Ok Jeep gurus, I have a question for you all. I have a 1985 cj7 with 4.2 out of a 89 an a tf999 transmission. The Jeep has been running good. But I have had some issues with it starting from time to time. Once in a while I will go to start it and it will just be dead. Won't turn over. Acts like there is no battery. So I have replaced the starter solenoid, battery, battery cable, ground cable, and starter. Once I did all that, the issues seemed to have disappeared.
So then last night after I was driving around all day want to go play some hockey an the jeep won't start. This morning I check the battery. Battery tested good. Went to check voltage at solenoid, found it was only getting 4.5 volts in the run position. Thought oh ignition switch must be bad, run to the auto parts store installed that. Turn key and nothing again. No click, no whining just dead. So i jump the starter by using jumper cable from battery to starter, it tried to start, very weak crank, makes me believe the starter is good. I then try the key again an what do you know it starts right up no problems. So now I thinking i have some sort of a cross wire or melted together wires. Maybe it's a neutral safety switch issue. Then I looked at the solenoid and the 12 volt wire is not even hooked up . So now I'm not really sure where to look for the issue. I thought the 12volt wire was to energize the starter solenoid
I guess I just have to wait until the next time it decides not to start. All that was on 09-10-2014.
OK so jeeps been running great lately, no problems. Decided to take it out this weekend (11-1-2014) do a little 4 wheeling. Jeep stalls out, then it doesn't want to start. Turn the key an its dead. No clicks, no wo wo wo, no nothing like the battery was disconnected. Check battery cables they are good. Still no start, all quite. So then i think maybe neutral safety switch. I wire the starter solenoid to ground. (Not worried if it can start in gear or not). Go an test, still nothing. So now I'm at a lost, freaking out a little bit that I'm going to have to hike out the 5 miles. Think I'll try one more time an what do you know it starts. So I high tail it out of the woods an get home.
Jeep had no issues today. So I'm at a lost. Could there be a crankshaft sensor? Can't fine one on line.
If any of you have experience or thoughts on what I should test/look at next, would all be greatly appreciated.
Scott
This is what bothers me the most...
Went to check voltage at solenoid, found it was only getting 4.5 volts in the run position
How/Where EXACTLY did you check for voltage at the starter relay,
While the key switch was in the 'Run' position?
if you checked at the small 'I' terminal on the side of the starter relay,
Without having the starter relay activated, this would be about correct.
That terminal in the 'Run' position would read about 4.5 volts since you are reading the coil load AND the ignition resistor wire with the key switch in the 'Run' position.
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If you had 4.5 volts showing at the BATTERY POSITIVE CABLE to the starter relay,
That's DISTURBING at the very least!
Batteries CAN, AND DO, break bridges between cells over the summer from heat expansion.
You usually don't notice this until FALL, when temperatures get cooler, the lead contracts and a gap opens up between cells.
Since this is an INTERMITTENT problem (until the bridge goes ahead and corrodes or arcs out) you won't have the issues full time, and the battery will often test 'Good' on voltage,
But if you FULLY LOAD TEST IT (Testier with resistance 'Heating' element and full size battery clamps) you won't find that crack between cells until it want's to show itself...
A FULL ON Load Test will OVERLOAD that crack, and it will show up,
Those little dinky testers that 'Interpolate' an amperage load won't show it up.
SAFETY WARNING:
I suggest you DO NOT be leaning over that battery when you fully load test it, since an arc in the crack, often as not, blows the battery up, and you DO NOT want that to happen while your face is 6" away from the battery...
I used to throw a small blanket over the battery when I suspected this condition. Saved me MANY times from splattering acid all over the engine bay, not to mention in my face!
Hook up the tester clamps, throw the blanket or heavy towel over the battery, and FACE AWAY from the battery when you push the test button.
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The SECOND thing that comes to mind is the battery cable.
Since (I Assume) you tested at the starter relay battery cable, it's not the starter relay itself, but the cable is suspect...
Key switch in the 'Run' position would NOT have activated the starter relay, so there would have been ZERO volts at the starter cable connection...
This would indicate a bad positive battery to starter relay cable.
Again, Hook a LOAD tester to the starter relay/battery cable terminal, and load test.
If you don't' get the same results as when you tested the battery by itself, the cable is the issue.
That cable should test just like testing the battery directly.
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If battery and cable check out,
Then it's a 'Ground Path' issue.
The 'Ground' simply isnt' letting enough current through to turn the starter or activate the starter relay.
It seems you ruled that out by MANUALLY grounding the starter relay to the battery directly.
The starter relay SHOULD have activated if it was a 'Ground Path' issue...
