Engine computer reprogramming?

RitualHabitual

RitualHabitual

Jeep "wrangler"
Supporting Member
Joined
Apr 9, 2019
Messages
75
Location
Oregon (Willamette Valley)
I was watching a piece yesterday about how changing your air filtration system or exhaust from the factory options can result in reduced performance based on air flow that does not meet specifications that are programmed into the engine control module. The video wasn't specific to TJs but it got me wondering if I should look into reprogramming the ECM since my 4.0 manual was upgraded to a K&N filter and I recently swapped the muffler for Hushpower. Anyone have any advice in that regard? Thanks in advance!
 
Save the reprogramming for the major things that are hard set into the computer. The things you're changing should be covered by the adaptive memory in the ECM. There is a method to erase the adaptive memory and it will relearn your current configuration as far as it is allowed.

Memory erase ECM.jpg
 
See this thread for tuning options for your PCM:
97-06 Jeep Wrangler TJ ECU / PCM Tuning Options

Even without the K&N filter (which by the way is a poor quality filter, stock is actually better) and the muffler, with a good tune, you should actually be able to gain some horsepower (assuming the tuner knows what they are doing). It won't be anything earth shattering, but it would be something!
 
Wow, really cool stuff--more than I expected and lots to think about. I'll definitely reset the adaptive memory (no brainer there). Thanks @HarleyMick--that one is going into the TJ file. So nice to know about re-tuning options too. I'll have to spend some time learning the details. @Chris, did you end up employing any of those tuning options? Curious what people found worthwhile and what didn't make much difference. Really nice to know you can use it to delete catalytic converters, etc. If they go bad I'd much rather spend money on a re-tune and throw out the old cats. Simpler, lighter, and better performance--triple bonus!

I wondered about the K&N filter. A previous owner added it and was apparently pretty excited about the "upgrade" because there were K&N stickers all over the vehicle that I had to remove. Anyone know of a replacement cold air filter that works better? This is all I found and details are scarce: https://www.sbfilters.com/replacement-filters/filters-kn-intakes

Or maybe I'll find an OEM box and go back to old-school..
 
RitualHabitual said:
Wow, really cool stuff--more than I expected and lots to think about. I'll definitely reset the adaptive memory (no brainer there). Thanks @HarleyMick--that one is going into the TJ file. So nice to know about re-tuning options too. I'll have to spend some time learning the details. @Chris, did you end up employing any of those tuning options? Curious what people found worthwhile and what didn't make much difference. Really nice to know you can use it to delete catalytic converters, etc. If they go bad I'd much rather spend money on a re-tune and throw out the old cats. Simpler, lighter, and better performance--triple bonus!

I wondered about the K&N filter. A previous owner added it and was apparently pretty excited about the "upgrade" because there were K&N stickers all over the vehicle that I had to remove. Anyone know of a replacement cold air filter that works better? This is all I found and details are scarce: https://www.sbfilters.com/replacement-filters/filters-kn-intakes

Or maybe I'll find an OEM box and go back to old-school..
Click to expand...

I went with the HPTuner solution. Josh Pearl is the guy to go to for tuning with that software.
 
I had my ECM retuned also. My cat is on there for looks only (gutted) and there is no rev limiter. The red line on the tachometer is there for a reason though.
 
Lol yeah, this is really about extending engine life and maintaining power potential for me. I still have power and reliability, but mine is a higher mileage engine and even though I know these 4.0 I6s are built to last I'd love to extend that for as long as possible. My real concern was potential for increased wear due to alterations from stock. Really nice to know about the adaptability of the ECM. I reset the adaptive memory earlier today--peace of mind accomplished! It'll be interesting to see if/how performance is affected. I'll report back later if I notice anything significant.
 
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Oh, I typed this out to make the document easier to file digitally. Here's the text for resetting the adaptive ECM memory if anyone is interested in copy/pasting it into their own file:

From HarleyMick's document above..


Resetting the PCM on a TJ Wrangler:

This very simple procedure will erase the “Adaptive Memory” stored inside the PCM and allow a new “Adaptive Memory” to be developed.

After performing this procedure the PCM will re-learn and store into Adaptive Memory your engine’s performance characteristics.

Please perform these steps exactly as they are written, in the order they are written. This will cause the adaptive memory in the PCM to be erased and cause the PCM to go into Fast Learn Mode adaptive mode.
  1. Disconnect the battery terminals and touch them together for 30 seconds (This is to discharge the PCM capacitors, which maintain the Adaptive Memory).
  2. Reconnect the Battery Cables
  3. Turn Ignition Switch to the “On” position but DO NOT start the engine
  4. Turn Headlights “On”
  5. Turn Headlights “Off”
  6. Turn Ignition Key “Off”
The PCM Adaptive memory has now been flashed, or erased from the PCM.

When you start the engine it will be running off a set of pre-programmed tables that come with the PCM from the factory.

When you get the engine up to operating temperature the PCM will start to collect data for the “Adaptive Memory.”

The PCM will collect data for Adaptive Memory for the first 50 Warm-up Cycles. You will run a little rich until the PCM adjusts for the new air/fuel mix.
 
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pagrey said:
Your Jeep will be a tiny bit faster but what's the point? You're still going to be slower than a Ford Fiesta.
Click to expand...

I see your viewpoint, but you're not taking into consideration the things I did first as well as similar things others have done. Before I had it reprogrammed I changed the engine to a 4.7 L Stroker which is balanced and puts out around 300 HP with its 280 cubic inches. Even with the beefed up AX-15 5 speed transmission, the SYE and rebuilt Dana 44 rear axle with 4.88 gears I'm reluctant to bring it out of the hole on those 35" X 12.5" tires because it might break something. That's OK though, at a 5 mph punch it will pull the front wheels.

I think my little 20 yr old would give a Fiesta a run for its money and there are probably at least half a dozen guys and ladies on the forum with TJs that will outrun mine. Raw speed is not the primary purpose of a Jeep, but the power and torque that goes with it are helpful in the mud or on the rocks!
 
pagrey said:
They run 14s these days.

Nobody I know that does extreme trails needs more than 190hp but maybe you do more extreme stuff.

Do what makes you happy, I'm not trying to be negative it just reads that way.
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No worries, just playing with you. Ronda (my TJ) and I are both retired and mostly do car shows and easy drives on beautiful days. Every now and then at a red light.....;)

101257
 
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RitualHabitual said:
I was watching a piece yesterday about how changing your air filtration system or exhaust from the factory options can result in reduced performance based on air flow that does not meet specifications that are programmed into the engine control module. The video wasn't specific to TJs but it got me wondering if I should look into reprogramming the ECM since my 4.0 manual was upgraded to a K&N filter and I recently swapped the muffler for Hushpower. Anyone have any advice in that regard? Thanks in advance!
Click to expand...

Hp Tuners has their full suite available as well. A good local tuner can really do wonders on the engine performance.
 
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