Symptoms of a bad battery / connection?

[Camo-5]

For the first 5000 miles of my ownership, my XJ ran flawlessly. All of sudden, I started having problems with it missing and sputtering while I'm cruising down the road, both highway and city speeds. I can stomp the gas, and it accelerates fine, but when I back off, it starts to sputter again. I also hear a 'pop' from under the hood like back pressure into the airbox or something. It only lasts 10 seconds or less, then runs great for an indeterminate amount of time and does it again. I went to start it the other day and had to pull the battery cables and clean everything up to get it to start. Shortly after, it sputtered again. It wouldn't start again today and I had to move the connections on the battery again to get it to run and it sputtered 2 or 3 times just driving to lunch and back.

Could my battery or connections be bad causing an improper spark? Before I dive into all sorts of other ideas, this could be a simple fix. I have no idea how old the battery is, so I'll probably stop on the way home and buy a new battery and connections. Any hope this is my only issue?

Thanks!

 

[hanaxj87]

Do you have to jump start it? The auto parts store can check your battery.

If the battery is good the sputter might be the TPS {Throttle Position Sensor}

Good Luck

Nick

 

[Matthew Currie]

Does it crank well after you move the connections? Does voltage at the battery read all right? Chrysler fuel injection systems have a reputation for running badly when battery voltage is off, and especially when the battery is not taking a charge properly, such as after boosting a stone dead one. The battery acts as a filter to the chopped DC output of the alternator. If you have either bad battery or connections it can affect running. But before springing for a new battery I'd make sure the connections are clean (scraped or brushed shiny, clamps tight, etc.) and the cables good. It would pay to have a voltmeter and take a reading straight from the battery posts after it's sat for a while, to see if it's holding proper voltage.

 

[92DripCherokee]

if youre losing all of your electric power at once, its a bad connection, no doubt.

if the engine is cutting out, and there is still power to the other circuits...it could also be a failing crank position sensor, or a very badly worn distributor cap. I've been through both of these movies before.

 

[Camo-5]

MC, yes, it cranks perfect after moving the connections, but seems to crank longer recently than it did weeks ago before the problem started. I have recently been swapping seats in the XJ, so the battery died a week ago after working on the jeep for a couple hours. I had to jump it and it ran like crap for about 15 minutes (same sputtering problem). It wouldn't idle witout me keeping the rpms up around 1200 or so. What makes me think the battery is toast is that it died after having the doors open for only a couple hours. I've left the door open on my Ram a couple times for a whole night in cold weather and she still cranks fine.......

92DripC, I think this may be a combination of both bad connections and bad battery or the battery just isn't charging because of the bad connection. Not sure yet. I replaced the cps only a 1000 miles ago for a different issue and the cap, rotor, plugs, etc only have about 2000 miles on them and they are quality parts.

The battery is about 5 years old, so I'm going to replace it anyway...I'm also going to pull the cap and make sure it isn't fouled out for some reason. Hopefully it's just something simple which I think it is since I still get close to 20mpg and it runs great....most of the time.

Thanks everyone and I'll report back when I find out what it was....hopefully....

 

[5-90]

What year?

On my 87 (RENIX rig,) I had a loose auxiliary cable causing me fits - I replaced the cable (a precursor to what I do now, in fact,) and the problem went away. The "auxiliary" cable is the one that feeds distribution - which feeds the ECU and the ignition and ...

On later models, there will be two positive cables as well - one to the starter motor (6AWG, usually) and one to the PDC (probably 6 or 8AWG.) If this latter cable is starting to corrode internally, you could have similar problems. Try gently wiggling this cable with the engine idling and see what happens.

Also, check and clean your grounds. The main grounds on RENIX will be at the passenger rear-ish of the engine block (near the dipstick bracket - it's the main ground for the engine,) and at the rear of the cylinder head up on the firewall. On 1991-up rigs, there is an additional main ground on the fenderliner near the battery.

