DonE

http://www.link-electro.co.nz/home.html

ECU with lots of turbo options.

Dknebes

Don,

Your observation is interesting because I have had a similar problem. I have had inconsistencies when starting and running my car. My problem seems to be in the tps sensor which I replaced but still have an occasional problem. I was told by electromotive to set the tps voltage a couple of hundreds higher than the lowest reading. It seams to jump or increase voltage after starting which effects my idle and acceleration fuel enrichment. I was driving one day and my car was stumbling and hard to drive but while driving I turned off the engine and restarted and the problem went away. I have not had the problem since.

Geoffrey

The voltage change of the sensors is a common symptom of a ECU that does not use floating a ground circut. A ECU that uses a floating ground will always maintain the differential between 0 volts (ground) and the 5 volt supply to the sensor. This allows the sensors to return stable values back to the ECU. A car has a terrible electrical system with wide voltage swings and lots of noise. Floating grounds are one of the ways to mitigate some of these issues.

38D

Why not go with Motec or Autronic?

Dknebes

Geoffrey,

Is it possible to go to a floating ground with Electromotive? How would you wire this?

David

Geoffrey

I do not know if the TEC III has a floating ground circuitry or not since I don't work on them. The older models were not and I suspect that the III is not as well. Floating ground circuitry is something that would be designed into the board layout during the design phase and not something that is added later. Probably some EE out there could figure a way to add it after the fact, but it is not something that could be plugged in or added by a normal user.

DonE

I've had problems with sensors from the beginning - some my fault from wiring and others from hardware and software.

The first was the crank sensor and it had to be replaced. Then the car would die going down the road after 20 min. I traced this back to a bad connection in the AMP connector used to connect the ECU and harness. I had to tighen ALL of the connectors.

The next was the cam sensor not being recognized as Hall, but Clewett said classify it as Mag in the software - it just happens this way for some reason. Electromotive is clueless.

Next was the idle - I had to send the unit back to get the idle driver replaced. While they were in there, the replaced the board for me.

The next was erratic temp and TPS. This was cured by removing the 22 pin weatherpack connector I installed, and moving the spark plug wires at least 6 in away from the harness. Temp and TPS are now stable. Now there is no connector and everything is hard-wired.

The next was the MAP. It is all over the place - it varies by 10kpa up or down at idle but smooths out above cruise. I fixed this by adjusting the software to average the input. With the rebuild, I will reposition the dedicated port to ensure I am not getting pulses from the cams, but with an aftermarket Accufab TB, its diffcult. Now the idle is dead on and will not hunt. However, coming off cruise, you still have a 50/50 chance of the IAC working correctly to catch the drop in rpm and keep it from stalling.

WERK-I

Geoffrey has brought up some very good points, as usual.
You could remove floating grounds from the ECU, but generally this would involve putting the ECU and all its sensors on a separate power source. The ignitors may be run off the current DC power source in vehicle, but I am not sure. Depends on the ignitor trigger circuitry.
The more important thing that Geoffrey brought up is noise, both from the DC power source and the the sensors. All sensor wiring must be the shielded cable type and sensor cabling should NEVER be in close proximity of high tension(i.e.spark cables) leads. Sensors generally use TTL voltages which run very low values in the range of -5V, 0V, +5V. So any noise must be kept to an absolute minimum.