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ECU doesnt turn off


Guest |249|

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Guest |249|

hi all,

ive got a bit of a strange problem.

my battery is constantly going flat when i leave it over night. what i've noticed is everything controlled by the ECU's power stays on.

the motor for the antenna stays on (i cut the power feed to it since).

my wideband stays on (power feed from brown/blue stripe wire off ECU).

i tried pulling out the main fuse and i noticed my wideband gauge turns off but im not sure about the actual ECU. i still lost power over night when i pulled the main fuse out.

has anyone got any suggestions or things i could try? it started happening quite randomly so i'm a bit stumped as to where the source of the problem is.

the car is an 93 R33 gtst.

any help would be great.

cheers,

joe

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Guest |249|

just a bit more info - the wire that is connected to the wideband is the +12 switched off the ECCS relay. maybe the relay is shagged? would it cause this problem?

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Guest |249|

So I may have a little progress. I unplugged the ECCS relay and connected it to another known working one with no success. Although everything turns off when I pull the ECCS relay off.

I then started the car without the ECCS relay connected and it started but stalled around 5-7 seconds after running and everything else switches off when I take the key out. Every time I pull the key out and try start it again it starts and then stalls.

i dont think its an ECU problem so feel free to delete this thread.

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A large number of technical inquiries are received regarding problems due to incorrect wiring of auxiliary outputs. Incorrect wiring of solenoids and relays to auxiliary outputs can result in the following symptoms:

· ECU not powering down when the key is turned off.

· Accessories such as engine fans coming on when the key is turned off.

· Repeated clicking of relays when the key is turned off (machine gun sound!).

· ECU draining the battery over a few days.

The root cause of these problems is the wiring of hot fed (direct from the battery positive terminal) or ACC fed (key in accessory position) solenoids or relays to ECU auxiliary outputs.

Each auxiliary output basically consists of a low side driver and flywheeling diode. A low side driver is a power transistor that can switch a load to ground. Flywheeling diodes are required for the driving of fast switching devices such as ISC solenoids and VVT solenoids. Flywheeling diodes are also essential for reducing radio interference noise.

Unfortunately, the placement of flywheeling diodes means that if power is applied to auxiliary outputs through a solenoid or relay when the ECU is powered down current will flow through the flywheeling diode causing the ECU to power back up.

As solenoids have some resistance, the current that flows back into the ECU (back feeds) is not usually enough to power the ECU up properly resulting in the ECU powering up and down continuously. This causes unusual behavior by the offending solenoid and possibly other solenoids as its current is switched on and off.

This is taken from the help file. A search on back feeding will give more info.

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Guest |249|

thanks for that mate. but ive had the ECU in for over a year and it just started doing it randomly, i would understand if it happened as i was installing it but it didnt.

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You do not say if this is a plugin ecu or a standalone you wired to the engine.

If it is a plugin, then the ECCS relay is controlled by a component on the base board. This may be faulty and holding the ECCS relay on all the time. If it is a wire in ECU then I cannot think of anything other then what Simon said.

Ray.

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Woops I should never assume!

The ECCS relay is controlled by a transistor on the board.

When 12V is applied to pin 45 it should supply a ground on pin 16.

If this fails when 12V is not present on pin 45 you will still have a ground on pin 16.

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Guest |202|
A large number of technical inquiries are received regarding problems due to incorrect wiring of auxiliary outputs. Incorrect wiring of solenoids and relays to auxiliary outputs can result in the following symptoms:

· ECU not powering down when the key is turned off.

· Accessories such as engine fans coming on when the key is turned off.

· Repeated clicking of relays when the key is turned off (machine gun sound!).

· ECU draining the battery over a few days.

The root cause of these problems is the wiring of hot fed (direct from the battery positive terminal) or ACC fed (key in accessory position) solenoids or relays to ECU auxiliary outputs.

Each auxiliary output basically consists of a low side driver and flywheeling diode. A low side driver is a power transistor that can switch a load to ground. Flywheeling diodes are required for the driving of fast switching devices such as ISC solenoids and VVT solenoids. Flywheeling diodes are also essential for reducing radio interference noise.

Unfortunately, the placement of flywheeling diodes means that if power is applied to auxiliary outputs through a solenoid or relay when the ECU is powered down current will flow through the flywheeling diode causing the ECU to power back up.

As solenoids have some resistance, the current that flows back into the ECU (back feeds) is not usually enough to power the ECU up properly resulting in the ECU powering up and down continuously. This causes unusual behavior by the offending solenoid and possibly other solenoids as its current is switched on and off.

This is taken from the help file. A search on back feeding will give more info.

So Simon, how can this be avoided. What is the prefered wiring methong then for aux outputs?

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  • 1 month later...
Guest |913|

We have spent hours diagnosing our issues with our ECU not powering off. Ours should be simple since we run nothing off any of the Vipec V outputs. Well, we have 2, a rotary switch and the GM Flex fuel. But in our testing we unplugged them. The car is plain and simply NOT powering off. We looked into the adapter box and there are no issues there.

Is the a program there that has a table for "delay for power off time"?

Like above, if we unplug the Vipec and immediately re-plug it in, the car stays powered off. If we start or Ign on and back off, the ECU remains powered up indefinitely.

We tested every pin on the adapter and ECU for ground faults etc but couldnt find any.

Stu Hagen

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Guest |913|
You need to check that pin 16 is not stuck at ground all the time. You should see 12V when key is off and this should then switch to 0V when key is turned on.

Which Pin 16 A or B?. Or this for something else.

Stu

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