Can the ECM compensate for engine wear?

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Chris142

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As my Jeep ages it's power and economy is going up. I have not done anything to improve the power or mpg.

I'm wondering if the ECM may be programed to step up the power as the miles add up to compensate for engine wear? The power increase was very noticible @ 92K.

I wonder if the ECM does increase the output but if the engine is still very healthy if that could be the reason for my sudden power increase?

Tonight for giggles I checked my 0-60 time. It did it in 10 seconds. Not as fast as most cars but plenty for a Wrangler with oversize tires and a fat guy driving.

When it was new I was lucky to get 18.5 mpg on the highway. Now I often get 22mpg and even saw 26 mpg on one trip which is outstanding for a Jeep.
 
No, the ecm does not compensate and cant compensate for wear. All it does is look at some data inject some fuel and set up the timing kinda.

Why the jump im not sure, it makes no real sense. unless its turning into a snowmobile setup, which is... the motor runs its best just before it blows up.
 
Originally Posted By: Petrou


the motor runs its best just before it blows up.

Thats a Cummins thing too
crackmeup2.gif
 
Years ago (OBD I times)GM PCMs had semi metallic shorting bars between contacts on the mainboard. The bars were designed to erode away and go open after a predetermined time as current passed through them. It supposedly took the engines out of break in mode and bumped timing and fuel curves to default.
 
I know with the electronically controlled diesel engines, especially the HEUI engines, the computer can sense slight variations in engine rpm in relation to what cylinder is on compression, exhaust, etc. It then compensates by adding more fuel to the other cylinders, injectors, whatever you want to call it. I doubt you'd really get more power from this however. If an engine isn't running just right, this will usually tell you which injector is not firing/working as well as it should as that's most often the cause.
 
it does indirectly. Load and combustion efficiency are going to be based upon engine cleanliness and wear state. As the engine breaks in, the ECU is alwas going to strive for timing advanced as possible without knock and to balance the A/F ratio. As the engine gets "better", the ECU will adapt slightly to the changing operation. Plus, it may lean out based upon driving style, perceived octane and resistance to knock, etc.
 
Originally Posted By: Onmo'Eegusee
Thats just the 4.0 finally breaking in.

+1. Once an engine is fully broken-in an engine has the least friction loss and the most power. Many long term car tests would show the car got quicker after say 30K miles from when tested new. The OP has a little more miles though but maybe the engine just has completely hit it's "sweet" spot.
 
Do you have really sick friends who sneak over to your house at night and add 2 gallons of gas to your gas tank. I did that to a friend once as a joke for 2 weeks then went back and siphoned out 2 gallons. He went crazy bragging about his high MPG only to go crazy when it dropped by almost 50% the following month...
crackmeup2.gif
 
The Chrysler transmission computer definitely accounts for wear. You can scan it for "clutch pack values" (my, wrong, term) to see how worn it is.
 
Originally Posted By: JHZR2
it does indirectly. Load and combustion efficiency are going to be based upon engine cleanliness and wear state. As the engine breaks in, the ECU is alwas going to strive for timing advanced as possible without knock and to balance the A/F ratio. As the engine gets "better", the ECU will adapt slightly to the changing operation. Plus, it may lean out based upon driving style, perceived octane and resistance to knock, etc.


Works for many ..but no for us jeep owners. We have no spark retard/knock sensor.

He may have reached the limits on his fuel trims and can't add anymore pulse width. A few more long high speed runs will burn a hole in one of the pistons
lol.gif


Aside from beating the tar out of the 4 bangers with big meats and flogging them, a hole in the piston is not all that uncommon if operated at high speed. The system is too numb to do anything but read average A:F ratio ..one lean injector and sooner or later it just burns a hole in the piston.


Chris: Run some Regane and see if you suddenly get all kinds of power for a few days.
 
Originally Posted By: PT1
Do you have really sick friends who sneak over to your house at night and add 2 gallons of gas to your gas tank. I did that to a friend once as a joke for 2 weeks then went back and siphoned out 2 gallons. He went crazy bragging about his high MPG only to go crazy when it dropped by almost 50% the following month...
crackmeup2.gif



LOL thats hilarious- can't really do it anymore, since most cars have anti siphon valves nowadays.
 
I was going to suggest the colder weather can make a car peppier, cold dry air allows a little more O2 into your engine. Maybe it was cold day in your neighborhood?
 
What do you mean by improving mileage?

"My mileage sucked but is coming back towards EPA."

.or.

"I'm now beating EPA mileage handily."

Changing gas stations could cause one. The other would be magical.
 
Originally Posted By: severach
What do you mean by improving mileage?

"My mileage sucked but is coming back towards EPA."

.or.

"I'm now beating EPA mileage handily."

Changing gas stations could cause one. The other would be magical.
EPA milage was 19 on the hwy. I often get 22 on the hwy and even saw 26 once but that was with a 60 mph tailwind. Milages checked by gps and not the speedo.
 
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