Open loop closed loop

04T-WRX · Jan 15, 2006, 11:26 AM

I know nothing about the Lancer ECU so take it easy on me.

This ECU does have an open loop mode correct?
If so at what RPM range/throttle position does the open loop mode turn on?
If the car is an automatic does that make a difference or does it make a difference depending on what gear the car is in?

On my subaru the car goes into open loop as low as 3000RPM's but only in higher gears because the throttle has to be at 100% for 2 seconds, in lower gears it comes on around 4500 I think, is a lancer like this?

The reason I am asking is because I have a piggyback ECU that could be hooked up to my G/Fs lancer while I upgrade to a more subaru specific ECU and am wondering how this one might work on her car. There is still a LOT more I need to look into but figured I would start with this.

-Travis

Johns Slow ES · Jan 15, 2006, 04:41 PM

what kind of piggy back is it? if it was made for a subarus i wouldnt just plug it into the lance cause it would have a different setup then ours and most likly mess something up unless it tuneable then u can search and find out info from Hobie and other more knowagleable people what u can set it at

as for the open close loop thing might want to ask boe or hobie they have messed w/ around w/ tuining a lot more than i have

WADADLIG_OZ · Jan 15, 2006, 07:03 PM

It's Hobie Kopek and Boe is a no show anymore.

PM Alchemist although he is scarce but he would also be a good source of knowledge.

WADAD

03RallyLancer · Jan 15, 2006, 10:11 PM

what pb do you have... i dont know exactly when it swiches over between loops as i havent gotten the digimoto yet... but im sure it is very close to your suby ecu in its switching between loops

**HobieKopek** · Jan 16, 2006, 12:39 PM

Yes, the Lancer (and all OBDII cars as far as I'm aware) run in both open and closed loop depending upon sensor responses. I'm not sure the conditions for open loop on the stock ECU (mostly because I don't have one), but I doubt it's much different than any other car. Did you need to know anything specifically? Some people have had problems with piggybacks on the Lancer (mainly that the PB's changes wouldn't "stick") but others have had great success.

Alchemist · Jan 18, 2006, 04:08 PM

Open loop, as far as I can tell (since I've never read anything definitive about it) happens at: 3000+rpm AND/OR 30%+ throttle (because cruising along maintaining speed takes very little throttle, something like 10%). So if you're cruising in 2nd at 5000RPM you're open and if you're doing 30 in 5th with your foot mashed to the floor you're also in open loop. this is the "fuel dump" mode but is also where your eManage type computers will be effective.

However, I have no info as to whether a traditional piggy will work on an AT or how it should be set up. I will recommend a "genuine" GReddy cable if you're using the eManage because the two clones I used (one I bought, one I borrowed) didn't work at all.

03RallyLancer · Jan 18, 2006, 04:12 PM

i have a clone one that works well... i checked 3 weeks after i tuned and everything was holding... wont check again till spring...

impetus19 · Jan 18, 2006, 07:04 PM

I concur with alchemist.. all of my wideband datalogs show my afr's dropping out of the 14.7 range (closed loop) after somewhere around 30-35% throttle range. It's pretty easy to tell because the ecu begins dumping fuel after that point.

blaze_125 · Mar 1, 2006, 06:57 AM

For people still wondering about open/closed loop... I hooked up the Auterra this morning to refresh my memory and figured I'd share the knowledge.

OpenLoop: Pedal to the metal.
ClosedLoop: Cruising, slight acceleration with very little throttle

**HobieKopek** · Mar 1, 2006, 04:43 PM

You probably won't be able to determing the open/closed loop transition point without seeing the ECU's parameters. There are SO many maps and trims that all overlap one another. I'm guessing RPM, load, AFR, TPS value, coolant temp, acceleration fuel trim (on top of TP), air intake temp, and sensor malfunction are all involved in determining whether the car runs in open or closed loop. These are just bare minimums that I can think of off the top of my head, but I'm sure there's even more. Some may override the rest in certain situations (stomping on the accellerator from idle or a sensor malfunction could both potentially put the car directly into open loop for example). There is a LOT of overlap that goes into the calculations determining this sort of status.