Where they contact the chassis, the sheetmetal should be cleaned down to bare metal, the lug cleaned or replaced, the screw cleaned or replaced, and corrosion inhibitor should be applied - especially at the main chassis grounds, as they provide the "ground reference" for the ECU (there are a number of ancillary system grounds as well.) A "floating" ground (caused by a contaminated or loose connection,) would raise all sorts of Hell with your system - and be a bear to track down.

 

[Camo-5]

5-90, It's a 97. All great ideas. Thanks for taking the time to type that all out. I checked out most of them last night, but replacing the cable is something I did not do....yet. I replaced the battery terminals, had the battery checked (it's good) and gave the throttle body a good spray down with tb cleaner. I definitly aggrivated something because it chugged and sputtered for 3 miles on the way to work. It was so bad I had to come back home and get my truck to drive in. Cleaning all that off definitly increased my throttle response (when it wasn't chugging), so it was due. This really makes me think it's the tps now. My flaps down the road has one in stock for $70, so I'm going to try that tonight along with more electrical investigation.

Changing the terminals has helped the crank time and strength so I've solved that issue. I'm convinced this was a seperate issue from the chugging/sputteing/popping issue.....

Just to reiterate the problem: I have a random (although seems to be increasing steadily) problem where my engine will chug and sputter when at low rpms, both city and highway and at all temps. When I push on the gas to maintain speed, it will bog and I hear a 'pop' through the airbox, almost like a mini backfire but not as loud. If I stomp on the gas, she takes off and doesn't chug or miss. Also, if I accelerate quickly from a stop it runs fine, as soon as I let off the gas to maintain speed, it bogs, sputters and pops again. It also seems to idle fine. As soon as I come to a stop, it smooths back out.

 

[bigalpha]

I recently got a new TPS from Advance Auto Parts, part number EC3313 and it was only $40. Mine is a 95 though.

 

[Camo-5]

Ok. So it's not the TPS. I replaced it tonight and it's just as bad. The problem is now even getting worse. I could barely make it to the end of the block and now I notice a lack of power at higher rpms. I'm stumped. I recently replaced the coil, dist cap and rotor. I took a look at them an there was actually a bit more build up than I thought so I cleaned them up. I can't take the xj for ride for a bit to see if that fixed it, but my guess it no way could it be that easy. Not with the severe bucking....

I also cleaned the air cleaner element (K&N) and thouroughly cleaned the trottle body. It was pretty gummed up also. I check all the electrical connections from the battery to the grounds and fuse panel, all the sensor connectors near the tps, etc. Not sure where to go next. After changing the TPS with no success, I hate to keep replacing $80 sensors randomly. I've already changed the cps for a different problem months ago and that usually causes no starts. Could it be the MAP sensor? From what I read not likely.....any other ideas?

Oh yeah, it is definitly backfiring. I was reving the engine after the tps replacement and I got a nice pop from the air cleaner box. Does this help anyone out with a diagnosis?

 

[j99xj]

Bad upstream (closest to the engine) oxygen sensors can cause what you describe.

 

[XBoBJ]

read through this, i was just having the same sympthoms, check your gas pressure
http://www.naxja.org/forum/showthread.php?t=968150

 

[Camo-5]

Thanks XBoBJ. Glad you found your issue! This one is a litle different though. It runs decent, but not great at high rpms. There seems to be an issue at lower rpms, yet idles ok - most of the time kinda wierd.

Anyway, I'm formulating a new theory. Last night I cleaned off the rotor and cap contacts. Drove it to work today and no issue! I'm not holding my breath until it makes it a few trips to work and doesn't do it anymore. What ticks me off is the cap and rotor only have about 3000 miles on them. Here is my theory: When I was trying to figure out my no start condition, I replaced the coil, cap, rotor, wires, plugs, etc. If I remember right, I got a good coil and the only cap and rotor I could find in stock was a cheapo (I had intentions of replacing it with better stuff, but you know how that works....). Back to my theory. I'm thinking the cheapo cap and rotor couldn't handle the intense spark of the new coil. As I mentioned there was excessive fouling inside the cap and rotor for only 3000 miles. I'll take a closer look tonight when I replace them both with OEM MOPAR parts. Gosh, I hope it was this simple......

