Tuners Rejoice! Free Tuning For M4.4!


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help with a/c, tried the stock 98 ecu in my 97 and failed to notice that my ac was on, let it idle and switched my stock ecu back in, now the a/c compressor is cycling every few seconds with the ac off while at idle. Rpms stay at 1000 for 10sec, then dip to 600 after a click from the a/c compressor for 3 seconds and then another click makes the Rpms go back up to 1000 and the cycle continues. I turn the ac on and it stops. I have the dials to defrost and heat in the red. , please read the rest

I need help with the air conditioning now, it keeps cycling with the ac off!. I tried out the m4.4 ecu from a 98 c70 t5 auto ecu number 607 as soon as it showed up in the mail. I wasn't paying attention about the ac being on at the time.  I started the car and let it idle then shut it off and replaced that ecu with my original 97 850 t5 m4.3 ecu number 702 . I installed a manual boost controller right after replacing the ecu with my original and then noticed the idle not being steady. It will go up and down. It stays at 1000 for 5 seconds and then there is a click from the ac compressor and the repms drop to 600. That will last a second or two and then the Rpms go back up to 1000. The ac is in the off position with both one dial in the red for hot and the other on defrost. 

 I had thought it was a leaky hose from my manual boost controller installation until now. I just successfully flashed the 98 ecu with a 607 bin (and the ac mod)and took it for a drive. And while warming up it didn't happen , plus I forgot about it happening. So I took the new ecu for a run and wow! So nice! But!!! When i brought it back home the idle started that again. So I took the 98 ecu out and thought that was the issue. I installed my original ecu and decided to mess with the ac controls. The ac was off so I turned it on and the ac stopped cycling! 

 So did installing the stock 98 ecu(when my ac was on) screw up my ac? And what exactly did it do to it? Why is it cycling in the off position and then stops when the ac is in the on position? I flashed the 98 ecu with the ac mod too. 

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Venderbroeck suggested that I remove the software ac mod on the 98 607 ecu and reinstall it. He is thinking that my car might be thinking like a m4.4 instead of a m4.3 , my car is a 97 850 t5 auto with a 072 ecu.  I just got done flashing it and will be back shortly with the results! Thank you for chiming in Piet, I noticed that you were the person who wrote the a/c software mod on wiki. I was going to message you directly but I guess that is unnecessary now. 

Edited by mescalinedreamz
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Its fixed! Flashing the m4.4 with NO a/c mod fixed the issue of my a/c compressor cycling while ac was off. Venderbroeck gave me the idea to reflash it without the ac mod and I want to thank him for that, thank you Venderbroeck!

 Recap, installed stock m4.4 c70 turbo auto ecu 0 261 204 607 and let it idle and accidently had ac on. Installed original ecu 1997 850 t5 turbo automatic ecu 0 261 203 702 and turned the a/c off before I started the car. Then at idle the a/c would cycle on and off ever 5 seconds. The RpMs would go up then down when that happened. I forgot about it, then flashed the flashed m4.4 c70 turbo auto ecu 0 261 204 607 with ac mod. Took the car for a drive and at idle the a/c would cycle with the a/c OFF and dials at defrost and red for highest heat. I turned the ac on and it stopped. I installed my old unflashed stock m4.3 97 850 t5 ecu and the a/c compressor did the same thing. I reflashed the m4.4 c70 t5 ecu WITHOUT a/c mod, and the problem is fixed. 

 Sorry about the racap but it might help someone with the same issue. I know there were rumors of the a/c being killed by installed a stock 98 70 series ecu into a 850. Those rumors turned to everyone saying that it doesn't kill it , it just makes it inoperable until you install you're original ecu.  

 Thanks to everyone who helps on this board, everything you do helps so much! 

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Volvo has a habbit of mixing older and newer systems during transitions to newer models.

Apparently the 1997 850 models already have the newer AC of the 70 series installed but still uses the M43 ECU. 

Clearly they just adapted the M43 software to then newer AC.

 

Installing a M44 ECU or a 1997 model M43 ECU, modified for the newer AC  in a pre 1997 M43 car with the older type AC will  definitely NOT damage the aircon! The aircon just will not work.

 

The other way around, combining a pre 1997 M43 ECU with a car with the newe AC will eventually fry your AC compressor.

Edited by Piet
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Done testing the extended tables mod, works really fine.

This is how it looks like:compared to the original tables:

extendedmaps.jpg

 

extendedmaps2.jpg

Axis are also  rescalable.

 

 

 

 

 

At mescalinedreamz.

I'am not annoyed by your questions and certainly won't bash you for it, as most people here won't.

But wouldn't it be a good idea to open your own topic for it.

Cluttering this informative and somewhat technical topic with posts with so much text just asking for explanations ... well that is somewhat of an annoyance though.

Edited by Piet
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Back again guys with some more questions. I don't know if it's been discussed before but here it is.

I know there has been a modification to be able to set a target AFR using a wideband probe. Is it possible somehow to tune the maps so ECU will target at closed loop a leaner mixture ? Say I want a 15:1 AFR at light cruise, is that possible to set ? Because as far as I know even with Rev6, ECU still targets an AFR of 14.7:1 adding or substracting by STFT and LTFT regardless of what you set in the fuel map. I'm trying to increase my town mileage a bit :)

Thanks !

Alex

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With the software based wideband mod this is possible. I am one of the drivers using this after first trying a hardware based version.

The software mod Piet made has a lot of advantages: Exact control of your lambda value. Leaner on cruising, good for economy and for smoothness. And exact control of your lambda value under lod. Makes tuning a lot easier.

I prefer to talk about lambda, because it is less confusing if you drive on LPG as well. The changenfrom thinking in afrbto lambda took me a while but is was worth it. ;)

Edited by razorx
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Hi

My son Maarten (better known as venderbroeck around here) takes care of implementing our mods.

Best you PM him for the widebandmod or any other of our mods.

He only asks a relatively small donation for the effort it took for developing the mods and the effort it takes to implement the mods in your bin and help you with it.

 

With our widebandmod you can do exactly that what you described a few posts back.

Edited by Piet
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