ECU heat soak

[WYZEUP]

So as my car is up and running and can drive it...

im throwing ideas around trying to diagnose the problem.

it runs flawlessly at night when it’s slightly cooler but during the day when it’s warmer it develops a misfire and drops what I think is one whole bank. Will sometimes come and go other times will change with throttle input...

could the issue be the igniters in the ecu are getting too hot?

there is quite a bit of heat from the engine bay…definitely won’t need the heater in winter haha

[Jean]

Where do you have your DME located and how is it mounted? As you know the stock location is in the fuse/ecu box and there is a temp switch that activates a FAN inside the box to keep the operating temp down.

[WYZEUP]

The ECU is located in the factory e30 position. Being RHD it is up by the steering column on the RH side

Would ventilating the ecu (holes in the casing) or wrapping the ecu housing in reflective gold heat tape help?

[The Dark Side of Will]

Are you getting engine bay air through holes in the firewall?

[WYZEUP]

yes can feel warmth coming through from the engine bay

[Jean]

Add a fan

[WYZEUP]

I was considering wrapping ecu in gold reflective heat tape or possibly drill some vent holes in the casing???

[varg]

Reflective insulation is only going to help with radiated heat such as what you'd get from the infrared coming off of a glowing header and may insulate the ECU itself making any internal heat harder to dissipate, you need some air flow to carry heat away. Blow some cool air on it, use a decent sized PC fan and a duct feeding cool cabin air. There also shouldn't be any engine bay air getting into the cabin, you need to seal the firewall, and the firewall sheet metal is insulated from the factory, what happened to that insulation?

[WYZEUP]

Factory firewall insulation was removed to allow fitment of motor as there is very minimal clearance with the m60. and heat is getting in because it is so close to the firewall/ headers are very close. plus things like plug for heater hoses that are not connected etc.... so there is places for heat to get through

[varg]

You should get some stick on insulation sheets and insulate the inside of the firewall.

[e30davie]

Ill be the devils advocate and be highly suprised the ecu is overheating if its inside the car.

[dasmanschaft012]

Any CELs? Could be a coil overheating, idk. Could be a bunch of things.

[The Dark Side of Will]

Ill be the devils advocate and be highly suprised the ecu is overheating if its inside the car.

Me too. That's why I asked if he was getting engine bay air into the car.
He'd get pretty darn warm himself if it was getting that hot, though.

[dasmanschaft012]

Just for knowledge, I believe the ECU fan switch switches @ 111degF, or 44degC.
So if your ECU case is over that temp, the ecu might be overheating.
Id expect the ECU to be OK up to at least 150degF or so. Most modern automotive grade electrical components are good up to 125degC (257degF).

[delamaize]

Just for information. My DMU is just hanging out in my glovebox, Because I have not built a mount for it yet. Thus far, I have not had any issues with overheating. I did use a grommet around the harness where it comes though the firewall. I've been toying with the idea of building a mount with a fan or two built in, This is why it hasn't happened yet, I'm not happy with any of the ideas I've played with.