Jeep stalls at idle
07-24-2018, 01:21 PM
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Model: Cherokee (XJ)
Jeep stalls at idle
My wife has a 99 jeep cherokee 4.0 4wd. Seems to run great but when coming to a stop the jeeps rpm drop causing to idle rough then it shuts off and I have to wait a few minutes to restart it or it just cranks. Anyone have this issue before? I've changed the brake booster, TPS sensor, checked fuel pressure and just picked up the TCC sensor but haven't installed it yet. I also disconnected the Cam position sensor and got nothing. No check engine light on or stored codes of Any kind. Any advice would be appreciated.
Last edited by Airborneivan; 07-24-2018 at 02:03 PM. Reason: Adding information
07-24-2018, 01:45 PM
#2
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Is the check engine light illuminated?
If you quickly shift into Neutral when this begins to happen does the behavior change?
Typically, the first place to look for dying at idle is the Idle Air Controller (IAC) / Throttle Body. The IAC is like a little version of your foot on the gas pedal, and is responsible for allowing the computer to managed the idle RPM by allowing varying amounts of air into the throttle body, even though your foot is off of the accelerator. It can fail, or get gummed up and stick. If feathering the accelerator pedal (lightly depressing) helps to get the motor started, or keeps it from dying during idle conditions, this is also a sign that the IAC is not doing its job properly.
If you quickly shift into Neutral when this begins to happen does the behavior change?
Typically, the first place to look for dying at idle is the Idle Air Controller (IAC) / Throttle Body. The IAC is like a little version of your foot on the gas pedal, and is responsible for allowing the computer to managed the idle RPM by allowing varying amounts of air into the throttle body, even though your foot is off of the accelerator. It can fail, or get gummed up and stick. If feathering the accelerator pedal (lightly depressing) helps to get the motor started, or keeps it from dying during idle conditions, this is also a sign that the IAC is not doing its job properly.
07-24-2018, 02:05 PM
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My wife has a 99 jeep cherokee 4.0 4wd. Seems to run great but when coming to a stop the jeeps rpm drop causing to idle rough then it shuts off and I have to wait a few minutes to restart it or it just cranks. Anyone have this issue before? I've changed the brake booster, TPS sensor, checked fuel pressure and just picked up the TCC sensor but haven't installed it yet. I also disconnected the Cam position sensor and got nothing. No check engine light on or stored codes of Any kind. Any advice would be appreciated.
Is the check engine light illuminated?
If you quickly shift into Neutral when this begins to happen does the behavior change?
Typically, the first place to look for dying at idle is the Idle Air Controller (IAC) / Throttle Body. The IAC is like a little version of your foot on the gas pedal, and is responsible for allowing the computer to managed the idle RPM by allowing varying amounts of air into the throttle body, even though your foot is off of the accelerator. It can fail, or get gummed up and stick. If feathering the accelerator pedal (lightly depressing) helps to get the motor started, or keeps it from dying during idle conditions, this is also a sign that the IAC is not doing its job properly.
If you quickly shift into Neutral when this begins to happen does the behavior change?
Typically, the first place to look for dying at idle is the Idle Air Controller (IAC) / Throttle Body. The IAC is like a little version of your foot on the gas pedal, and is responsible for allowing the computer to managed the idle RPM by allowing varying amounts of air into the throttle body, even though your foot is off of the accelerator. It can fail, or get gummed up and stick. If feathering the accelerator pedal (lightly depressing) helps to get the motor started, or keeps it from dying during idle conditions, this is also a sign that the IAC is not doing its job properly.
07-24-2018, 05:41 PM
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Year: 1999
Model: Cherokee
Engine: 4.0
One of the #1 causes of stalling only at idle is a marginal battery.
And yes, you absolutely CAN have a battery that is strong enough to start the engine but marginal enough to give the engine management system fits. I can't remember how many times I have seen this and resolved it.
Have your battery "load tested" at any parts store for free. Not saying that is your problem, but it sure is something that needs to be ruled in or out early in the troubleshooting process.
Good luck and keep us updated!
