I have a 97 TJ 4.0 manual transmission with 77k that I’m having starting issues with. The Jeep sits for periods of a week and sometimes two weeks. It was starting intermittently about 6 months ago so I had it towed to my mechanic. He said it didn’t start one time and he held the gas petal down just a little and it fired right up and started fine for a couple more days. He couldn’t find anything wrong with it and said he looked on the forums and several people were saying the battery was the issue for them. I got it home and tried to start it the next day and it wouldn’t start. I replaced the battery about 5 months ago and it’s worked fine till now. Now when it’s cold or been sitting for about 30 minutes or more it won’t start. It sat for ten days and wouldn’t start. It cranks really strong but won’t start. I jumped it and drove to the autoparts store less that two miles away and had the battery and alternator checked. The alternator was good and the battery was strong with good cold cranking amps. I didn’t get a printout but I think he said 12.7 and 800. After he was done it fired right up and did so about 5 more times. Then it sat for about thirty minutes and wouldn’t start for the first few times I tried but ended up starting on the 3rd or 4th try. After that it sat for 40 minutes and wouldn’t start. Any help would be greatly appreciated. Thanks.
97 TJ Starting Issue
- Thread starter Nsbbum
- Start date
No idea if this is your problem, but I occasionally have intermittent start problems and it is ALWAYS solved by cleaning the TPS. For me, the tell tale sign is a long crank before it finally starts, and needing to feather the gas to keep it alive once it does start. There's a full-on cleaning procedure written up in the how-to section. I really ought to follow the steps.
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So it will always start with a jump? And after 10-15 minutes of sitting it will start up? But after 30 or more minutes it wont start, but it will with a jump?
Next time you have it running for a bit and shut it off, disconnect the negative battery cable. Hook it back up the next day and see if will start. Maybe something is draining your battery while it sits?
Next time you have it running for a bit and shut it off, disconnect the negative battery cable. Hook it back up the next day and see if will start. Maybe something is draining your battery while it sits?
Yes it will start every time with a jump. It starts every time after being jumped as long as it’s not more than about 30 minutes or more of the engine being off. After being jumped I can shut the engine off after a minute and it will restart again without a jump. I don’t think anything is draining the battery because it sat for 10 days or more and the battery tested good with driving it less than 2 miles. Before replacing the battery it would start with giving it a little gas and would sometimes require a little feathering. Once I replaced the battery 5 months ago all those problems went away and it started normally without touching the gas and idled normally every time without feathering. Thanks for the replies.
My 95 S10 had similar problems this fall, which ended up being due to a failing fuel pump. I have never had a fuel line issue on my jeep, but I wonder if it could be a fuel thing. I think the truck's motor required a certain psi at the injectors in order to ignite, but could stay running with a lower psi.
That's interesting, but even if true, I'm not seeing how jump-starting would provide a higher PSI? The OP's Jeep will start if jumped.
The battery testing good after even a few miles of driving just tells you your alternator is good and the battery is able to hold the charge.
I am about 100% certain you have something draining your battery. As @DaYooperTransplant mentioned, unplug your negative cable, wait an hour, connect the terminal and try to start it.
My money is on that it will start with no issues after this test.
Your real task is going to hunt down what is draining your battery.
If you search around this forum there are a lot of topics on grounds. I would start there and remove each ground, clean both mating areas up real good and then re-attach. Inspect your battery cables.
There are also a lot of threads on here that discuss parasitic battery drain. Google has a lot too. If you have a decent multimeter, you can check it yourself in your garage. It's very possible there is something draining your battery with the key off and parked. Radio, faulty relay, under hood light, bad diode etc,.
Keep us posted
There are also a lot of threads on here that discuss parasitic battery drain. Google has a lot too. If you have a decent multimeter, you can check it yourself in your garage. It's very possible there is something draining your battery with the key off and parked. Radio, faulty relay, under hood light, bad diode etc,.
Keep us posted
Thanks for all the replies guys. I’m away from the Jeep till Monday but I will try these suggestions then.
I just tried jumping it so I could disconnect the negative cable to see if that is the problem. Now it won’t start even with a jump, A neighbor who is a mechanic said the problem is the ecu is not getting power and that’s where I need to start. The check engine light is not coming on when you turn the ignition switch on and his code scanner would not connect either. Prior to these problems the chech engine light was always on while driving because there was a code on from one of the o2 sensors I believe. My mechanic said not to worry about it and that it wouldn’t hurt anything. I noticed the last few times I drove it the check engine light wasn’t on either. My neighbor said he didn’t think it was the bulb since his scanner wouldn’t hook up to it. Any ideas now?
Easy check, use a multimeter, to check your battery voltage, on DC. What is it, my guess its way below 12volts?
The OBDII reader won't work if there isn't enough of a charge in the battery.
The reason the check engine light turned off is probably due to the battery discharging and your codes getting erased, I wouldn't worry about that right now, until you get it started again.
Once you get it started you will likely find the O2 sensor as a pending code.
You probably discharged your battery quite a bit and need to give it more time to charge up via jump, or pull the battery and charge it.
The OBDII reader won't work if there isn't enough of a charge in the battery.
The reason the check engine light turned off is probably due to the battery discharging and your codes getting erased, I wouldn't worry about that right now, until you get it started again.
Once you get it started you will likely find the O2 sensor as a pending code.
You probably discharged your battery quite a bit and need to give it more time to charge up via jump, or pull the battery and charge it.
One other item, if your battery discharges way below starting voltage in 30 minutes, a whole weekend of discharging probably severely trained your battery.
The battery voltage is 12.68 after sitting for 6 days. The Jeep can not be jumpstarted anymore and all lights come on when turning the ignition switch to on except the check engine light which I believe should come on prior to starting the engine whether or not you have any current codes.
had a car years ago did the same thing. i could jump it and drive it all day. turn it off overnight and nothing. ended up being a short in the alternator windings.
What specifically isn't happening when you tried to jump it? Does it turn over? Does the starter solenoid click? Does it fire but not catch? Or do you literally get nothing when you turn the key?
It turns over strong but doesn’t start and will do that without having a jump hooked up to it as well. All seems normal when turning key except check engine light doesn‘t come on prior to going to start.
the CEL should definitely come on for a few seconds when you start the jeep, or even when you turn it ON regardless of any codes present. I just went through this exact thing, turns out my CEL was burned out and I suspect yours is as well. It's a "74" bulb when you go to replace it.
Weird one, not totally sure what to recommend next, I would have lost my money on that bet.
A few questions that might spark a troubleshooting path...
Did you perform any work prior to this issue coming up?
Any other symptoms prior to this happening?
Have you checked basics like battery cable tight and well attached?
If you use the key trick to get codes, do any come-up?
A few questions that might spark a troubleshooting path...
Did you perform any work prior to this issue coming up?
Any other symptoms prior to this happening?
Have you checked basics like battery cable tight and well attached?
If you use the key trick to get codes, do any come-up?