ecu revs engine up to 4500rpm while stopped

[j2thed1993]

i have a link xtreme g4+ ecu running in piggyback mode ,and the e-throttle is connected to the link ecu , sometimes when sitting in traffic the ecu starts to rev the engine up to around 4500 rpm multiple times , and even after turning the car off then on , it starts doing the same thing again , the only way to stop this is by disconnecting then reconnecting the battery , what could cause this issue ?

my car is a 2011 genesis coupe 2.0t manual transmission.

[Adamw]

Can you attach the tune and a pc log showing this occurring.

[j2thed1993]

Hi Adam,

I don't have access to my tune file since it's password locked and regarding the logs , it's hard to record them since this issue rarely happens so i can't recreate this problem at will , i will ask my tuner for the tune file , but do you have any idea what could cause this problem to happen ? i loose control over the throttle when it happens and it revs high multiple times on it's own  , i also get multiple lights on the dash when it happens

[Adamw]

Obviously nobody can help you with no data and a password protected tune.  You will have to go back to the original tuner.  Most likely poor PID tune so it is faulting to safety mode.  Most throttles are spring loaded to about 10% so when shut off they spring open a little more than idle.  

[j2thed1993]

This problem apparently was caused by the overheating of the Link ECU , it is installed in the drivers cabin in the foot well to be exact , and i have some heat escaping to the drivers cabin through the foot well which causes the Link ECU to overheat , so i turn on the A/C on the coolest settings to cool down the Link ECU whenever it starts to get hot , and the problem never happens when i do this .

[Adamw]

I dont think so.  Our ECU's are tested to 70°C continuous and will take more than that short term.  The ECU will typically run about 5-10°C above ambient, so it is unlikely hot enough in the cabin of most cars to cause a problem. You can log the ecu temperature if you are suspicious.  Some models that we make plug-ins for the ECU is fitted inside the engine bay and dont give problems like this.  Your symptoms still sound more like the throttle going in to safety mode.  The reason AC may appear to solve the problem could be related to AC idle step or something else seemingly unrelated.

[KarlSzz]

On 6/10/2021 at 5:07 PM, Adamw said:

I dont think so.  Our ECU's are tested to 70°C continuous and will take more than that short term.  The ECU will typically run about 5-10°C above ambient, so it is unlikely hot enough in the cabin of most cars to cause a problem. You can log the ecu temperature if you are suspicious.  Some models that we make plug-ins for the ECU is fitted inside the engine bay and dont give problems like this.  Your symptoms still sound more like the throttle going in to safety mode.  The reason AC may appear to solve the problem could be related to AC idle step or something else seemingly unrelated.

Strange. My G4X E36X always, and I mean all the time, logs around 70 degrees C when fully warmed up. And it goes up to 80 on a hot day idling. I need advise on this. I use this on an E34, the ECU enclosed in the original metal enclosure. I did not even cover the original waterproof plastic box so the ECU is basically ventilated at all times. I cant imagine what it'll be like for the E36 as their ECUs are tucked away in an even tighter space.

[Adamw]

5 hours ago, KarlSzz said:

I did not even cover the original waterproof plastic box so the ECU is basically ventilated at all times.

Are you sure that doesnt mean it is "ventilated" with hot engine bay air?  I think the idea of being sealed in a box is it is isolated from the engine bay heat.  

We have been selling E36 plug-ins since 2013 with little failures so whatever they reach in their normal enclosure seems to be acceptable.  We only test them long term to 70°C in house.   

[KarlSzz]

3 hours ago, Adamw said:

Are you sure that doesnt mean it is "ventilated" with hot engine bay air?  I think the idea of being sealed in a box is it is isolated from the engine bay heat.  

We have been selling E36 plug-ins since 2013 with little failures so whatever they reach in their normal enclosure seems to be acceptable.  We only test them long term to 70°C in house.   

good to know there's no such incident yet.

 

3 hours ago, Adamw said:

Are you sure that doesnt mean it is "ventilated" with hot engine bay air?  I think the idea of being sealed in a box is it is isolated from the engine bay heat. 

No, the box is isolated from the rest of the engine bay. Exposed to outside air through the vents below the wiper. The heat is generated internally by the ecu (I am quite sure its not a sensor problem, ECU is so hot I couldn't touch it). Other items that share the same box did not see such temperatures. I am wondering if you can help me confirm if this is really normal among E36X ecus, since you mentioned normal operating temp should only be slightly higher than ambient. Thanks.

[Adamw]

The main thing that can generate heat in the ecu case is the ignitors.  Perhaps you have too much dwell and are driving the coils beyond saturation.  

Below is the only long log file I can find from a E36.  ECU temp peaks at about 64deg after 50 mins and is still at 64deg at 68mins.  

[KarlSzz]

23 hours ago, Adamw said:

The main thing that can generate heat in the ecu case is the ignitors.  Perhaps you have too much dwell and are driving the coils beyond saturation.  

Below is the only long log file I can find from a E36.  ECU temp peaks at about 64deg after 50 mins and is still at 64deg at 68mins.  

Thanks for the info. I will check the dwell numbers to find out. Much appreciated.