ratty Posted September 11, 2018 Share Posted September 11, 2018 Hello again. Recently I've been having an issue where my truck will die randomly when at idle. Doesn't happen all the time, and sometimes happens when I break quickly. The radio still works when its dead, it just stops. Power steering too. Edit: Forgot to mention, it has been idling weird too. Usually after I restart the car after it dies it will idle at 2000-3000 for a little while. It's an 88 auto 4.0. Thanks. Link to comment Share on other sites More sharing options...
cruiser54 Posted September 11, 2018 Share Posted September 11, 2018 Ever do this? 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 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. Link to comment Share on other sites More sharing options...
ratty Posted September 11, 2018 Author Share Posted September 11, 2018 2 hours ago, cruiser54 said: Ever do this? 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 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. Thanks! I have replaced the IAC already. About 4 months ago. The throttle was looking pretty good then too. I’ll re check it though. Anyway to test the IAC sensor? Also, do you think a bad EGR would do anything I described? Link to comment Share on other sites More sharing options...
SVPete Posted September 12, 2018 Share Posted September 12, 2018 When it dies, will the truck re-start right away or does it have to sit a while (or crank it a long time before it will start like it is flooded)? Link to comment Share on other sites More sharing options...
ratty Posted September 12, 2018 Author Share Posted September 12, 2018 20 minutes ago, SVPete said: When it dies, will the truck re-start right away or does it have to sit a while (or crank it a long time before it will start like it is flooded)? It starts right back up. Link to comment Share on other sites More sharing options...
SVPete Posted September 12, 2018 Share Posted September 12, 2018 I would certainly follow Cruiser's advice and do a good cleaning of the IAC and the throttle body passages first. Can a bad EGR valve or EGR transducer (which comes with a new EGR valve, the more likely culprit between the two in my opinion) cause this type of problem? In my opinion, yes on the stalling, no on the high revs on start up. As a test, you can disconnect the vacuum line to the EGR solenoid and plug it with a golf tee to eliminate vacuum which activates the EGR. The solenoid is located on the drivers side fender near the air cleaner. You want to disconnect and plug the elbow connection, not the funky one with a filter on it. If your stalling issue goes away, then you have narrowed the shot-group. Link to comment Share on other sites More sharing options...
ratty Posted September 12, 2018 Author Share Posted September 12, 2018 17 minutes ago, SVPete said: I would certainly follow Cruiser's advice and do a good cleaning of the IAC and the throttle body passages first. Can a bad EGR valve or EGR transducer (which comes with a new EGR valve, the more likely culprit between the two in my opinion) cause this type of problem? In my opinion, yes on the stalling, no on the high revs on start up. As a test, you can disconnect the vacuum line to the EGR solenoid and plug it with a golf tee to eliminate vacuum which activates the EGR. The solenoid is located on the drivers side fender near the air cleaner. You want to disconnect and plug the elbow connection, not the funky one with a filter on it. If your stalling issue goes away, then you have narrowed the shot-group. Great info. Thank you! Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 30, 2020 Share Posted March 30, 2020 Instead of starting a new thread, I decided to add to this one as it is right in line with what I found to be my stalling issues. One of the things that can be so frustrating about these trucks is that there's never just 1 or 2 possible reasons for certain issues, it always seems like there's 5, 6 or even more potential causes for a performance problem. Anyhoo, I used the search function to read several different threads about stalling issues. The symptoms on this thread were basically identical to mine; truck would start no problem, sometimes would go to high idle, then more so lately once up to temp it would just stall at idle or when lifting on the throttle for more than a few seconds, which I had never experienced before. Under power/acceleration, no issues, would run fine with no real hiccups. So here is what I have identified and done to solve the problem: Background Have done Cruiser's tips 1, 3, 4, 8*, 11, 31 