My LCD screen project, boost, WBO2, Knock, etc

[box]

I'm having a pausing/freezing issue with an OBD1 1991 ECU, also under load at high revs. Most of the time it is fine, I find if I start getting low knock counts (3-4), it will freeze as the revs rise, the display becomes completely unresponsive for about 3-4 seconds, the rotary knob does not work during this time.

I have run an earth directly from the battery negative to the ECU mounting bracket, the boost controller is earthed separately with its own lug (i.e. not spliced into the ECU ground) yet there is no change.

Am I seeing the same issue as the above posts? As far as I have read, it's only an issue on MUT/OBDII vehicles and it should be relatively bulletproof on an old girl like mine. Help!

[Unlogic]

Sounds just like the issues I was having before I switched to 99 ECU.

[BlackStealth]

Box: Someone else had the same weird experience in OBD1, and the problem is with your ECU itself. What appears to be freezing is the lack of valid OBD1 communication with the ECU. See if you can temporarily swap / borrow another ECU before you purchase another ECU.

[box]

Thanks for the replies! I seem to have fixed the issue (touch wood). I've been struggling with an intermittent stalling fault (and then no start until cycling the ignition) and a high RPM engine hesitation/miss which was stopping me from even reaching redline under boost. I was also suspecting an ECU fault, so I pulled it out again and checked it out, the capacitors had been replaced (albeit quite an ugly job was done with the cleanup and repair of the PCB tracks) so I was almost certain this was the issue.

Turns out my CAS was faulty, this was baked years ago from being too close to the single turbo manifold with no heat shields (I fitted heat shields after a couple of days, evidently the damage was already done). Replaced the pickup module with a 2nd hand unit and the engine is now running at 100%, funnily enough, the LCDBC also seems to be working as it should.

I haven't had a chance to scope the faulty CAS module yet, I guess it had a dirty signal output which got worse as the revs and load increased until it threw the ECU into a fit.

[timothyj94]

A couple of comments and questions I have...

1. It would be nice if the lcd wire had an inline plug/connector for easier removal of the dash cluster.

2. Where are you guys running your power wire? Looking for some ideas of what to tap into.

3. Best reccommended basic wideband o2? I am still stock I just want to read a wideband through this, I dont need anything fancy.

4. Someone should make a printable template for cutting the rpm guage.. that would be awesome. I might make one if mine comes out nice enough. That way you know exactly the best spot to cut.

[2fnloud]

A couple of comments and questions I have...

1. It would be nice if the lcd wire had an inline plug/connector for easier removal of the dash cluster.

2. Where are you guys running your power wire? Looking for some ideas of what to tap into.

3. Best reccommended basic wideband o2? I am still stock I just want to read a wideband through this, I dont need anything fancy.

4. Someone should make a printable template for cutting the rpm gauge.. that would be awesome. I might make one if mine comes out nice enough. That way you know exactly the best spot to cut.

Would like to add the inline plug/connector to the rotary knob as well, for those that install it in the bezel that surrounds the speedo cluster.

[BlackStealth]

How much interest is there if I made an external SD Card datalogger for the LCDBC?

I have purchased a bunch of these inexpensive 1.8" graphic screens that have SD Card connector attached on the back. I can produce a daughterboard that attaches to it, with it's own microprocessor + serial chip + 3.3v regulator. SD Card datalogging works fine as is. I may in the future add more capabilities to it, upgrading is simple as flashing new software to it. Price $60 USD. I think in the past there was about 2 people interested.

[2fnloud]

I have only been asking you to go public with this for a few years now. DEW EETTTTTT!

[green-lantern]

Bringing my question over here from this thread

http://www.3sgto.org/3000gt-stealth-...logging-3.html

I have a Black Stealth LCDBC and it's plugged into the OBD2 port in my ECU adaptor harness. Will it hurt anything or make inaccurate logs if I plug the Tactrix in the port on the dash and run the LCDBC on the port in the adaptor harness and use them at the same time?

Antero, I have a 95 NA car that I did a TT AWD conversion to and it still has the NA ECU wiring harness in it so it has the 1st gen ECU plugs in it. I bought your old adapter harness from you that has a OBD2 port wired in. Well since my car is a 95 it has a OBD2 plug on the dash also so I have 2 OBD2 plugs in my car. My question is can I plug the Tactrix cable in the other plug and data log via SD card while the LCDBC is still plugged in?

Edit: BTW I'm not sure it matters but I have a 98SL flashed ECU.

[BlackStealth]

Because you have a conversion harness made for a 1st twin turbo gen car, and not for a 95 NA, the OBD2 port on your dash is not fully functional -- specifically the ECU data portion. The other functions on the dash OBD2 connector for communication with ABS, ECS, etc are still there. So in some ways you can think of it as non-functional then.

Yeah, I think I had these graphic screens for 2 years now. I've been disappointed in the performance of many microprocessors when it comes to pushing data on the graphics screen, I finally found one that does a good job and it's also a perfect match because SD cards only work at 3.3 volts.