'97 GLT ECU swap (M4.4 to M4.4), no AC afterwards.

[shaker_chi]

Here is a link to some good info about the A/C:

http://m44.wikia.com/wiki/M4.4_A/C_Converison

[Chuck W]

Here is a link to some good info about the A/C:

http://m44.wikia.com/wiki/M4.4_A/C_Converison

Way ahead of you there.

The main issue I have is that In reading up on this over the past couple months or so, I never came across the bit that a '97 GLT, which is an M4.4 set-up, would need the AC mod if an other M4.4 ECU from a '98 car was going to be used. I got that part now and am just trying to get together the stuff to flash an ECU. Mainly I just need to wire some things up and cross my fingers.
I've been collecting stuff, just didn't think I was going to need it for this project.

Also, previously I did the SAS-delete on this car (The air pump was dead), and did the diode mod inside the ECU. I did the same to the V70R ECU for this engine swap. I think I can delete it in the software now, so on this new ECU I'm using to flash, I'll handle it that way.

[erikv11]

Yes, it is much easier to delete SAS in the flash. Click, done. Rear O2 as well.

[Chuck W]

Rear O2 as well.

That'll be handy. There's no cat-con currently in the car (removed at some point before we got it), and the O2 sensors are just installed pretty close to each other. Removing that bit will be nice.

Hoping to work on my flash harness this evening.

Once I do the software AC mod to the bin, is it just a one-time thing? Or do I need to be sure to perform it each time after editing and before flashing?

[erikv11]

I usually check the bin each time just as a routine, usually right before flashing for an 850. The little software piece that Piet wrote is very nice. You start it up, point it to the bin and it will tell you if the file has been modified or not for AC. Click a button if not, then it is modified and ready to flash.

[Chuck W]

Good to know. Been busy this evening, so I'm just starting to prune extra connectors from my ECU plug.

Took the car out for a couple quick drives this evening. It's not messing around, compared to the LPT/13T tune. It's faster than my T5 right now, I would bet (Not that my car is "healthy" at the moment). It does rattle a bit under boost when you're really getting into it and it downshifts from 4th to 3rd, so we'll need to dial things back.

I'd really like to compare this V70R tune to the 607.

[Chuck W]

Tonight's project


Flashed a 607 bin with the AC mod and SAS Disable on it. Couldn't quite figure out where the disable was for the rear O2 sensor. Not too concerned about that at the moment, and I can always change it.

Too late to try it out this evening, but I'll take it to work and swap ECUs over lunch and see what happens.

Not sure if it's related to this whole thing, but the ECC has been completely flaking out the past couple of days. I get flashing lights, then they stop, but I get nothing out of it. No fan, no damper actuation.

The car runs great aside from that little detonation that I'll need to address, but I'm waiting to see if it happens on the 607 bin vs the 455 one. It's very punchy right now.

[Chuck W]

OK, well I had a couple extra minutes before I left the house this morning, and was able to swap in this flashed ECU. Car fired right up but the ECC still was acting up. I grabbed my spare ECC from my old '96 GLT and installed that before I left. That appeared to work, as the ECC controls came back with no flashing lights and it sounded like the AC clutch engaged.

Driving to work, the car drove fine, if a touch slower than the V70R tune. Still very strong. By the time I got clear of traffic and was really able to put my foot into it, the boost gauge swung most of the way to the right and the detonation reappeared. No biggie, I can fix that. The new twist was that the CEL would come on when the boost came up a bit, but then go out as I let off. Never happened on the other ECU.

I get to work and try and see if any codes were registered, but they can't seem to connect to the ECU. This is the "refurbished" ECU (Python) I pulled out of the '98 S70 T5M in the yard. Seems odd. Also, the AC doesn't appear to be working again...
One thing I noticed when I had opened the ECU case, just to check things out last night, I saw an extra wire soldered on the "B" side leads, buried down in the lower row. I hadn't noticed that on the other couple ECUs I've opened up (When I did the SAS delete diode mod). Was this something that was common from the factory, or is this some "cludge" that Python did when they "refurbished" it? Perhaps this is what's causing my communication issue. The unit flashed fine, once I got everything set-up properly.


Guess I'll have to wait until I get back home to stick the original GLT ECU in there, to make sure all the things work as they should. If so, then I guess I nuke out the tune on the V70R ECU for this new flash, and see if things behave.

[erikv11]

Flashing ECC lights is unrelated to the AC mod. The AC mod affects whether the compressor comes on when called for, or runs all the time and gets cooked, or doesn't run at all. The wiki page should outline this pretty clearly, see also the link I posted earlier. So the flashing lights is either bad damper motors (most likely) or a bad ECC unit.

If you are working with a modified ECU then all bets are off, don't think I would start out that way. The soldered wire does not sound factory, like you said. I've never had any OBD issues with a flashed ECU. Shame if you have to overwrite the R ECU. I might clip out the internal solder? Some risk there too ...

CEL under boost is probably knock sensors, rev5b reports that more sensitively than a standard tune, as a warning. You will have to do live monitoring to really figure it out, I have not messed with it on my cars. In that case there won't be any stored codes. Also note that you can store multiple boost maps and switch between them by depressing the throttle pedal with the key in position II. One is CEL off, CEL flashing, CEL on, etc. I know you're not loading multiple maps right now, just warning you that aside from what you've seen so far, you can get a harmless CEL for this other, unrelated reason, watch out for it. Cycle through the different CEL states next time you are sitting in the driver's seat in the parking lot, you'll see what I mean.

Volvospeed is a dirty word around here but keep in mind they are going to be an infinitely deeper knowledge source on tuning and flashing.

[Chuck W]

I didn't figure that it would be related, but seeing as the ECC was working perfectly before we did the engine swap, it was a little odd. I spent a lot of time sorting out all of the ECC issues with this car not long after we got it. It was kind of a mess, in that respect.
Swapping the other ECC module appears to have gotten rid of the error lights, but the AC is not engaging again.

Good info on the potential cause for the CEL under boost and the boost map switching. For this project, I really just need to try and decipher how to dial the boost back, or maybe pull a little timing.

One thing I didn't locate, that you mentioned previously, was to disable the rear O2. I didn't see that listed in the "Disable Diagnostics" section in TP.

I know there is A LOT of info on VS, including that HUGE thread on the subject. I've tried going through that, but at 450+ pages, it's kind of a mess.

So, at this point, I either flash over the V70R tune, or the original GLT tune. I've been using the GLT ECU as the "check" for the AC, so I may just have to sacrifice the R one. I've poked around on the Motronics Suite a bit, and may be able to pull some info on that tune for comparison later. I don't remember if it was fully supported or not.