Adaptive Learning? ECU Reset Learning Period

Terrorist 5.0 · Mar 9, 2024

It's been a while since the battery was last disconnected on my car, and today I unhooked it for about an hour to clear my IAT code (54), and after I reconnected it, I went for a drive and the car felt very different. I understand this is normal, but in hopes of learning more for the future, if there are any people experienced with these cars please answer me this.

A little background, I realize all these cars, whether 5.0 or 4.6, are known for hanging revs between shifts. Before I disconnected the battery, the revs would not hang that much, and would drop nicely when I pushed the clutch in. For reference in day to day traffic I normally shift at anywhere from 1500-2000. Now it holds the revs noticeably longer than before, especially when driving slow AND ESPECIALLY ON HILLS (it has always done it on hills but I am planning something to combat that at some point). On top of this, I found taking off to feel different too, nearly stalling a couple times and not being as smooth as I was before unhooking the battery. I should mention however that the car is running 8* of timing (planning to back down to 6 and go back to running on regular) on about a 50/50 blend of regular and midgrade to combat a pinging problem at WOT I am actively looking for.

Also, when I reconnected the battery, I let the car relearn it's idle. Started it cold, let it run for 2 minutes, shut it off, let it sit for 2 minutes, then ran it for 2 minutes with headlights, A/C and steering input for load.

Before it shifted nice, now I am considering one of those IAC restrictors lol

I just want to know how long the car is going to act the way it is being before it goes back to normal. I know all cars are different, and I just want to see if these cars have any secrets I am missing. Thanks.

ttocs · Mar 9, 2024

they are not known for hanging revs till certain parts are added to the car. I had it with my proproducts throttle body but it went away when I went to an Edelbrock. With the right parts and the tune to go with them it is not a known problem. If you do the adaptor do the adjustable one to be able to dial it in.

https://lmr.com/item/LRS-9939A/1986-93-Mustang-50L-58L-Idle-Air-Control-Iac-Adjuster

Terrorist 5.0 · Mar 9, 2024

ttocs said:
they are not known for hanging revs till certain parts are added to the car. I had it with my proproducts throttle body but it went away when I went to an Edelbrock. With the right parts and the tune to go with them it is not a known problem. If you do the adaptor do the adjustable one to be able to dial it in.

https://lmr.com/item/LRS-9939A/1986-93-Mustang-50L-58L-Idle-Air-Control-Iac-Adjuster

Its stock

duh09 · Mar 10, 2024

Base timing for these cars is 10*, if you're experiencing pinging at 8*, you've got some other issues you need to look into as well that I think are going to be the source of the issue more so than the ECU needing to relearn anything.

First things first, double and triple check that your balancer is in good shape. The rubber inner that connects the two halves together will fail over time and allow the outer ring to slip, making getting timing correct difficult as you're looking at the wrong number. If you see rubber squeezing out anywhere, or any pieces missing, it's likely due for a replacement.

The IAC valves can get sticky and gummed up. Try pulling it off and giving it a good spray-down with some brake clean before looking at replacements. IAC restrictors are an option, but they always seem to be a temporary one - the computer eventually seems to be able to compensate around it.

If the car is bone stock, the car should have 0 issue running like it always has with a battery pull unless something else is wrong.

Just thinking out loud more than anything at this point, but your PIP may be on it's way out. Ignition stuff can get a little wonky when they're dying, may be worth doing a little searching on the topic to see if the symptoms line up with what you're dealing with.

Terrorist 5.0 · Mar 11, 2024

duh09 said:
Base timing for these cars is 10*, if you're experiencing pinging at 8*, you've got some other issues you need to look into as well that I think are going to be the source of the issue more so than the ECU needing to relearn anything.

First things first, double and triple check that your balancer is in good shape. The rubber inner that connects the two halves together will fail over time and allow the outer ring to slip, making getting timing correct difficult as you're looking at the wrong number. If you see rubber squeezing out anywhere, or any pieces missing, it's likely due for a replacement.

The IAC valves can get sticky and gummed up. Try pulling it off and giving it a good spray-down with some brake clean before looking at replacements. IAC restrictors are an option, but they always seem to be a temporary one - the computer eventually seems to be able to compensate around it.

If the car is bone stock, the car should have 0 issue running like it always has with a battery pull unless something else is wrong.

Just thinking out loud more than anything at this point, but your PIP may be on it's way out. Ignition stuff can get a little wonky when they're dying, may be worth doing a little searching on the topic to see if the symptoms line up with what you're dealing with.

I didn't know the IAC restrictors can be compensated for, that is new to me, but very helpful since I have a cheap one now. I'm considering leaving it out for now because after 3 days worth of driving it seems like it has returned to normal. My balancer is in good shape, brand new in fact. Ford Racing, replaced it almost 3 months ago. I haven't had the IAC itself out of the car yet, I was thinking it was gummed up too, but its working good for me right now. About the pinging, I have checked a few things, and they seem ok. Still digging into it little bit.