine is off. 12.6 is the limit for a "good" battery after charging and 2 hours rest.

Rudi
 
ok, aparantly I did not test it correstly for a slow drain. slow drain is the issue. now how to fix it. I tested each fuse connection and found out that the 3rd fuse on the blopck is the problem. once i took out the fuse, no drain. can't seem to figure out what was on but it doesn't seem to stop regular function. the 2 wires just go up to the big ball of wires behind the dash so I don't know how to trace the source. should i be worried that something is not on, or as long as it runs it's ok?
 
According to the Haynes manual there are 6 fuses. The 3rd fuse from the top is a spare.....
fuseblock.webp

Hmmmm,:hhmm:

Rudi
fuseblock.webp
 
the lower right fuse block is what I found on my '72 FJ - I would think that an '73 FJ also had 8 positions instead of 6

in fact, the text (left column) of the Haynes manual Rudi posted also lists 8 fuses
 
bj40green said:
According to the Haynes manual there are 6 fuses. The 3rd fuse from the top is a spare.....
View attachment 619565

Hmmmm,:hhmm:

Rudi
Click to expand...

I checked the cover on my 68 and it matches the Haynes manual. Not around my 70 to check but other than the bib lights no longer there and parking light in the turn signals plus side markers the wiring should be close. The upper three fuses have power all the time and the lower three only when the ignition switch is on. Do you a radio installed? With the number three fuse pulled check all your lights including hazard flasher with the ignition off. Do they all work? Turn signals and backup light only work with ignition switch on. Does your horn work? It's not that uncommon to have the wires moved to the spare fuse if another fuse socket goes bad.
 
How old is your battery? It sound like it is shot.
 
When you say it did not start, did you hear the starter solenoid pick up at all? If it happens again, monitor battery voltage while tuning the key to start, if voltage drops way below 12v, you know the battery is low, if it doesn't drop, you know the starter solenoid is bad. They can be intermittent.
 
sorry, let me clarify. I now own a 1970 FJ40, used to own a 1973 so my username is not exactly what I have. Thanks for the manual pic. i tested the other points and it is just as the manual says. except #3, its a spare but it has 2 wires on it. everything else works so i guess I won't worry about the 3rd one missing it's fuse. there probably was something aftermarket installed for those 2 wires to go to, but I guess its not in use anymore, it's just been a pain in the butt draining my battery for so long. Thanks for everyones help, now I just have to figure out why when my right turn signal goes, both seem to flash, but the left is just fine. the frustration will be worth it when i take it to MOAB UT in 2 weeks!!!!!
 
how is your ground at the turn signals ?
 
my73fj40 said:
ok, aparantly I did not test it correstly for a slow drain. slow drain is the issue. now how to fix it. I tested each fuse connection and found out that the 3rd fuse on the blopck is the problem. once i took out the fuse, no drain. can't seem to figure out what was on but it doesn't seem to stop regular function. the 2 wires just go up to the big ball of wires behind the dash so I don't know how to trace the source. should i be worried that something is not on, or as long as it runs it's ok?
Click to expand...

DSRTRDR said:
how is your ground at the turn signals ?
Click to expand...

I believe he has solved which fuse the drian is coming fom. Just not sure if he is talking about ball of wires behind the dash. If it's a wiring harness all the lighting should be check. If just a bunch a loose wires it may just be from a radio that was installed and later removed. Have a couple of cruisers like this. Just remove the wires from the fuse block, Take them up and call it good.
 
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