Base Idle Reset

Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
1,260
690
143
I'd like to post this for all the newer mustang owners and the others like me that never took the base idle reset seriously. I've had multiple engines and various setups but never once done the base idle reset. I just replaced the lifters in my car after having one collapse. I thought the bottom end had come apart because of the violent knocking coming from it.
So I did what some of us typically do. I turned a two day protect into a couple week extended project. There's a few rules in my projects. Never put fasteners back in without wire brushing them. This helps them go back in smoothly. Clean out the holes they came out of. Clean surfaces where gaskets go until you are tired of cleaning them.... then clean them one more time. Paint or repaint anything that's removed if possible. If not... clean clean clean. Dielectric grease every time. Anti seize everywhere applicable. Before reassembly check everything several times. Don't put off doing things till later because half the time that thing will cause you problems right off the bat.
So base idle reset. Just for the fun of it I watched every video I could find on this. I also read all the step by step posts I could find. I pasted every one of these texts into separate documents. So what did I find? All of them left out at least one step. The omits were random. As in they all left out something different. All of them. Some meant to leave it out I guess and some might have assumed you'd just do it. I'd rather have every single step and I'll decide if I want to skip steps.
These step need to be done in a specific order for a reason.
Results: my car doesn't stall every time I stop for the first time in years. The idle is perfect. You can just tell things are set correctly.
The other thing I remembered is that I like this car much better if it's not my daily driver. I bought it new and have been driving it since 1988. It's been back and forth as primary and occasional. It's about 1k miles from having 400k on it.
Anyway, do yourself a favor and do the reset!
 
  • Like
Reactions: 2 users
  • Sponsors (?)


Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
1,260
690
143
So how does the 'base idle reset' in the 'surging idle checklist' stack up?
Is it complete?
If not can you give us a break down of the complete procedure?
It's included in the has something missing crowd. I'm gonna type it all out at some point. I'm just hoping i don't miss a step.... :rlaugh:
Brew2L's video is actually very good and easy to follow. He made a new video recently and said he forgot to include one thing in that old vid so you'd have to watch both to get all of it.
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,513
2,853
234
It's included in the has something missing crowd. I'm gonna type it all out at some point. I'm just hoping i don't miss a step.... :rlaugh:
Brew2L's video is actually very good and easy to follow. He made a new video recently and said he forgot to include one thing in that old vid so you'd have to watch both to get all of it.
Since I am the guy who created the Surging Idle Checklist, I would be very interested ion seeing what you felt was an omission.
 
  • Like
  • PlusOne
Reactions: 3 users

Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
1,260
690
143
Since I am the guy who created the Surging Idle Checklist, I would be very interested ion seeing what you felt was an omission.
@jrichker I know you created it. I've been here for a long time. Your info is excellent. As i said though, if you go thru all the write-ups that i found and then a couple vids, they all vary. That's odd since this particular process needs to go in an exact order to give the computer the proper reset info. And I'm only referring to the base idle reset part.
I'm gonna write the process out when i can. It's not to replace yours. It's to take all them and make one list in order with all the steps no matter how small.
 

vrm71

Member
Dec 13, 2017
41
8
18
I don't understand the purpose of your post if you don't tell what the missing step is? You took the time to go through all the posts and vids on the subject to then post on here that somethings missing and you'll maybe, sometime get around to letting everyone know?
 

Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
1,260
690
143
I have a terminally ill family member that I take care of 24/7. Been going on for a year this month. I have hit and miss times to do every aspect of my life. I had to get my car running and was happy I did. I was encouraging others to do the reset. When I have time I will sit and go thru all this stuff and post it.

EDIT: Self removed the snappy parts of my response. I don't want this place to turn into The [email protected]&&@/_ ;)
 
Last edited:
  • Surprised
Reactions: 1 user

Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
1,260
690
143
Ok, I'm going to just post this and be done with the base idle reset deal.
If you are just learning and look around for instructions on this, it's not clear. For example, if I'm looking for instructions or a YouTube vid on installing an intake, I'm not going to watch a video on rebuilding an entire engine. If I want to use that person's instructions, I'd obviously skip to the intake part. Why in the world would I go thru the rest?
Like I stated above, @jrichker contributions to this site are excellent and appreciated. Nothing I do comes close to his detail. When I was doing my research on this months ago, all I could find was the "surging idle checklist." Down below all that stuff was one post on the base idle reset. Like I said, if you are just doing the reset then why would you go thru all the rest....You won't. So I'm pasting that text here:

-------paste-----
""""From stangnet... surging idle checklist:

OK, now you have gone through the list and eliminated most of the possible problems. Now your mechanical and electronic problems are fixed, you can set the base idle speed.

