Hi Guys!

It might have been mentioned already; This is for the B280F engine but is useful for every engine with Knock Sensors. Here is what I discovered about my engine:

1. Knock sensors:

I finally got rid of the Ignition error code (4 flashes). It was, as in 99% of the cases, a faulty connection. Torque the sensors to specs. I did some research and discovered that the sensor signal is only 50mV/g. Tapped the sensors with a wrench slightly and could see like 30mV on the meter. So the connection is the problem. I used some de-oxidation spray and bulb grease for all 4 connectors in the line between sensor and ECU. I slightly bent the contacts as well; the spring force looses tension after 15+ years.

There are 4 different connectors:

1. Connector on the sensor itself
2. Connector sensor cable and harness in the back of the engine
3. Connector between A-pillow and strut mount (4 pin, gold-plated)
4. Connector at the ignition ECU (black housing under dash)

The problem was finally found with connector 3. It uses these bad gray connectors, which are sealed with wax I believe. The wax gets bridle and the inner gold-plated connectors can simple detach! The outer gray plastic connector is still connected, so it is not visible on the first sight!

If you remove the connector from the ECU, the two most outer connectors are for the sensors. You can pull the cover of the connector and you will see the shielded cables next to each other. I do not know if they used the same color all the time and on all models, but mine where orange and green.

You should have let’s say 0.2 Ohms from the ECU to the knock sensor. (Make sure to “zero” the meter while short-circuit the return leads first). The absolute value is not important since the current is very low; it gives insights of the quality of the connection though.

I have almost a new car now!!

I still get sometimes a whole series of flashes in a very regular fashion, so it is not a repeating knock-signal (1 flash). It flashes like 15+ times. It is hard to concentrate on the light, the break between the series of flashes and on the traffic at the same time. I do not know the exact count, but it could be the 6 flashes code 3 times or a combination of different codes. Fitz, a very competent I was talking a lot about my car told me to get rid of my Platinum spark plugs and put some copper ones in the car which I did not completely understand back then. Here’s what I learned today on the board and this information makes sense with what he said: The cylinder #1 sensor (a coil) is triggered with the current through the spark plug wire of cylinder #1. Since the Platinum spark plugs seem to have a higher resistance (not sure about that, because this would mean the energy in the spark is less), it could cause the ECU to go into fail safe mode and retard timing.

The car’s response on the throttle is as you would expect it now!