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

[Unlogic]

I'm still on original ECU capacitors but I checked them today and they were all fine. I think the cold climate here lessens the wear on them.

[Ray]

Subcribing

[BlackStealth]

About two years ago, a local 3Ser was having trouble with their car and suspected his ECU. He brought his ECU to me to have the caps replaced as they were still original caps. The caps had no signs of leakage, and no leakage on the PCB either, so I was shocked to hear this fixed his trouble -- I always had thought bad caps could be visible inspected, I was wrong. Yes you're correct, cooler temperatures do extend capacitor life, but I'm sure Sweden and Canadian temperatures aren't that much different.

Next I had read somewhere that a user who never had any problems with communicating with the LCDBC via MUT, suddenly had new problems when he swapped out his ECU for a flashable version. Hmm, I wonder if the flashable ECU he swapped in had capacitors in poor shape? In case you're wondering yes flashable ECUs work fine with the LCDBC cause that is what I using.

Anyhow, any chance you could temporarily borrow another ECU and see if that makes any change?

Next, I've spent time analyzing the USB VAG OBD2 cables and discovered one major difference. The USB VAG OBD2 cables interpret anything above 2.5 volts to a high signal, whereas the official OBD2 chip interprets 35% of battery voltage and above to be a high signal.

[99 vr4]

I have had problems with communication with a Flashable ECU while tuning and have had to disconnect the LCDBC because it was NOT compatible. I can't remember if it was an issue with EVOScan or ECUFlash that prompted this, but I think it was ECUFlash. This was with a NEW ECU with NEW Caps so that was definitely NOT the problem. As soon as tuning was done, the LCDBC was hooked back up and all was well. Just have not had time to PM you about this and it seems that Greg had confirmed this and given me the solution so I assumed you knew about this.

[fastbikes76]

Does it on BOTH my cars so that rules out the ECU caps as surely ALL our cars are not at fault.

There is only one thing in common between all the cars suffering with this issue... The LCDBC .

[BlackStealth]

I'm confused, when you completed your tuning session it suddenly worked with the LCDBC? I don't understand the solution.

Well, it's good to know ECU caps aren't a problem then.

I will copy the "USB VAG OBD2 cable" design since fastbikes76 says that works good.

[fastbikes76]

Hi,

Yes the VAGCOM cable I use when logging directly from OBD port to laptop works absolutely 100% faultless and spot on with no corrupt logs.

Adding around 20ms delay on the LCDBC helped but still have delays as freezing issues with corrupt logs.

Look forward to an end resolution as I have two units and can't use either properly as yet.

Regards
Elton

[BlackStealth]

Here is the USB VAG cable converted for use with the LCDBC as a serial version that fits in between the LCDBC and the serial OBD2/MUT cable. I posted this in case Unlogic wanted to get a head start. No surface mounted parts so it's easier to build.

I am going to optimize the PCB a bit further before I send the design away to have it fabricated.

[jba3]

WOW! Glad to see this thing is still going and getting updated. One of my favorite VR4 additions. Hoping to get some money I'm owed soon, and get my VR4 back on the road. It's been down way too long.

Small feedback: In the user manual (http://lcdbc.xp3.biz/Version2UserManual.pdf), it says:

98/99 3000GT=Yes. Adds support for different real fuel trim codes on 98/99 3000GT cars.
98/99 3000GT=No. Uses standard rear fuel trim codes (94-97 cars)

The first "98/99 3000GT" isn't bolded (but I think should be), and it says "real" fuel trim, instead of "rear" (second line is correct).

[NickS VR4]

Awesome. I haven't been following this thread too much. Which versions of the car will need this, and how much will this piece cost?