Help troubleshooting an electrical issue... I think

fueg0 · 06-22-08, 09:55 PM

I just bought my first FJ40 about 2 months ago, and it's developing a nasty habit of not wanting to start.

The more I drive it (in one day) the more likely I am that I will have to push-start my truck.

I can drive it for 2 hours, and by the time I get to my destination, I can turn off the ignition, and immediately try to re-start, and it will s l o w l y crank, and about half the time, start. The problem becomes more pronounced the more I drive the truck in the same day.

If I let it sit overnight, it will crank right up like nothing is wrong. I had the battery tested, and it's a red-top Optima (which tested fine), and I had the alternator tested too (50 amps is what the guys at Autozone told me). If the battery is testing okay, and the alternator is just a little shy of what's supposed to be 'normal', what in the heck is going on ?

I've searched this forum high and low, and I can't seem to find anyone that's had this problem before (I'm sure there are, I just haven't stumbled across their posts yet)

help!

thanks,
--jeff

bsmith123 · 06-22-08, 10:18 PM

Check the voltage not the amperage--should be putting out about 14 volts then it's enough to charge the battery

check for loose and dirty connections also--if you have high resistance the charge wont make it through

look for bulges in your battery cables---a sure sign of corrosion

Joe Egolf · 06-22-08, 10:19 PM

I would check the battery cables and connections.If the cables are old or have been replaced with cheap cables they might be heating up as you drive and restricting starting power to start a hot engine?

Bret · 06-23-08, 05:54 AM

I've never experienced it but you can apparently "heat soak" the starter and it won't work either. Same theory as above though, clean all your connections, check your wires etc.

http://forum.ih8mud.com/60-series-wa...heat-soak.html

ranger · 06-23-08, 08:03 AM

Take your vehicle to your local Kargens/Schulks or similar parts store and have them hook up the tester to the cruiser. If you don't have the skills, this is the best way to go instead of getting the 100 guesses method.

jrtredo · 06-24-08, 12:01 PM

i would also lean toward battery cables. check these to see if they get warm. Also check your ground strap to frame and your cable from starter to switch

fueg0 · 06-24-08, 12:22 PM

So I'm assuming that heat indicates resistance, which could indicate corrosion ?

sorry if this is an asinine question, it's just that I know very, very little about electrical, well, anything.

thanks for pointing me in some direction!

--jeff

Coolerman · 06-24-08, 12:35 PM

Heat can contribute to a high resistance connection. If the cables are old and neglected they may be corroded inside the covering or the crimped section could be corroded. A corroded connection has a high resistance and will get HOT when subjected to the high current of the starter. This high resistance will starve the started of current causing it to drag or turn slowly.

Personally I would just pull off both battery cables, take them to a parts store and tell them to give you two new ones. That way you KNOW that is not the issue. They are not too expensive.

jrtredo · 06-25-08, 08:12 AM

yes heat will indicate resistance. i have a jeep that would turn over real slow especially after driving a while and it turned out to be the cable running from the starter to the switch. it was old, but looked just fine. one day it just started to burn right up. never even noticed this before but it would get real hot

06-22-08, 09:55 PM	#1
fueg0 IH8MUD Rookie Join Date: Apr 2008 Location: between a Rock and a Weird Place Posts: 14	Help troubleshooting an electrical issue... I think I just bought my first FJ40 about 2 months ago, and it's developing a nasty habit of not wanting to start. The more I drive it (in one day) the more likely I am that I will have to push-start my truck. I can drive it for 2 hours, and by the time I get to my destination, I can turn off the ignition, and immediately try to re-start, and it will s l o w l y crank, and about half the time, start. The problem becomes more pronounced the more I drive the truck in the same day. If I let it sit overnight, it will crank right up like nothing is wrong. I had the battery tested, and it's a red-top Optima (which tested fine), and I had the alternator tested too (50 amps is what the guys at Autozone told me). If the battery is testing okay, and the alternator is just a little shy of what's supposed to be 'normal', what in the heck is going on ? I've searched this forum high and low, and I can't seem to find anyone that's had this problem before (I'm sure there are, I just haven't stumbled across their posts yet) help! thanks, --jeff

06-22-08, 10:18 PM	#2
bsmith123 IH8MUD Lifer Join Date: Oct 2007 Location: panhandle florida Posts: 1,029	Charging Check the voltage not the amperage--should be putting out about 14 volts then it's enough to charge the battery check for loose and dirty connections also--if you have high resistance the charge wont make it through look for bulges in your battery cables---a sure sign of corrosion __________________ B Smith123 Chaos, panic, & disorder - my work here is done. The easy way ain't cheap and the cheap way ain't easy!!! 71 FJ frame off build "UGLY BETTY" 33 in BFGs, 4 inch HFS lift, Durabak lined tub, and a soft top in a box! Now sportin a 2F and 4 speed

06-22-08, 10:19 PM	#3
Joe Egolf IH8MUD Regular Join Date: Jun 2006 Location: W.Suffield Ct Posts: 437	wont start I would check the battery cables and connections.If the cables are old or have been replaced with cheap cables they might be heating up as you drive and restricting starting power to start a hot engine? __________________ 1981 BJ42

06-24-08, 12:35 PM	#8
Coolerman IH8MUD Lifer Join Date: Jan 2004 Location: Lexington, KY TLCA# 13645 Posts: 2,690	Heat can contribute to a high resistance connection. If the cables are old and neglected they may be corroded inside the covering or the crimped section could be corroded. A corroded connection has a high resistance and will get HOT when subjected to the high current of the starter. This high resistance will starve the started of current causing it to drag or turn slowly. Personally I would just pull off both battery cables, take them to a parts store and tell them to give you two new ones. That way you KNOW that is not the issue. They are not too expensive. __________________ !Oy my 1971 FJ40 Not Road Legal http://tinyurl.com/47zpb (My Web Site) http://tinyurl.com/2h6hc7 (Nut and Bolt Spreadsheet)

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06-23-08, 05:54 AM	#4
Bret IH8MUD Regular Join Date: Oct 2003 Posts: 493	I've never experienced it but you can apparently "heat soak" the starter and it won't work either. Same theory as above though, clean all your connections, check your wires etc. http://forum.ih8mud.com/60-series-wa...heat-soak.html

06-23-08, 08:03 AM	#5
ranger IH8MUD Addict Join Date: Jan 2003 Location: Idaho Posts: 932	Take your vehicle to your local Kargens/Schulks or similar parts store and have them hook up the tester to the cruiser. If you don't have the skills, this is the best way to go instead of getting the 100 guesses method.

06-24-08, 12:01 PM	#6
jrtredo IH8MUD Rookie Join Date: Jun 2007 Posts: 31	i would also lean toward battery cables. check these to see if they get warm. Also check your ground strap to frame and your cable from starter to switch

06-24-08, 12:22 PM	#7
fueg0 IH8MUD Rookie Join Date: Apr 2008 Location: between a Rock and a Weird Place Posts: 14	So I'm assuming that heat indicates resistance, which could indicate corrosion ? sorry if this is an asinine question, it's just that I know very, very little about electrical, well, anything. thanks for pointing me in some direction! --jeff

06-25-08, 08:12 AM	#9
jrtredo IH8MUD Rookie Join Date: Jun 2007 Posts: 31	yes heat will indicate resistance. i have a jeep that would turn over real slow especially after driving a while and it turned out to be the cable running from the starter to the switch. it was old, but looked just fine. one day it just started to burn right up. never even noticed this before but it would get real hot