And yes, you absolutely CAN have a battery that is strong enough to start the engine but marginal enough to give the engine management system fits. I can't remember how many times I have seen this and resolved it.
Have your battery "load tested" at any parts store for free. Not saying that is your problem, but it sure is something that needs to be ruled in or out early in the troubleshooting process.
Good luck and keep us updated!
08-21-2018, 07:32 PM
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Year: 2001
Model: Cherokee (XJ)
Engine: 4.0L
Similar issue in my 2001. Jeep runs and drives without any issue, but it will stall if I come to a stop (regardless if in park, neutral, drive, or reverse). I find myself popping it into neutral at a red light to give it just the slightest amount of throttle input to keep it alive. If I don't give it any of the skinny pedal (I try to hover around 1,000-1,100 RPM), it will die. I can immediately crank it back up without issue, but it will not keep an idle. Not a rough idle and sputtering out or hunting for an idle or anything, it just falls to zero.
No CEL or anything giving indication of a problem.
I had a bad fuel cap and thought maybe there was a vacuum issue. Changed out the cap and it started up and idled without fault. Great! Took it around the block, and once it got up to temperature it started doing it all over again.
This was my next thought, but with no CEL, is this correct? What can I do to test it before I toss parts at it? Is it similar to an MAF I've experienced on other vehicles where you can clean it up and be ready to go? I don't know how, but Rock Auto has THIS ONE for $7.64. May be worth it to just go ahead and pick one up regardless if it's that cheap.
Thanks in advance!
No CEL or anything giving indication of a problem.
I had a bad fuel cap and thought maybe there was a vacuum issue. Changed out the cap and it started up and idled without fault. Great! Took it around the block, and once it got up to temperature it started doing it all over again.
Is the check engine light illuminated?
If you quickly shift into Neutral when this begins to happen does the behavior change?
Typically, the first place to look for dying at idle is the Idle Air Controller (IAC) / Throttle Body. The IAC is like a little version of your foot on the gas pedal, and is responsible for allowing the computer to managed the idle RPM by allowing varying amounts of air into the throttle body, even though your foot is off of the accelerator. It can fail, or get gummed up and stick. If feathering the accelerator pedal (lightly depressing) helps to get the motor started, or keeps it from dying during idle conditions, this is also a sign that the IAC is not doing its job properly.
If you quickly shift into Neutral when this begins to happen does the behavior change?
Typically, the first place to look for dying at idle is the Idle Air Controller (IAC) / Throttle Body. The IAC is like a little version of your foot on the gas pedal, and is responsible for allowing the computer to managed the idle RPM by allowing varying amounts of air into the throttle body, even though your foot is off of the accelerator. It can fail, or get gummed up and stick. If feathering the accelerator pedal (lightly depressing) helps to get the motor started, or keeps it from dying during idle conditions, this is also a sign that the IAC is not doing its job properly.
Thanks in advance!
Last edited by spazzyfry123; 08-21-2018 at 07:41 PM.
08-22-2018, 07:52 AM
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Originally by TJWalker of CherokeeForum & JeepForum
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 retracted, the air control passage flows more air which raises the idle speed. When the valve plunger is extended, 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. This should be part of a normal tune-up procedure and whenever idle/stalling issues are present.
CLEANING THE JEEP 4.0 IDLE AIR CONTROL
Revised 1-31-2016
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 retracted, the air control passage flows more air which raises the idle speed. When the valve plunger is extended, 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. This should be part of a normal tune-up procedure and whenever idle/stalling issues are present.
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). On ’91 and later, it may be easier to just remove the whole throttle body. Be sure to use a new throttle body to manifold gasket when reinstalling.
- “Gently” wiggle out the IAC from the throttle body. Gasket/O-ring 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 oxygen sensors. 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 bore itself, the butterfly valve inside of the throttle body and it’s edges, and all associated linkage as long as you have things disassembled.
Revised 1-31-2016
08-23-2018, 07:07 PM
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Year: 2001
Model: Cherokee (XJ)
Engine: 4.0L
Originally by TJWalker of CherokeeForum & JeepForum
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 retracted, the air control passage flows more air which raises the idle speed. When the valve plunger is extended, 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. This should be part of a normal tune-up procedure and whenever idle/stalling issues are present.
