Eec Iv Fi Control System

[michics]

I have 95 GT with a broken 418w that will get rebuilt or replaced. I bought this car from previous owner knowing it had a bad engine. The engine has several broken piston ring lands and it had a dropped valve. So in showing pictures of the broken pistons to a engine builder, he said it looked like detonation caused the breakup. PO said that he had a conservative tune in it (although I don't think he tuned it ), also said it was low on fuel. The car was / is a high speed road course car. So once I get it running again I will need to find someone to tune this system for sure.

As I'm not familiar with these engine control systems , I've been wondering if there are some sort of detonation sensors that should be monitoring for this ? I have removed the engine and there are no knock sensors on the block.

So could someone please enlighten me how this system works ???

Thanks, Mike

 

[jozsefsz]

You're right, no knock sensors with our vintage. A road course car could go lean due to fuel delivery problems, so it's possible it wasn't the fault of the tune. Or it's possible that it was. Only one way to find out, and you already have that anwer.

There are a number of tables in the tune that dictate the spark advance at any time - based on temperature, load, altitude, etc. And modifiers (percentage and discrete) that further modify the spark. To some degree there's always uncertainty - based on quality of gas, fuel delivery issues, etc. A 'safe' tune retards the timing enough to keep the engine safe while leaving power on the table. That's just the way it is - with no knock sensors.

The EEC-IV tunes have some knock-sensor capabilities built in. I've read however that the board has no hardware components to actually support it, and know no one who has ever done so. You could run an aftermarket system like MSD if you wanted that extra-cost extra-feature. Leaves less power on the table while still being safe for the car, of course at a cost.