Memory dump of ECU

[b3lha]

Thanks Calum,

I can't get the 393 to work no matter how I connect it. It won't drop the output to 0v. Maybe it's faulty?

So I got a 358 and connected it as per your original diagram. Seems to work on the bench, 3v for logic 1 and 0v for logic 0. I haven't had a chance to try it on the car yet. I really hope this solves the "92 problem".

Phil.

[b3lha]

Originally Posted by TomsSVX

should be getting my connector built soon... Will keep you updated on my findings

Tom

Thanks Tom.

If Calum's modified circuit works on my 92 then I'll be posting an updated howto in the next week or so.

[b3lha]

Originally Posted by strange179

I've got to say that this is a great discussion. I'll be really glad when we get it all sorted out for the '92s and can all have a reliable way of reading these ECU's. At this point the only possible assistance I might be able to offer is that I recently bought a SSM ver1 and I might be able to open it up and check out what it's using for interface circuitry. I'm not sure how helpful that will be but thought I'd offer.

Incidentally, if anyone knows the part number for the OBD1 SVX cartridge that goes in the SSM v1 I'd be happy to have that info.

Thanks, and good luck moving forward.

Jay

Hi Jay,

In the ECU section of the 92 service manual it gives the cartridge number as 498347500. However, in the TCU, AirCon, and Cruise sections the cartridge number is given as 498348500.

Hope that helps.

Phil.

[strange179]

Thanks, I didn't think to look in the FSM. Probably would have been a good idea to check there. Sometimes it's easy to overlook the simple things and go right for the more complicated ones.

Jay

[Nomake Wan]

I hate to be a bother, but have you tried that new circuit on the '92 yet? I'm anxious...

[b3lha]

Originally Posted by Nomake Wan

I hate to be a bother, but have you tried that new circuit on the '92 yet? I'm anxious...

Sorry for the wait. I really want to try it and I'm hoping to find time later today, but I have some other important tasks to do first. Watch this space.

[b3lha]

Originally Posted by Nomake Wan

I hate to be a bother, but have you tried that new circuit on the '92 yet? I'm anxious...

You can stop being anxious.

It works!!! It works a treat!!!

With Calum's modification to the circuit, the "92 problem" is SOLVED.

I'll make a little adapter board for your box just like mine and pop it in the mail to you.

For anyone else thinking about trying this, I'll be updating the howto in the next week or so, once I've written it up properly.

Phil.

[TomsSVX]

excellent

tom

[Calum]

Your welcome.

[Nomake Wan]

Yessssss!!!!!!!! Thank you Calum and Phil!!!!! So glad that this gremlin is exorcised.

[Calum]

Nomake, if you get a chance, I need a favor. Could you translate a document for me? This is the installation instruction for a Japanese ROM board and oddball ecu I'm working with, which also uses a M37791 processor like the SVX ecu. Sorry for the low quality, the Japanese company sent them to me like that (they don't speak English either). The top line on page 2 was cutoff on the original instructions too. I think I've got a pretty good idea on how this is supposed to be installed, but having the instructions in English would really help.

http://www.calumsult.com/calumsu/ran...structions.pdf

Thanks!

[svxistentialist]

Originally Posted by b3lha

You can stop being anxious.

It works!!! It works a treat!!!

With Calum's modification to the circuit, the "92 problem" is SOLVED.

I'll make a little adapter board for your box just like mine and pop it in the mail to you.

For anyone else thinking about trying this, I'll be updating the howto in the next week or so, once I've written it up properly.

Phil.

Good work Phil

Good work all. We really need to be able to read these paramaters if any serious work is to happen with the EG33

Nice one!

[b3lha]

I've put a howto on my website describing how to build an upgrade board using Calum's comparator circuit. Anyone who has built the original board and is getting corrupt data from their ECU should build the upgrade board and attach it to the original as per instructions.

I've been hoping to redesign the board from scratch and do a new howto. But I haven't had time to work on it. I can't promise when that will be done, so for now, build the old board and the upgrade.

[Nomake Wan]

Phil,

I plugged the (old) adapter into a 94 L yesterday and sure enough, it worked just fine no matter how much crap I turned on. Weird.

Just waiting on the mailman.

[b3lha]

I modified my software to frig the ECU's binary mode baud rate to 4808 before downloading from the ECU. The results were somewhat interesting. My original code took 24 seconds to query 256 addresses. The modified code took.........24 seconds.

Looking at the code it seems I was somewhat naive to expect that simply increasing the baud rate would increase the rate of logging from the ECU. The comms routine is polled using a timer.

To try and explain what is happening, let me try a bad analogy. Imaging the ECU is a guy putting boxes of data on a conveyor belt. Imagine the laptop is another guy taking them off at the other end. The laptop guy works on demand, every time a box arrives, he grabs it. The ECU guy works by the clock, he puts a box on the conveyor every minute. What I have done by increasing the baud rate is to make the conveyor belt wider (bandwidth!). The conveyor can shift twice as many boxes per minute and the laptop guy will grab them when they arrive, but it's futile because the ECU guy is still only putting one box per minute on the belt.

In order to increase the logging speed, we would need to reprogram the timer that governs how often the comms routine is executed. Maybe I'm wrong, but I don't think this is possible without burning a new EPROM.

So, in summary, I think we are stuck with 1953 baud binary mode or 4808 baud ASCII mode for data logging.