 

[Shorty]

assuming the correct cap and rotor were installed (there are two different distributors possible) the carbon tracking/ fouling is a result of high resistance farther down the line. I'd look closely at the plugs and wires for signs of deterioration. Proper plug gap and dielectric grease for all connections, when used with quality wires, should allow even the cheapest cap and rotor last more than 3000 miles.

 

[Camo-5]

I did have a bad connection at the battery. Could the inconsistant current from the battery / alternator cause the fouling? I'm trying really hard to remember if I replaced the wires or the PO. They are quality 8.0mm wires and they look new.....that's the problem with working on too many automotive projects, I keep forgetting what was done to each! I do know the plugs were new, but I'll pull them and see if they are also fouled and check the gap. Thanks for the tip.

 

[Camo-5]

That was it. Cap and rotor fouled out after only 3000 or so miles. Not sure why other they were cheap - garbage parts. I replaced them with OEM equipment yesterday and what a huge difference today. I checked the plugs and they all looked fine. The wires didn't appear worn, but I'm going to replace them anyway just in case they were the cause for the fouling cap and rotor. Geez I like when fixes are this cheap and easy (although it would have been easy to find it right away)!

 

[Matthew Currie]

A bit of drift here, but I started developing a bit of battery weakness recently, and on a trip it finally got serious enough that I figured I'd better do something about it. So I bought a new battery. Took the old one out, and discovered that it appeareed to be the original battery. The Jeep is a '99, with 212 thousand miles on it.

 

[Camo-5]

WoW! That's an old battery. Guess you kinda have to replace it once you find that out....

Well, bad news for me. It happened again (the stuttering and popping). After 3 rounds trips to work and 180 miles on the way up to my cabin this weekend, it started again.

It ran perfect (pulled my trailer at 70mph for 180) for most of the way. I stopped to relieve myself at a rest stop, got back in, started it up and almost got smooshed by an 18 wheeler trying to merge when it started chugging. I figured out that manually shifting from 1-2, and then 3rd, I could keep the rpms up and accelerate to speed. Once at about 55mph, I could shift to D and it stopped. Drove it the rest of the weekend and all the way home (230 miles with 2 stops) and it didn't do it.

Starting to suspect an electical short or maybe the coil connections.....I'm gonna replace the coil and clean up the connections again...after that, new plug wires. At least I know how to get him home when it starts up again - if it starts up again.

Any new ideas? It's just really strange that it would do it and then stop all of a sudden. If it was a short, I would have thought it would take some 'jiggling' to get it to start / stop. I don't know......I hate these kinds of problems.....

 

[rpyne]

Have you checked to make sure your cat or muffler is not plugged? I've seen this with a couple of different vehicles I've had. It will idle fairly normal, but will chike and spit as RPM increases.

 

[Camo-5]

There is no cat (staight pipe), but I suppose it could be the muffler. Could this be an intermitent thing? Is it possible for the packing to shift and only cause it sometimes? I've been wanting a new muffler....this sounds like a good excuse!

 

[Rick Anderson]

Sorry, I didn't read the entire thread.

I had a friend with bad battery cables. The resistance checked fine, but the car would NOT crank after putting in a new battery and starter motor. Checking the resistance doesn't tell you the total current carrying capacity of the wire, and the battery cable do carry hundreds of amps during starting.

I've just posted on other threads I had a bad coil, I couldn't tell until I actually unbolted it and pulled it out and looked at it under good light. If your coil is mounted low on a bracket on the side of the motor and is tough to see/reach, it might be worth pulling it out and inspecting it closely under the light.

We finally confirmed bad cables by using jumper cables to bypass the battery cables to connect the battery to the starter and it cranked just fine.

Bottom line, bad battery cables, that check good with an ohm meter, you can tell they are bad by how strong the start is with a good battery and starter. I.E., if the the motor cranks just fine, then there probably isn't anything wrong with the battery cables.