MoTeC Global Forum

Hi,

I have a strange problem.
I hardwired a fan for the FMIC into the Motec M800 on EVO9
1) 12V connection
2) Ground connection

So the fan starts when I put the ignition on.
If I start and run the car it works fine.

Then I disconnect the 12V cable (from the fan) at the ECU's side (cut it)
the car starts but runs on 3cyls, it stalls after +-5seconds and bangs and pops.

I then connect the 12V cable again (from the fan)
and it runs perfect again.



what is wrong here??


maybe different issue maybe related.
I also put an AEM 5 bar map sensor in the inlet manifold
and this occasionally reads totally wrong when tyring to startup the car.
also misfires.
But this is sometimes ok sometimes not.
If not related then I'll take it out of the manifold and put it inside the car
to protect it against heat/vibration.

So you're not running any sort of relay and have the fan wired direct to the M800?

Yes, that's correct.

Fan is a slimline fan and only needs 12V and ground.
So I wired the ground to the ground connection of the ECU
and 12v to a 12v plug on the ECU (on that 12V plug there are other sensors connected aswell)

No relay as this is a racecar and the fan can blow all the time, not an issue.

And what about amperage ? My fan will blow the Motec easly without relay...... is your so weak ?

Eric wrote:Yes, that's correct.

Fan is a slimline fan and only needs 12V and ground.
So I wired the ground to the ground connection of the ECU
and 12v to a 12v plug on the ECU (on that 12V plug there are other sensors connected aswell)

No relay as this is a racecar and the fan can blow all the time, not an issue.

Do you know the Current demand of the Fan and the Supply at the AUX on the M800 you're using?

No aspect of a cooling fan should ever be wired directly to the Motec, or indeed any ecu.

Either your explanation of wiring is unclear, or you have it wired very wrong.

If you want it to simply run all the time, wire it either to the main ignition switch and battery ground, or directly to the battery.
Obviously with suitable wiring and fuses.

Although I suspect, and hope that you havent actually wired the fan directly to any of the Motec's outputs. As there is a good chance of damage due to overloading circuits if you did.