PO had removed 3 prong connector on TPS and hardwired the wires, so no way to test TPS Recently installed bored TB from MeanLemons, cleaned IAC at that time Had recently installed Bosch 746 injectors New front/left vacuum lines Troubleshooting Cut hardwiring to TPS and wired in 3 prong male plug to new Mopar TPS, adjusted to proper setting; better idle initially, then stalling when warmed up Visual inspection of vacuum lines for cracks/leaks; appeared to be leak around base of EGR valve at block Changed out EGR valve with used (but confirmed operational) unit from Cruiser, cleaned surface area & added high temp Permatex; no real change Opened EGR transducer for inspection, no tears in rubber diaphragm observed, put diaphragm back together Also had bought used replacement EGR solenoid and transducer from Cruiser, both OEM, for potential swap out As recommended in this thread, removed elbow connection vacuum line from EGR solenoid, started and idled no problem Re-attach elbow connection vacuum line to EGR solenoid and immediately stalls Swap out EGR solenoid for used replacement, same results, elbow connection removed idles fine, attach elbow connection and it stalls immediately Swap out EGR transducer for used replacement, idles smooth with elbow connection removed, NO STALL when attaching elbow connection Re-open original EGR transducer, remove rubber diaphragm, observe vacuum hole under diaphragm clogged with carbon/oil Clean original EGR transducer plastic top and vacuum hole with carb cleaner, also cleaned out bottom plastic part of transducer . I did NOT clean rubber diaphragm with anything, fearful carb cleaner might eat through it or trying to wipe it might tear it. Put transducer back together. Re-installed original EGR transducer, started and idled fine with elbow connection removed, reattached elbow connection vacuum line to EGR solenoid, DID NOT STALL and idles excellent, better than it has in quite some time! Pictures show the 3 parts to the transducer: top, rubber diaphragm, bottom in that order from left to right. So long story short, this seems like it could be a common culprit to idling and stalling issues, and fortunately can be an easy fix. FYI, if you take apart your transducer be very gentle when doing so, you don't want to potentially tear the diaphragm or break off one of the tabs on the bottom piece that clamps the housing together. These are not sold anymore and EGR valves themselves seem to have been discontinued for the Renix era 4.0L. For now, I've got 2 good EGR valves and transducers so hopefully I'm good for awhile. Link to comment Share on other sites More sharing options...
omega_rugal Posted March 30, 2020 Share Posted March 30, 2020 leaky injectors? Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 30, 2020 Share Posted March 30, 2020 17 minutes ago, omega_rugal said: leaky injectors? ???!!!! I just explained what the issue was........clogged EGR transducer. Injectors are fine. Link to comment Share on other sites More sharing options...
omega_rugal Posted March 30, 2020 Share Posted March 30, 2020 i got lost in that text wall... Link to comment Share on other sites More sharing options...
cruiser54 Posted March 30, 2020 Share Posted March 30, 2020 Text wall? What's that? That was the most simple, factual, chronological explanation, With photos and numbers. I don't get it. Link to comment Share on other sites More sharing options...
1989commanche Posted March 30, 2020 Share Posted March 30, 2020 9 hours ago, cruiser54 said: Text wall? What's that? That was the most simple, factual, chronological explanation, With photos and numbers. I don't get it. Some people don’t want to take the time to read stuff. Just want the cliffs notes version. Link to comment Share on other sites More sharing options...
cruiser54 Posted March 30, 2020 Share Posted March 30, 2020 We should wait til it comes out on video then? Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 31, 2020 Share Posted March 31, 2020 2 hours ago, cruiser54 said: We should wait til it comes out on video then? Link to comment Share on other sites More sharing options...
SVPete Posted March 31, 2020 Share Posted March 31, 2020 The spring was intact in the original transducer? Mine was rusted away to dust. Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 31, 2020 Share Posted March 31, 2020 58 minutes ago, SVPete said: The spring was intact in the original transducer? Mine was rusted away to dust. Yup, was in good shape Link to comment Share on other sites More sharing options...
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