heo1977

Hi!


I bought a used Ralliart ECU for my EVO 6 TME. I took out the old one and set in the new one after i took two wires and set them in the opposite place if you understand.. f.ex. take a red and one blue wire and cut them and connect the red with the blue and opposite. This car has been driven with a ECU like this earlier so the wires are connected with cable shoes so that part was easy.



The problem is that when I accelrate (It seems that I need to get some turbo pressure before it happends) -the headlight (It is winther and dark...) dims a bit. It seems that the voltage goes down and stays there until I stop accelrate..
Not at a constant level, the light gets stronger, weaker all the time -when I'm accelrating quite hard. It is okay when accelrating "normal".


Have anyone any clue what this can be?



Experts, please answer.




Regards

Hans Erik

Myszkewicz

iTrader: (2)

So far, I'm thinking alternator or voltage regulator. I'll have to dig through the Raliart manual to find out how much control over the voltage regulator the ECU has.

Measure your battery voltage with the car shut off, and again with it idling. Post up the measured voltage.

heo1977

I shall try to measure it tomorrow! My measuring instrument has flat battery!

profkirby

Back when we all had V-belts it would mean the belt was loose. I expect the serpentine belts have enough friction area to not have this problem.

Myszkewicz

iTrader: (2)

Good thinking. Check belt tension, too.

heo1977

12.67 volts before i started it and 14,68 volts after.

Myszkewicz

iTrader: (2)

Okay, sounds like the alternator works at idle, then. Is there a place nearby that can stress test your charging system? Basically, they put a dummy load on your electrical system, and see if the alternator can keep up. Over here, many auto parts stores will do it for free, otherwise a repair shop can do it.

How tight is the belt, and what condition is it in?

DSMTurbo2

switch back to the other ecu and see what happens in the same conditions... I wouldnt be suprised if the ecu is limiting the charging capacity of the alternator during an acceleration event over a certain throttle position. the Alternator is a huge item of parasitic drag when it is charging the system (under load).

Might be a bit of a long shot, but kind of a neat idea if you ask me. We are thinking of doing something similar to this on out Formula SAE car via Motec.

heo1977

The car wasn't really at idle but at "fast idle".. It is cold here. It sounds like it tryes to take off when I start it. .


I shall check the belt and set in the other ECU this evening or tomorrow.
My poor EVO stands under 10 cm's with new snow now.... powder snow..

The best car under winther conditions I have ever tested. ; ))




Hans Erik

heo1977

I don't know. . .




I shall check the belt soon, The car has only driven 30 000 km/ 18 600 miles so i I guess that it looks brand new.

Hans Erik