plug in chip for ecu

Post by **Sveedy** » 27 Apr 2020, 08:51

So has anyone tried any of these plug-in chip upgrades for the ECU ? Seems like a simple way to upgrade ECU performance without having to replace it entirely. Just plugs into the ODB2 port. Is there a downside, other than occupying that port ?

befarrer · Post by **befarrer** » 27 Apr 2020, 18:34

I cant see them doing anything as far as running of the engine/performance. I don't even know how it would change any engine parameters knowing how the OBD II connector is wired to the ECM, via a datalink wire. If it could change anything, it usually interrupts the signal coming from the engine computer to the engine, doing anything over the dataline would be too slow. I guess what it could do is increase the rev limit, or speed limiter maybe.

Sommerfeldt · Post by **Sommerfeldt** » 28 Apr 2020, 03:37

Sveedy wrote: ↑27 Apr 2020, 08:51 So has anyone tried any of these plug-in chip upgrades for the ECU ? Seems like a simple way to upgrade ECU performance without having to replace it entirely. Just plugs into the ODB2 port. Is there a downside, other than occupying that port ?

Hey.

In a lot of newer cars, most engine real time data is accessible in through the OBD2 port, and can be modified there, or the ECU can be reprogrammed from it. Neither of those options will work for your 850, unfortunately. The OBD2 communication there is barely enough to get any real time data, and with the protocols in use, none of these "quick fix" things will do anything at all.

The good news is that it's not super complicated or expensive to get a spare ECU for your 850 turbo, then either find the ECU files you want (T5, T5R, R, etc), or modify on your own. I even made a rig to flash my ECUs on my own, which means my labrador could probably do it as well, if he set his mind to it.

If you decide to go that route, make sure you read all the info you can get your hands on - there are some nice wikis and tutorials floating around, and remember to stay safe and upgrade brakes and such if you tune your ECU.

- S

Post by **Sveedy** » 28 Apr 2020, 07:37

Yes I'd rather have a retuned ECU than a plug-in upgrade. My '96 seems to be rather difficult to both tune and keep the AC working.
I'm kind of in the process of having that done, but with the on going issues I'm experiencing with the outfit doing the retune, I might have to end up doing it myself. Do you know if the ECU I find has to be of the same year and turbo as well, or will a non-turbo ECU work just as well ? How much compatibility overlap is there ? I am far from computer literate but I am willing to try most anything once...

Post by **erikv11** » 28 Apr 2020, 08:07

Go with a tuned ECU, it is super easy to swap them. Any turbo ECU will work, get one from 96-98 HPT or LPT. Non-turbo ECU won't work. The AC is not an issue on your 96, it sounds like they don't know what they are doing (red flag).

Sommerfeldt · Post by **Sommerfeldt** » 28 Apr 2020, 08:45

erikv11 wrote: ↑28 Apr 2020, 08:07 Go with a tuned ECU, it is super easy to swap them. Any turbo ECU will work, get one from 96-98 HPT or LPT. Non-turbo ECU won't work. The AC is not an issue on your 96, it sounds like they don't know what they are doing (red flag).

Erikv11 knows what he's talking about.

As he said, if whoever is doing it thinks it's hard to tune and keep the AC on, that's a red flag indeed. Lots of people tune these themselves, and especially the M4.4 is wide open. I managed to tune and flash the M4.3 that was in my car, and had no issues with it. The M4.4 is far easier. Well, more accessible, in any case.

If you get a spare turbo ECU, there's also a few options for you, such as several "tunes" on the same ECU, for example. Or, have a regular Turbo ECU and an R ECU, and swap them whenever you feel like it. You can of course also blow up your engine fiddling with these things, but if you're careful, read things and ask before you do something you're not sure about, then you won't.

- S

Post by **Sveedy** » 28 Apr 2020, 08:55

I'm pretty sure mine is a 4.3. I have read about issues arising when 4.3 is switched to 4.4, so I'm guessing that's where the problem is.
Like I said it's all out of my wheelhouse so I'm feeling like I'm just going along for the ride right now. But I like knowing that I have options to fall back on if this all falls apart on me.

Thanks for the much needed positive input.

Sommerfeldt · Post by **Sommerfeldt** » 28 Apr 2020, 10:46

The M4.3 isn't really any more difficult to tune. You need to start with a factory bin file, and then you can modify that incrementally. Switching to M4.4 gave me quite a few issues as well, so I can see how that might be daunting. I have some bin files for the M4.3, so send me a PM if you'd like to take a look at them. Note that they're Euro spec, so my specific files might give you some hassle, but I might have a lead on some US spec bin files as well, if you decide to do it yourself.

All in all, I recommend staying with M4.3 - that gave me the best results, at least.

- S

Post by **erikv11** » 28 Apr 2020, 11:16

Yes, your 96 came from the factory with 4.3 Upgrading to 4.4 is very easy, but you do have to modify the 4.4 tune to accommodate the 4.3 AC setup. This is totally straightforward however, it was figured out years ago e.g. http://volvospeed.com/vs_forum/topic/17 ... n-a-flash/. What is still tricky and unsolved today is the AC setup on some North American model year 97 cars, as discussed on several posts here recently on MVS about that topic. Should be no issue for your car if the tuner knows just the basics of 4.4.

I run 4.4 on my 95 850 which also shipped from the factory with 4.3. It's great and trouble-free for me.

Sommerfeldt has done more ECU tuning than I have. I prefer 4.4 because I know how to do it but going with 4.3 is fine too.

Post by **Sveedy** » 28 Apr 2020, 12:50

Well thanks for all the input. It's really appreciated. Better response from here than the tuner. I don't know enough about computers to understand all, or any, of what's involved with this sort of black magic, so I'm really just looking at options if this situation doesn't end up working out. But I think it will. Just with all the frustration, those little plug-in upgrades caught my eye.