For some reason lately when I put the key in to start up my 96 Cherokee Sport 4.0 4x4 it doesn't start, the battery isn't the issue, that I am certain of, I can turn it over a few times and nothing, usually it'll start up after several cranks. It doesn't make a sound, I can hear the fuel line whine so I hear that kick in, but again like I said it does not always seem to start.

I had to let it sit for a few hours and then go out and after about 4 attempts it started, another day after 5 or 6 attempts,

There is no sound, no click click click, or just a single click. Zero noise at all.

Is this most likely starter? ignition switch? or ignition coil? I buy oem parts per CCKen's recommendation years ago, and so far he's never mislead me paying the extra cost.

I believe the ignition switch was replaced 3 yrs ago and the ignition coil was replaced 2 yrs ago, the CPS was replaced 4 yrs ago....... I do not know that the starter was replaced, I don't see a receipt for it and I keep them all, so I don't think it's been replaced in the past 6 yrs I have had the Jeep.

What say you "geniuses"?

I'd appreciate any insight you can provide.

--Jessica

 

Try cycling key four or five time letting fuel pump run until it stops priming.
Then try and start.Sounds like check valve not holding.

 

What exactly is the check valve? so I know what to look up should I need to replace that

 

Once it's running does it stay running?

You can check if the fuel is losing pressure by checking it on the rail.

 

For the past month or so it's been dying at just about every stop light or stop sign sometimes right as I am pulling into my parking space, at about 5mph it will die as well. Never while cruising down the road though.

 

1. When you get NO sound, NO click, nothing; it's not a fuel issue. If it turns over and over and doesn't start, that can be fuel related. For the no start when you get no sound, no click, try wiggling the shift lever while turning the key or starting in neutral. If either of these strategies allows the engine to turn over, the problem is the "neutral safety switch".....a very common problem on the XJ. They can often be refurbished to restore function. Here is a link on performing that procedure. Good pics with it.

http://bc4x4.com/tech/2010/jeep-neut...ty-switch-nss/

2. Any check engine light ever observed? If so, you must retrieve codes for clues and guidance on how to proceed. In the absence of codes, The #1 cause of the Jeep 4.0 engine dying at idle is a marginal battery. And YES, you can have a battery that is strong enough to start the engine, but marginal enough to give the engine management system fits and cause stalling at idle. Have the battery "load tested" for free at any parts store. There certainly are other possibilities like cleaning the throttle body and idle air control, marginal fuel pressure (TEST IT!) fresh tuneup hardware, etc. but simple stuff first. Always.

 

My battery is one of the Gold series batteries from Advance Auto that I had put in less than 3 months ago. I had it tested about 3 weeks ago as well, because I am perplexed as my Jeep just seems to have these random issues every year. It's kind of nuts really, but I'll drive it through Hell and back before I get rid of it, unless she goes off a mountain top somewhere I wont get rid of her, and even then it's all about how far she falls off a mountain. lol

Also I have new battery cables as well as clamps, which my father did because he said let me put new ones in anyways. I didn't argue when I visited him. lol

I actually had an issue with the NSS when I first got the Jeep 6 yrs ago, I took everything apart, and never had an issue again....perhaps another 6 yrs it's time to do it again? lol

As for check engine lights, no. I don't get a code doing the key trick either, just the one saying I've disconnected the battery and end of codes.



Thanks for the info and suggestions.

 

Worth a shot. Follow the link I provided. Know though that "refurbishing" does NOT guarantee function of this switch. Sometimes it works, other times not and that is when it's time to replace it. Everything electrical is subject to failure. Also be aware that genuine MOPAR NSS switches can be kind of spendy, but are worth every penny as offshore ebay switches can be total crap. Start with spraying the fasteners with penetrating oil a number of times before you want to remove it. Those fasteners can be VERY difficult to remove.

 

A NSS will keep it from starting but won't shut it off.
I wonder if you have more than one problem.

 

She does.

 

Yeah I agree for sure on that. You know when you've got a problem, then you really know when you have more than one problem. sigh.

I am just confused as to what could be causing the stalling at stops; whether it be a stop light or stop sign or slowing down to pull into a parking space. I does it I'd say 90% of the time.