Setting the base idle speed:
First of all, the idle needs to be adjusted to where the speed is at or below 600 RPM with the IAC disconnected. If you have a wild cam, you may have to raise this figure 100-150 RPM or so. Then the electrical signal through the IAC can vary the airflow through it under computer control. Remember that the IAC can only add air to increase the base idle speed set by the mechanical adjustment. The 600 RPM base idle speed is what you have after the mechanical adjustment. The IAC increases that speed by supplying more air under computer control to raise the RPM’s to 650-725 RPM’s. This figure will increase if you have a wild cam, and may end up between 800-950 RPM

Remember that changing the mechanical idle speed adjustment changes the TPS setting too.

This isn't the method Ford uses, but it does work. Do not attempt to set the idle speed until you have fixed all the codes and are sure that there are no vacuum leaks.

Warm the engine up to operating temperature, place the transmission in neutral, and set the parking brake. Turn off lights, A/C, all unnecessary electrical loads. Disconnect the IAC electrical connector. Remove the SPOUT plug. This will lock the ignition timing so that the computer won't change the spark advance, which changes the idle speed. Note the engine RPM: use the mechanical adjustment screw under the throttle body to raise or lower the RPM until you get the 600 RPM mark +/- 25 RPM. A wild cam may make it necessary to increase the 600 RPM figure to 700 RPM or possibly a little more to get a stable idle speed.
Changing the mechanical adjustment changes the TPS, so you will need to set it.

When you are satisfied with the results, turn off the engine, and re-install the SPOUT and reconnect the IAC. The engine should idle with the range of 650-750 RPM without the A/C on or extra electrical loads. A wild cam may make this figure somewhat higher.

An engine that whose idle speed cannot be set at 600 RPM with the IAC disconnected has mechanical problems. Vacuum leaks are the #1 suspect in this case. A vacuum gauge will help pinpoint both vacuum leaks and improperly adjusted valves. A sticking valve or one adjusted too tight will cause low vacuum and a 5"-8" sweep every time the bad cylinder comes up on compression stroke. An extreme cam can make the 600 RPM set point difficult to set. Contact your cam supplier or manufacturer to get information on idle speed and quality""""
-------paste-----

In addition to this, I found Brew2L's base idle reset video. He actually made another video a full year later and mentioned that he left out something in the base idle vid. You would have never known to look there though unless you were just keeping up with him. He also added a note in the description of another item he skipped past. So there's that. Having said that, his video is by far the most detailed and walks you thru almost every single step.
You could use @jrichker post and the Brew2L video and get it done. Or you could guess at a couple things. My point in all this was to say that at no time did I find any one post, video or otherwise that had everything.
I intended to sit and write it all out while sitting in the car. As I mentioned above, unexpected family stuff got in the way.

So let's go......

Before you start:
-Make sure your distributor will allow full movement to adjust timing. Things could move once you actually set everything correctly. My TFI hit the thermostat protrusion of the lower intake and would only go to 6 or 7 degrees. If I stabbed it the other way it was useless. So guess what. This meant I had compensated for the low timing and low idle with the throttle blade stop. This also meant that once I set timing properly, everything else was off a decent amount. I had to clearance the corner of the TFI module in order to get total adjustability. You can't know these things unless you go ahead and set the timing.
-Car out of gear, e brake on, timing light set up, multimeter ready for the TPS adjustment, all necessary tools ready.

Now do the process.
1. Warm the engine up to normal operating temperature.
2. Turn all accessories off. Lights, radio, hvac, etc.
3. Unplug the IAC electrical connector.
4. Remove the spout plug at the distributor connection.
5. Start the engine.
6. Idle the car to 600-650rpm using the throttle blade stop.
7. Turn the engine off but leave the key in the on position.
8. At this point you can set the TPS. (I'm not getting into the TPS setting debate. Put it on .9 anything and it's fine.)
9. Turn off the ignition and reconnect the IAC electrical connector and plug the spout plug back in.
10. Disconnect the negative battery terminal!!!! Let the car sit for at least 30 minutes.
11. Reconnect the battery.
12. You should still have all electrical accessories off. Start the car and let it run for 2 minutes. You should see the computer make adjustments. Time this with your phone or watch. Don't guess at it.
13. Turn the car off for 2 minutes.
14. Now turn the HVAC blower motor to high. Turn the A/C to Max. Turn the headlights on. Turn the radio on. 70's or 80's stations give the best results!
15. Start the car and let it run for two minutes. Don't guess at the time.
16. Turn the car off.
You should now have the base idle reset done and your car hopefully won't stall every time you stop. It should have better manners across the board.

This should clear up -- when to plug the spout connector back in, when to disconnect the battery, and how long to wait for the computer to make adjustments, and the process of starting the car once with all accessories off then again with all on.

