1995 Jeep Grand Cherokee Limited, I-6, close to 150K miles.
It cranks sluggishly. It actually starts ok because it's firing up on what may be the first rev but it's really slow sounding. Battery was about 30 months old. Spec. gravity thingy with the floating balls said cells were only at 75% charge. I checked system voltage with engine off and it was about 12 point something and with the engine running 13 point something to 14. Seemed better for awhile so I was been watching the vehicle's own voltmeter and it seems where it should be, near 14 with the engine running. I also removed and emery'd the posts and cable clamps.
It started to seem sluggish turning over again in the last few days so today I checked the battery cells and this time 50% to 75%. Okay, time for a new battery so I got a pro-rated warranty replacement. After putting it in I was hoping to hear a vigorous start. But nope, still sluggish with the new battery. Of course the new battery, not coming from a place that keeps them on trickle charge, isn't really fully charged so I am hoping after it really gets charged it will in fact cure the sluggish crank but is there anything else I should be looking for? Do starters get "weak" or more likely just fail flat out?
Also, is it normal to get oddly high battery voltage readings immediately after taking off charge, like in the 13's rather than 12 point something, maybe from "surface charge" or something? I'm not charging it at any great rate, just 3 or 4 amps....not much more than a trickle. SG doohicky said the cells were at 75%.
I would suspect the battery cables. Especially the ground to the chassis. The dealer actually found mine. The ground had nearly disintegrated. You don't normally see this because it is under everything. This is a common failure point for JGC's.
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14 is about right with the engine running, so the alternator MAY be off the list of suspects.
Cable materials tend to corrode, when shining up cables, do the one from the alternator to the body as well, and also the ones to the solenoid and starter.
Cold battery voltage depends on the temperature, but should only be checked after doing something like turning on the lights for few minutes, then measure with them on and off. Avoids reading a surface charge.
Wherever you bought the battery should have not only load tested the battery but also checked your charging system before giving you a new one.
Yes. Is called surface charge. I've also seen it on a leaky or open diode on an alternator, which is easy to check.
The specific gravity of a charged battery is 1.235 temp corrected.
What brand and load battery are you using? If you have a big bad fully charged Optima or Die Hard, it probably isn't the battery...but check.
Did this happen suddenly or slowly become worse?
Open circuit voltage test is:
Turn on headlights for 15 seconds, then turn them off and wait 5 minutes.
Remove battery cables and measure open circuit.
Fully charged is 12.6 volts
75% is 12.4 anything less means something is royally wrong.
Check voltage drop on cables: Pull the auto shutdown relay from the box on the passenger side under hood near battery. Should be marked. If manual, you'll need to jumper the clutch switch or have someone push it down.
With battery connected:
Measure from the battery post to the cable terminal with ignition in start position. Use a low scale. No voltage drop or cable is dirty, defective.
Measure from positive battery post with switch in start to stud on solenoid. Max 0.2 volts and 0.2 volts is not that good.
Measure from battery negative post and a clean spot on the engine block with switch in start. Max 0.2 volts and 0.2 isn't that good.
Measure from starter housing with switch in start to battery negative terminal. Max 0.2 volts and you know the rest.
Starters can start dragging, new ones aren't that shabby but make sure you get the right one for your year and engine.
I'd probably bribe a shop to check the alternator and starter before springing for either.
A well tuned 1995 ZJ should easily give 20 mpg at 75 mph cruise, with very little difference up and down hill or moderate load. Presuming you don't have a lead foot or a nervous foot and change speeds regularly.
21-22 is doable with nice clean air cleaners and a cat back.
In low speed traffic down to about 15 if lots of lights. On moderate speed traffic without too many lights, much closer to 18-19 if you drive to get up to speed moderately quickly and get the torque convertor locked up. Worst thing you can do is slooooowly bring it up, as the longer you are in lower gears the poorer the mileage. Hot rodding is also bad.
The CR mileage reports are about as valid as the government ones.
Want an RX-7? My 85 ZJ gets better mileage under any condition.
3-4 amps should be enough to charge it, but you need to make sure you leave it on long enough - at least overnight. If it's still showing
75%, I'd suspect your hygrometer is not accurate. So you don't keep chasing your tail with that, I'd take it to the place you bought your battery and ask if they'd measure the battery with their hygrometer and put that question to rest.
The surface charge thing is correct - voltage would start out higher right after a charge and drop down after sitting. 13.5-14 is about right with the engine running (charging it).
Once you eliminate the confusion factor of whether the battery is up to snuff or not, if it's still slow cranking, then pursue that.
On whether starters can get weak rather than fail flat out, someone else could better answer that. As billy ray suggested, you need to confirm integrity of all connections in the high current path to the starter, including grounds. Maybe the solenoid contacts are hight resistance, but I think they usually just get intermittent (one time it will crank right up, next time it just clicks) rather than constant sluggishness.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Well, today I finally found a Mercury Mariner Hybrid (basically an upscale Ford Escape) to test drive. I was a little disappointed. It road kind of rough over bumps and much to my surprise, unlike the Highlander which, as far as I could tell, has fully electric air conditioning, the MM Hybrid still has the compressor belted to the engine. Slow down and stop and when the engine shuts off so does the chill. I found that if I put the controls into MAX AC the engine stays running. But if I have to do that for much of the summer that kind of blows the whole hybrid business. So maybe the Highlander or just get a car. But I'm kind of psyched up for a hybrid so have to consider the Camry Hybrid. I did look over the Lexus Hybrid SUV but $55K would buy a lot of gas not to mention two Camry's.
Last week I drove about 120 miles and my first re-start after getting there was so sluggish it almost stopped while cranking but I guess a cylinder just happened to fire at the right moment and it started. I curtailed my visit and the few errands I did I left the engine idling the whole time. As soon as I got close to home I left it with a mechanic.
Naturally the next day he called to say they could find nothing wrong...it was starting vigorously. Charging system checked out and as I said previously the battery is new. I suggested maybe it was temp related so they let it get warmed up and still nothing.
He said putting in a new starter is about $270 all told and that's too much to do on speculation alone. I agree. When I picked up the car it was still starting vigorously and did so for about a day and then the sluggishness returned.
I am starting to notice a correlation between heat and this problem. I'm guessing the starter gets less functional as it gets hot although I suppose it could also be something in the engine making it hard to crank at high temperatures.
Yesterday after some long driving with progressively worse starts as the day went on it finally culminated (luckily within walking distance from home although it didn't prove to be necessary) in it not being able to crank at all. Being at a fast food place I placed an ice cube on the starter. Also spritzed it with water. Got back in the car and while it was still just barely there it did start up.
What failure mode is happening inside the starter (if that's what it is) that causes it to get weaker as it gets hotter?
It's still not a sure thing but while I might not want to spend $270 on spec I am willing to buy a rebuilt starter for about $75 and put it in myself on hope alone.
Anything I should know about starter R&R on 1995 Jeep Grand Cherokee Limited inline 6? I've never done one but everything I've read makes it sound pretty simple. Disconnect the battery, disconnect wires from the starter, unbolt it and bolt in the new one, etc.
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