So I'm not suspecting the 'Ground Cable' at this point.
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Now, I owned and operated a starter, alternator and engine electrics shop, selling batteries, visiting the manufacturers and learning about batteries for over 10 years...
I can tell you from personal experience, late fall and early winter were my best battery sales season.
I often sold as many batteries in the three months of fall as I did the rest of the year for 'Non-Commercial' vehicles and over the road commercial vehicles.
This IS the season all those battery issues present themselves that have accumulated over the winter, spring and summer...
So in the fall, I ALWAYS suspect batteries first when terminals and cables test out, it's just about GOT to be the battery...
A battery at 32°F is at 1/4 of it's cranking power.
The amperage is there, the cold electrolyte takes 3 times longer to convert chemical power into electrical power,
And the average engine is 300% HARDER to start at 32°F than it is at 75°F.
So you are down 3/4 on available INSTANT (Surface Charge) energy,
With an engine that is 3 times harder to get fired, and you show up battery problems or starter problems pretty quickly...
And that 'CCA' or 'CA' rating on the top of the battery doesn't mean squat.
It's bragging from the battery manufacturer since virtually no batteries live up to the 'Rating' when you actually chill them to 32°F (CA rating) or to (Zero) 0°F (CCA) rating...
It's simply chemical physics, the electrolyte doesn't work as well converting the STORED chemical energy to 'Electrical' energy at those temps...
Since it's physics, it can't be sidestepped by some fancy advertisement.
It's just a fact of the universe that chemical reactions slow down with temperature decreases.
One tip is, INDUSTRIAL or ROUGH SERVICE batteries are usually closer to the rating shown than 'Consumer' batteries.
Industrial customers are more likely to actually TEST the batteries to see if they meet the intended application, so they can't lie as much and get away with it,
Where 'Consumer' batteries lie like crazy since the average commuter isn't going to do cold testing just to see if his particular battery lives up to claims.
I found this out when the very same battery, very same part number, very same size and weight batteries came in with 'Consumer' and 'Commercial' labels, stating different CCA and Amp Hour ratings.
Quick testing by letting the batteries sit out in the cold confirmed the 'Commercial' battery labels were closer to the actual output,
While 'Consumer' batteries were WAY OFF, much lower than the claims on the label,
But just exactly what the ACTUAL testing of the 'Commercial' batteries was (since it was the same battery with a different label)
The kicker was, the 'Commercial' batteries were a CHEAPER suggested retail price, for EXACTLY the same battery as the higher priced 'Consumer' battery.
So the label with the bigger (unsubstantiated) claim cost more for exactly the same battery!
(higher profit margins for retailers, it's all about the bucks)
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Now, INDUSTRIAL or ROUGH SERVICE batteries are usually made a little different...
The larger versions of Industrial or Rough Service batteries often have plates in the cells that are 'Captured', they can't pop up and come loose when they are pounded around.
The industrial or 'Rough Service' batteries often have a woven 'Paper' that zig-zags between plates to keep them from shorting out the cell if they come loose.
Industrial or 'Rough Service' batteries usually have a 'Mud Tray' at the bottom of the battery case.
The plates are moved up a little, allowing the scale produced by the plates to fall to the bottom and NOT short out the plates.
These things are usually only on the LARGER sizes of batteries, when you get out of 'Car' size batteries, so it's not much of a big deal to us,
But you CAN get these things in 'Car' size batteries intended for Farm Equipment...
Since farm equipment, and small industrial equipment like 'Bobcats' get thumped regularly, they need a battery that will take the abuse.
That's were the 'Farm Store-Rough Service' batteries come in...
If you live in an area with a farm store, IGNORE the CA or CCA rating and get one of those if you have battery issues regularly.
It will probably live when the 'Consumer' batteries don't.
For the mild off roader,
The 'Marine Starting Batteries' (NOT the 'Deep Cycle Marine') are usually built very well, very sturdy, and reasonably priced.
Marine applications beat the
out of batteries, so they just plain build them stronger.
The other thing I like about a 'Marine Starting' battery is they are about half way between a 'Deep Cycle' and a 'Starting' battery.
They will discharge a little deeper/more often and still recover reasonably good,
They don't need a 'Trickle' charger to keep them alive over long term like 'Deep Cycle Marine' batteries do,
They aren't rated for 'Super Duper' CA or CCA, but they are PLENTY strong,
And they hold a charge MUCH longer during lack of use than the average 'Starting' battery...
They also tolerate DUAL BATTERY arrangements MUCH better than either 'Starting' or 'Deep Cycle' batteries do since virtually all marine applications have dual batteries... They are ENGINEERED for dual battery banks...
Just some tips, take em or leave em!