Hope this complete list can make it in a spot just for base idle reset only. It's sole purpose is to help folks.

I pecked all this out on my phone so I'll proof it all next time I'm online with my laptop.
 
  • Like
Reactions: 2 users

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
23,729
8,771
203
Thanks for that write up. I should enlist some help to ensure this gets into the 5.0 tech forum.
Hope all is as well as can be with everybody on your side of the fence.
 
  • Like
Reactions: 1 user

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,513
2,853
234
Ok, I'm going to just post this and be done with the base idle reset deal.
If you are just learning and look around for instructions on this, it's not clear. For example, if I'm looking for instructions or a YouTube vid on installing an intake, I'm not going to watch a video on rebuilding an entire engine. If I want to use that person's instructions, I'd obviously skip to the intake part. Why in the world would I go thru the rest?
Like I stated above, @jrichker contributions to this site are excellent and appreciated. Nothing I do comes close to his detail. When I was doing my research on this months ago, all I could find was the "surging idle checklist." Down below all that stuff was one post on the base idle reset. Like I said, if you are just doing the reset then why would you go thru all the rest....You won't. So I'm pasting that text here:

-------paste-----
""""From stangnet... surging idle checklist:

OK, now you have gone through the list and eliminated most of the possible problems. Now your mechanical and electronic problems are fixed, you can set the base idle speed.

Setting the base idle speed:
First of all, the idle needs to be adjusted to where the speed is at or below 600 RPM with the IAC disconnected. If you have a wild cam, you may have to raise this figure 100-150 RPM or so. Then the electrical signal through the IAC can vary the airflow through it under computer control. Remember that the IAC can only add air to increase the base idle speed set by the mechanical adjustment. The 600 RPM base idle speed is what you have after the mechanical adjustment. The IAC increases that speed by supplying more air under computer control to raise the RPM’s to 650-725 RPM’s. This figure will increase if you have a wild cam, and may end up between 800-950 RPM

Remember that changing the mechanical idle speed adjustment changes the TPS setting too.

This isn't the method Ford uses, but it does work. Do not attempt to set the idle speed until you have fixed all the codes and are sure that there are no vacuum leaks.

Warm the engine up to operating temperature, place the transmission in neutral, and set the parking brake. Turn off lights, A/C, all unnecessary electrical loads. Disconnect the IAC electrical connector. Remove the SPOUT plug. This will lock the ignition timing so that the computer won't change the spark advance, which changes the idle speed. Note the engine RPM: use the mechanical adjustment screw under the throttle body to raise or lower the RPM until you get the 600 RPM mark +/- 25 RPM. A wild cam may make it necessary to increase the 600 RPM figure to 700 RPM or possibly a little more to get a stable idle speed.
Changing the mechanical adjustment changes the TPS, so you will need to set it.

When you are satisfied with the results, turn off the engine, and re-install the SPOUT and reconnect the IAC. The engine should idle with the range of 650-750 RPM without the A/C on or extra electrical loads. A wild cam may make this figure somewhat higher.

An engine that whose idle speed cannot be set at 600 RPM with the IAC disconnected has mechanical problems. Vacuum leaks are the #1 suspect in this case. A vacuum gauge will help pinpoint both vacuum leaks and improperly adjusted valves. A sticking valve or one adjusted too tight will cause low vacuum and a 5"-8" sweep every time the bad cylinder comes up on compression stroke. An extreme cam can make the 600 RPM set point difficult to set. Contact your cam supplier or manufacturer to get information on idle speed and quality""""
-------paste-----

In addition to this, I found Brew2L's base idle reset video. He actually made another video a full year later and mentioned that he left out something in the base idle vid. You would have never known to look there though unless you were just keeping up with him. He also added a note in the description of another item he skipped past. So there's that. Having said that, his video is by far the most detailed and walks you thru almost every single step.
You could use @jrichker post and the Brew2L video and get it done. Or you could guess at a couple things. My point in all this was to say that at no time did I find any one post, video or otherwise that had everything.
I intended to sit and write it all out while sitting in the car. As I mentioned above, unexpected family stuff got in the way.

So let's go......

Before you start:
-Make sure your distributor will allow full movement to adjust timing. Things could move once you actually set everything correctly. My TFI hit the thermostat protrusion of the lower intake and would only go to 6 or 7 degrees. If I stabbed it the other way it was useless. So guess what. This meant I had compensated for the low timing and low idle with the throttle blade stop. This also meant that once I set timing properly, everything else was off a decent amount. I had to clearance the corner of the TFI module in order to get total adjustability. You can't know these things unless you go ahead and set the timing.
-Car out of gear, e brake on, timing light set up, multimeter ready for the TPS adjustment, all necessary tools ready.

