Hi,
Lately my engine has been cutting off when I am driving and the tach and speedometer read 0. A second later, the dash lights come back on and if I am going fast enough the car starts on it own. If I am going slowly I have to turn the key to the start position and the car always starts. Since the car either starts on its own or by me turning the key I assume that this is not a fuel problem. To me, that means it is an electrical problem. What should I start looking at?

Thanks,
Jomo

 

I sounds like you are losing a lot there, dash, engine and who knows what else.
Since there are many areas failing at once my first thoughts are with the ECU connections. These are known to suffer from corrosion over time.
If you find corrosion then it should be just a case of cleaning the connectors
After that I would go through engine bay connections and check for corrosion on the wiring blocks and connections.
Hope that helps

 

Definitely sounds electrical. It would be worth checking your main earth connections. A known problem area.

 

As above, also a failing ECM Controlled Relay (front right of engine bay) can produce those exact symptoms.

 

I swapped out the ecu and its relay with another set I had and that seemed to fix the problem. I drove today about 100 miles and the car did not cut off once.

 

That's good to hear.
Did you notice any corrosion on the connectors to the ECU?

 

If you can be bothered to do it, it would be worth putting the old relay back in to see if the problem returns. That way you would know whether the old ECU was ok, and worth keeping as a spare. My bet is that it was the relay as Brendan suggested.

 

I do plan on putting back the old relay to see if the relay or the eco was the problem.

 

No corrosion at all on the ecu connectors.

 

Today, after driving over 150 miles without any trouble, the problem came back where my car cuts off.
I suspect that the either the contacts on the relay and/or on the ECU are not completely reliable.
What is the best way to clean all the contacts on both plugs for the relay and the ECU plugs?

 

G’day Jomo,

My car stopped dead one day and it was faulty relays in the rear seat heel boards. I replaced both relays and have had no problems since.

They are both IGN relays and control a whole host of things.

It may be worth checking for intermittent operation of these relays.

Cheers,
Jeff.

 

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