Reset ECU after fixing boost leaks?

[kenamond]

I am working slowly through all of my boost leaks (work+family=not much time). I've been running rich for about 1.5 weeks (120 miles, 3/4 tank of gas ), and I'm wondering if my ECU should be cleared after each leak fix since it can't detect rich condition (or can it?) to know that it now needs to lean things out.

So should I reset the ECU? If so, I just disconnect the neg battery terminal and wait a few minutes? Is 5 minutes good enough? 10? ??

How long (miles, minutes, whatever) does it take the ECU to dial itself in after I've reset it?

Is there a good reference describing what the ECU does? Semi-low level descriptions would be great!

Am I full of it?

Thanks!

 

[ilikespeeding]

I am working slowly through all of my boost leaks (work+family=not much time). I've been running rich for about 1.5 weeks (120 miles, 3/4 tank of gas ), and I'm wondering if my ECU should be cleared after each leak fix since it can't detect rich condition (or can it?) to know that it now needs to lean things out.

So should I reset the ECU? If so, I just disconnect the neg battery terminal and wait a few minutes? Is 5 minutes good enough? 10? ??

How long (miles, minutes, whatever) does it take the ECU to dial itself in after I've reset it?

Is there a good reference describing what the ECU does? Semi-low level descriptions would be great!

Am I full of it?

Thanks!

I know how to do it on a 3G, so Im assumming it cant be but so much different. So here it goes because no one else was answering. I disconnected my negative battery cable for 10 minutes and then idled the car for another 10. After that, I drove for 10 miles at 60 miles per hour on a local highway then shes all good. I think the last part can be left out, but no need to short change on good measure.

In the simplest terms, an ecu is a computer system to control and monitors the engine by actuators and sensors.

 

[kenamond]

I know how to do it on a 3G, so Im assumming it cant be but so much different. So here it goes because no one else was answering. I disconnected my negative battery cable for 10 minutes and then idled the car for another 10. After that, I drove for 10 miles at 60 miles per hour on a local highway then shes all good. I think the last part can be left out, but no need to short change on good measure.

Thanks. I don't think I had the neg terminal disconnected for 10 minutes while I plugged my PCV line (damned leaking brand new PCVs aggravate me). I'll try an hour just to be safe.

In the simplest terms, an ecu is a computer system to control and monitors the engine by actuators and sensors.

Thanks, but I was looking for nitty-gritty details. I write scientific computer code for a living, so I'm unusual enough to enjoy that sort of info. I helped a bit in college with tuning a racecar we built which used a TecII ECU, and I got to see fuel maps, timing advance maps, closed- versus open-loop O2 sensor setups, etc. during dyno tuning, so I'm wondering about those sorts of details. With respect to my rich issue, I'm wondering how the ECU adjusts away from rich condition if it does at all (if it doesn't I need to wipe its memory back to the base maps so that it can figure it all out again).

 

[Chief Brody]

If you had a boost leak your car would have been running a bit rich since you were losing some metered air. In closed loop, the o2 sensor feedback told the ECU that you were on the rich side and you fuel trims likely went negative to compensate by removing fuel. If you had a datalogger you can see the short and long term fuel trims.

When you reset the ECU, the stored fuel trims are erased and you shouldn't set up large negative fuel trims to combate the rich condition you had experience because of the boost leak. It would have done this anyway without reseting it, but would have taken a while to do so.

 

[ilikespeeding]

Thanks. I don't think I had the neg terminal disconnected for 10 minutes while I plugged my PCV line (damned leaking brand new PCVs aggravate me). I'll try an hour just to be safe.



Thanks, but I was looking for nitty-gritty details. I write scientific computer code for a living, so I'm unusual enough to enjoy that sort of info. I helped a bit in college with tuning a racecar we built which used a TecII ECU, and I got to see fuel maps, timing advance maps, closed- versus open-loop O2 sensor setups, etc. during dyno tuning, so I'm wondering about those sorts of details. With respect to my rich issue, I'm wondering how the ECU adjusts away from rich condition if it does at all (if it doesn't I need to wipe its memory back to the base maps so that it can figure it all out again).

Well, typically the ECU can tell if the car is running too rich or too lean by the front 02 sensor. The engine should be a little hesitant to take alot of fuel out because when the 02 fails, it reports a rich reading. But, the ECU will take some out.

 

[kenamond]

Well, after fixing my TB gasket leak and PCV leak I drove an 80 mile round trip with about a 2000ft elevation change each way (down then back up each way), and used 1/4 tank, so that's roughly 20mpg which is a HUGE improvement. I did the round trip to go to the nearest Mitsu dealership to order injector insulator and o-rings (insulators are next boost leak to fix). Picked up an OEM PCV valve, too, which doesn't leak, so I can unplug my PCV return line now and set it up properly again .

How long does it take the ECU to drift away from a rich condition? Minutes? Hours? Days?

Thanks! (Still wouldn't mind a "Gross Anatomy of the 2g Turbo ECU" link )

 

[nightspeed87]

mines feels like it takes like a good three four days of city driving to reset, i dont know about highway driving but mines is ###, yours may only take minutes maybe,.

 

[kimcheefists]

I know this is an old thread but I wanted an answer to a question that I had. I recently changed all of my vacuum hoses to silicone and in the process I had to remove the battery to get to the vacuum lines on the back of the intake manifold. Well after re-connecting the battery and driving to work, it felt as if there was some power loss. Is this normal after the ECU is reset?

 

[ramsack]

There's no long-term memory on how the car is fueled, it is constantly updating fuel trims. Readiness monitors take a while of driving and are just for reporting emissions. Stuff like the octane value change a lot slower, but once knock hits and keeps hitting the octane value lowers immediately, then it slowly changes again. That is how I understand things to work. Low-level in the computer world is the total opposite of what many would think

 

[kimcheefists]

So my "power loss" is due to another reason other than the ECU being reset? Granted, it's only my perception that it feels like my car has less power..

 

[ramsack]

Maybe you didn't connect the lines correctly or they are collapsing under vacuum?

 

[kimcheefists]

I'm pretty sure I connected all of the lines correctly since I replaced them one by one to keep track of what lines went where. Even if the vacuum lines collapsed, how would that explain the decrease in power when accelerating? I'd be in boost...

 

[ramsack]

Something has to have changed when you did the vacuum lines then. Unplugging the ECU will make it run funny for not even a minute when restarted.