Interestingly I decided today that I'd take my scanner into work along with the scope, which I normally keep in a travel bag with my NVH kit
Today I was asked to look at a VW Passat and change the EGR valve assembly which is down the rear of the engine. First time I've done one and started it this afternoon. I have got three bolts to remove and then the EGR valve assembly should be off. Tomorrow is another day.
Remember the Toyota!
We towed it in as a breakdown and the fault with the car is that the engine starts and then stops within a couple of seconds. Remember that the boss put his scanner on it and said there were no fault codes present and that live data was not showing anything obvious!
Well I thought while the boss has finished early today and I had taken my scanner into work that I would put the scope on the car and read some data from the OBD with my scanner.
Remember that the boss very specifically said that there were no codes recorded.
This is what the Toyota ECM(s) stored at time of inspection this evening.
Power train codes..................... = 12
Anti-lock brakes........................= 01
Airbag.....................................= 01
Air conditioning........................= 01
Electronic motor power steering = 01
Immobilizer.................................0
Instrument panel cluster...............0
Body (main) codes.......................0
Powertrain current codes;
P0103 Mass airflow circuit high
P0118 Engine coolant temperature circuit high input
P0351 Ignition coil 'A' primary/secondary circuit
P0352 Ignition coil 'B' primary/secondary circuit
P0353 Ignition coil 'C' primary/secondary circuit
P0354 Ignition coil 'D' primary/secondary circuit
Anti-lock brake codes
C1241 Too low or too high battery voltage
Airbag history codes
B1660 P seat airbag active mode indicator
Air conditioning codes
B1423 Open in pressure sensor circuit/abnormal refrigerant pressure
Electric motor power steering - current codes;
U0105 lost communication with ECM
Cleared all codes and carried out a re-scan;
Air conditioning HVAC B1423 as above is the only code that returned.
I decided then to put the scope on the ignition system as per Autodata wiring diagram for the voltage pins of each coil. Although the scope traces are saved on the computer at work I can advise that what I did was put channel A 20V on coil 4 battery voltage feed, I got 11.6V so I put the battery support unit on the car to assist and then got the 12V + back.
I decided to measure the current demand through each ignition coil, so I think I am looking at about 8A per coil. In practice I got;
Cyl 1 between 6 - 7A
Cyl 2 between 6 - 7A
Cyl 3 absolutely 0A no matter how many times I cranked the engine over.
Cyl 4 between 6 - 7A
When I read through the buffer I did notice that the above amperage readings did sometimes show significantly less.
Before I did this tonight I was fairly convinced that the fault was the fuel system, and today the boss wanted me to drain the 3/4 of a tank of fuel and put new in, however, doubt in my mind I thought what if I wrong and the fuel is OK!
So I got the electric fuel pump off the shelf and dropped it into a jar of new petrol and piped it up to the common rail, the boss cranking the engine and me powering up the fuel pump, then engine started and immediately stopped each time the key was tried, so no different with new fuel tried.
It looks then that something is pulling the ignition system down in operation, so I disconnected cylinder 3 coil and started the engine and exactly the same happens, so although the cylinder 3 is pulling no current, something else is pulling the current down and that does not seem to be the coil to me.
Tomorrow is another day...