location of ECU test socket

[dadamsv8]

Help I have managed to borrow an ECU fault reader but can't find where I plug it in.

Any help/picture of location would be really appreciated

[miketvr]

The ECU and test socket are located in the passenger footwell next to the battery.

One thing that simple testers don't tell you is whether the speed sensor is working. I had a sophisticated Lucas tester which someone procured for me and that showed up that the speed sensor was indicating speed >3mph when the car was stationary. There is no fault code for this.

There is a converter behind the dash which takes the variable speed pulses from the prop shaft sensor and when the car is doing more than 3mph it emitts a square wave output which indicates to the ECU that the car is moving. The main use of this is to allow the engine idle speed to be set which can only occur when the car is at standstill.

The reason for the problem was a really poorly designed converter which is prone to electrical noise with the slightest of earthing deterioration. I modified the circuit to make it more tolerant.

I'm telling you all this because I think that this could be a problem on a lot of Chims/Griffs.

Best of Luck
Mike

[brianmillar]

Hi Mike

I would be interested to know what mods you did to the convertor unit.
Just in case I need it in the future.

Thanks
Brian

[spend]

Just in case there is any confusion, early cars do not have this arrangement... LT77 drives ecu, Speedo from propshaft trigger wheel.
Griff pre-cats have yet another arrangement...

Dave

[miketvr]

brianmillar said:

Hi Mike

I would be interested to know what mods you did to the convertor unit.
Just in case I need it in the future.

Thanks
Brian

Brian - I can't remember the fine detail off the top of my head but there is a comparator with the negative input grounded so any signal on the positive input greater than 0V will cause the comparator to flip/oscillate. Electrical noise in car electrics is more than enough to do this. I raised the voltage on the negative input by breaking the original connection to ground and using a diode biased via a 10-15K resistor to the +ve rail. This raises the voltage to about 0.7V.

If you don't have the necessary skills for the above then contact me if the problem occurs and I'll see if I can help you out.

Mike