Would the air idle control valve have anything to do with it? I feel like it's vacuum-ish related, because it just began out of nowhere like things do and from the get go, when that issue first appeared it was bad and has remained bad. Its one of those things that didn't go from bad to worse, it has been dying 90% of the time at stops. I have to put the Jeep in neutral at stop lights then toss it back into drive so it won't die.

Would a bad starter cause the no sound? It just turns forward and has no clicks nothing.
Or does that sound more like the ignition switch? I don't have a problem replacing several things (preventative maintenance never hurts), but if it's possibly the CPS again or maybe something more sinister I'd love to replace em all. I plan on keeping it til she begs me to kill her off 5 decades from now. lol

I could list dozens of items I have replaced in the past 3 years on it. All with genuine mopar parts or original parts if possible, as I've noticed for the most part they work better than the slightly cheaper ones do. I will say that's difficult to get sometimes, but eh for me it's worth it in the end.

What would you suggest is most likely In Your Opinion, to be the most logical cause of the stalling issue I mentioned?

After I got home from work, I took the NSS off and cleaned it etc etc... put it back together, etc last night so that was a fun evening. Note: Wine isn't the best option when working on a Jeep. I have to get some Beer after work to give me more options.

 

1. Did cleaning the NSS make any difference in the no start? When a no-click no start occurs, it would be helpful to see if you have battery voltage directly AT the starter. With the ignition switch on, take a meter and test for voltage at the starter. Have you tried wiggling the shift lever and starting in neutral when you experience a no-click, no start? Very simple tests that can help isolate a flaky neutral safety switch.

2. For the stalling, I would #1. Clean the idle air control and throttle body and #2. TEST the throttle position sensor. More on these two items below.
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The Idle Air Control (IAC) is mounted on the back of the throttle body. (front for 87-90) The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is moved in, the air control passage flows more air which raises the idle speed. When the valve plunger is moved out, the air control passage flows less air which lowers the idle speed. Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea.

CLEANING THE JEEP 4.0 IDLE AIR CONTROL

Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a torx driver (2 bolts; one can be kind of hard to get to)

“Gently” wiggle out the IAC from the throttle body. Gasket on the IAC can be re-used if it is not damaged

Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and is best for this task. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.

Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner

It is also a good idea to clean the entire throttle body itself, the butterfly valve inside of the throttle body and all associated linkage as long as you have things disassembled

Reinstall IAC and check idle quality
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The throttle position sensor is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine how much fuel the engine needs. The TPS is really just a simple potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM. As you move the accelerator pedal with your foot, the output of the TPS changes. At a closed throttle position, the output of the TPS is low, about a half a volt. As the throttle valve opens, the output increases so that, at wide open throttle, the output voltage should be above 3.9 volts. Testing can be performed with an electrical meter. Analog meter is best. You are looking for a smooth sweep of voltage throughout the entire throttle band. While slowly opening and closing the throttle, take note to the movement of the voltmeter needle. There should be a direct relationship between the needle motion to the motion of the throttle. If at anytime the needle moves abruptly or inconsistently with the movement of the throttle, the TPS is bad

You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.

The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -

NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!

• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted accordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the denied acceptable range causing the ECU to incorrectly fuel the engine. This is noticeable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.

 

Cranking over several times b4 starting is no a NSS issue. Being a 1996 its the transition year. Check vale will be dfferent according to fuel pump location.

 

The next time you start either of your Jeeps when COLD, try the poor mans prime that I outlined.

It is a very simple but important test to help you determine root cause. You can have a fuel pump that passes the pressure test, but because of a bad check valve, it leaks down fuel pressure over time as the vehicle sits. I've seen it countless times.

Report your results.

 

Mine is in the fuel tank.

All the cleaning I did to the NSS changed nothing.

It stalls out 9/10 times and whenever I start to go, it always hesitates too, I'd say 7/10 times.. like its jerking forward and back. I'm sure you know what I mean here.

Is there a brand I should avoid when it comes to replacing the IAC and the TPS I only have a digital meter so I cannot test it.

I have replaced the IAC valve previously, just last year I believe and I believe I replaced the TPS as well, however we all know that means squat..... I will look into everything advised on Saturday.

Thanks so much for all the help and suggestions!