CLEANING THE JEEP 4.0 IDLE AIR CONTROL
Revised 1-31-2016
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 retracted, the air control passage flows more air which raises the idle speed. When the valve plunger is extended, 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. This should be part of a normal tune-up procedure and whenever idle/stalling issues are present.
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). On ’91 and later, it may be easier to just remove the whole throttle body. Be sure to use a new throttle body to manifold gasket when reinstalling.
- “Gently” wiggle out the IAC from the throttle body. Gasket/O-ring 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 oxygen sensors. 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 bore itself, the butterfly valve inside of the throttle body and it’s edges, and all associated linkage as long as you have things disassembled.
Revised 1-31-2016
Fired right up and idled without issue. I let it get to about 180°-ish with the idle still humming along at about 750 RPM. I popped it into neutral to back out of the garage to give it a test run and it fell down to maybe 200 RPM (didn't stall!). I tossed it into neutral, drive, park...it didn't matter; the idle was glued to about 200-300 RPM. I could rev it up and it would be fine, but just fall back down. I didn't want to risk taking it for a drive and it stalling on the roads.
So... I don't know if it actually got any better after cleaning out the sensor and throttle body very thoroughly , but it seems odd that it will idle fine (and drive fine as it seems) until it approaches operating temperature. Could this have something to do with emissions? Or since it didn't just completely stall on me after cleaning, is that a sign of improvement and my IAC is just hanging on by a thread?
Thanks again for everyone's help! Gotta love the community.
-Tyler
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08-23-2018, 07:09 PM
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Year: 1990
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Thanks for the walk through! I just performed all of this and look to be in the same situation. It was a little carbonized (nowhere near as bad as the first and second pictures), but I cleaned everything up and slapped it back together.
Fired right up and idled without issue. I let it get to about 180°-ish with the idle still humming along at about 750 RPM. I popped it into neutral to back out of the garage to give it a test run and it fell down to maybe 200 RPM (didn't stall!). I tossed it into neutral, drive, park...it didn't matter; the idle was glued to about 200-300 RPM. I could rev it up and it would be fine, but just fall back down. I didn't want to risk taking it for a drive and it stalling on the roads.
So... I don't know if it actually got any better after cleaning out the sensor and throttle body very thoroughly , but it seems odd that it will idle fine (and drive fine as it seems) until it approaches operating temperature. Could this have something to do with emissions? Or since it didn't just completely stall on me after cleaning, is that a sign of improvement and my IAC is just hanging on by a thread?
Thanks again for everyone's help! Gotta love the community.
-Tyler
Fired right up and idled without issue. I let it get to about 180°-ish with the idle still humming along at about 750 RPM. I popped it into neutral to back out of the garage to give it a test run and it fell down to maybe 200 RPM (didn't stall!). I tossed it into neutral, drive, park...it didn't matter; the idle was glued to about 200-300 RPM. I could rev it up and it would be fine, but just fall back down. I didn't want to risk taking it for a drive and it stalling on the roads.
So... I don't know if it actually got any better after cleaning out the sensor and throttle body very thoroughly , but it seems odd that it will idle fine (and drive fine as it seems) until it approaches operating temperature. Could this have something to do with emissions? Or since it didn't just completely stall on me after cleaning, is that a sign of improvement and my IAC is just hanging on by a thread?
Thanks again for everyone's help! Gotta love the community.
-Tyler
09-04-2018, 12:18 PM
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Year: 2001
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Took me about 20 miles of driving a few start/stop cycles before it finally seemed to make a difference. All seems good now.
I'm going to go ahead and purchase another one to keep on the shelf the next time it starts acting up I'll just go ahead and replace.
Thanks again!
I'm going to go ahead and purchase another one to keep on the shelf the next time it starts acting up I'll just go ahead and replace.
Thanks again!
09-04-2018, 01:04 PM
#10
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Great news. Thanks for reporting back.
07-10-2021, 07:51 AM
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