Now do the process.
1. Warm the engine up to normal operating temperature.
2. Turn all accessories off. Lights, radio, hvac, etc.
3. Unplug the IAC electrical connector.
4. Remove the spout plug at the distributor connection.
5. Start the engine.
6. Idle the car to 600-650rpm using the throttle blade stop.
7. Turn the engine off but leave the key in the on position.
8. At this point you can set the TPS. (I'm not getting into the TPS setting debate. Put it on .9 anything and it's fine.)
9. Turn off the ignition and reconnect the IAC electrical connector and plug the spout plug back in.
10. Disconnect the negative battery terminal!!!! Let the car sit for at least 30 minutes.
11. Reconnect the battery.
12. You should still have all electrical accessories off. Start the car and let it run for 2 minutes. You should see the computer make adjustments. Time this with your phone or watch. Don't guess at it.
13. Turn the car off for 2 minutes.
14. Now turn the HVAC blower motor to high. Turn the A/C to Max. Turn the headlights on. Turn the radio on. 70's or 80's stations give the best results!
15. Start the car and let it run for two minutes. Don't guess at the time.
16. Turn the car off.
You should now have the base idle reset done and your car hopefully won't stall every time you stop. It should have better manners across the board.

This should clear up -- when to plug the spout connector back in, when to disconnect the battery, and how long to wait for the computer to make adjustments, and the process of starting the car once with all accessories off then again with all on.

Hope this complete list can make it in a spot just for base idle reset only. It's sole purpose is to help folks.

I pecked all this out on my phone so I'll proof it all next time I'm online with my laptop.
So you are telling us that the missing step is to check the ignition timing?

The fact that you can't get the ignition timing to the 10° mark because the TFI module hit the thermostat housing is a clue to other problems.
1.) The distributor is installed 1 tooth off. The helical cut gear causes the rotor to move when the distributor is installed. Most people just rotate the distributor housing unto the rotor lines up with the notch or mark on the distributor housing. The car runs Ok, but you have problems getting the timing set to factory specs or advanced to 12°-14°.
OR
2.) The timing rod inside the distributor has been damaged or is incorrectly installed.
Yes, there is a timing rod inside the distributor, it moves the plate that the ignition trigger sensor mounts on. The older carb cars used the same trick to make the ignition vacuum advance work. On EFI cars, it makes it easier for the assembly line people to get the timing set correctly with minimum effort. They probably have a jig or guide plate so that they get the distributor in the exact same place on every engine. If they need to adjust the timing, they remove the cover plate on the side of the distributor and swap the timing rod for one with the different timing specification.
 
  • Useful
Reactions: 1 user

Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
1,260
690
143
Nope. Your procedure is buried in the massively long (and really good) checklist. Not everyone needs to go thru all that just to do the reset. So I pasted the part folks would skip to because they aren't doing all the other. In that spot I wrote down the steps. Wrote down the steps from the best YouTube vid. And the steps from the same guys vid that was humble enough to say he left out a step. Good on him. Put all that together and made one actual spot with everything. Just trying to help. I'll never be able to help folks as much as you have. I'll just try my best when I can.
Tfi deal....Clearanced the corner of the tfi and it swings freely. Wasn't a tooth off or any of that stuff. I've noticed that some tfi modules are fatter than others. I have several of them and some don't hit...some do. Simple issue.
Thanks for the post. I enjoy chatting with you...Just don't get the chance often! :)
 
  • Agree
  • Like
Reactions: 1 users

CAMTWO1070

Active Member
Dec 17, 2021
145
43
38
For some reason why this title caught my eye so i was curious as to the procedures ithers state and with the procedure outlined I see some issues..

One is about disconnecting the spout connector,,,You are setting base idle not checking timing or resetting advance/retard...


Instead of writing the procedure I follow which is slightly different Ill just post a picture of it...

BASE IDLE LEARN PROCEDURE.jpg


Another thing I want to touch upon is the IAC and modifying the intake air system whether adding a cold air intake and removing the hotwater line that heats up the throttlebody . By removing theheat you get cooler air which is denser so you dont need as much air to correct idle especially after youve just set the base idle...

If you still get idle fluxuations after doing the procedure you may have issues like a worn out throttlebody with massive leaks at the shaft ends ,vacuum leaks or you may need to do a timing check and reset the timing advance by disconnecting and reconnecting the spout connector.

Another thing that comes to mind is needing to replace your timingchain or servicing your fuel injectors.

But after doing everything known to the forum the next course of action is to reduce the air that the IAC flows and thats done by doing this simple thing,,,,

IMG_20220304_134741.jpg



Good Luck with your rides.......
 
  • Like
Reactions: 1 user