Please PLease Pleas help
I have been messing about with the EC connectors that are soldered onto the board (I know i know, dont go there) Cut a long story short, I replaced the EC18 connector, I cut the pins, removed the connector and de soldered the remains of the pins of the board, a new connector was then soldered back on and re assembled the case. Now that I have put everything back together and put the Genboard back in the car, everything seemed to work untill i noticed shortly after starting the engine, that the Lambda reading was 13.4 fixed. Testing the Pump Zero DC gave Zero volts, testing Pump PID Nerst Target, volt reading between Ground and WBO2 pin 5 gave 4.11v, reading between WBO2 pin 1 and pin 5 gave 0.0v. PROBLEM. Adjusting the value changed nothing. All this was done as per Robs guide.
Removing the connector pin 13 from EC18 connector and measuring the volts to ground returned 4.11v, so the voltage is getting to the board.
I did some testing while looking at the schematic and board lay out http://www.vems.hu/wiki/index.php?page=GenBoard%2FVerThree%2FSchematic and found that the track on the board between EC18-13 and R144,R145,R146 must have been damaged as there was no continuity. Checked this furher by measuring the resistance between EC18-13 and 7, this should have read 1M ohm, again no continuity. Checked again this time at pin 10 on U17C,This should have read 10k ohm, again no contiuity. damaged track confirmed.
I repaired this by bridging from EC18-13 to the common pad of R144, R145, R146, with a very thin piece of wire. I checked everything again an the resistances returned were as expected.
Second attempt at checking the Pump PID Nerst Target but the volts between WBO2 pins 1 and 5 across the 100 ohm resistor still measured 0.0v, but this time the lambda reading remained ??.? however long I left it enabled (as per Robs guide).
More testing, and I have the following results. This is where my knowledge of electronics stops, I have got this far and Im now stuck. I suspect the LM324D Operational Amplifier is fried, but I have no way I can confirm this as I cannot for the life of me work out how these things work even after looking at the data sheet http://dkc3.digikey.com/Media/PDF/Data%20Sheets/Texas%20Instruments%20PDFs/LM124_A_224_A_324_A_K_KA_2903_2902V_K_KV_KAV.pdf
Results as follows.
Nothing connected to EC18-7 Pump-, or, EC18-9 Pump+
LM324D U17C
pin 8 reads 4.95v
Pin 9 reads 4.60v
pin 10 reads3.74v
Lambda reads 13.4 fixed
100 ohm resistor connected between EC18-13 nerst cell signal and EC18-7 Pump-, and another, again from EC18-13 and EC18-9 Pump+
LM324D U17C
pin 8 reads 0.465v
pin 9 reads 4.10v
pin 10 reads 4.09v
lambda reads ??.? fixed
volts across 100 ohm resitor between EC18-13 and EC18-7 reads 0.0v
Please can some one help and maybe diagnose the problem. I suspect the op amp, but would rather some one who knows what they are doing to look at this and maybe give some pointers as to what is going on
Looks like I will be putting the standard OEM stuff back on the car for the week end, we are off on a charity run, over 100 minis. Just hope the weather is good as it has been the last two years.
http://www.wirral-minis.com/WM/events/wirralllandudno.asp
http://www.wirral-minis.com/WM/Events/Review.asp?t=p&EventID=336
