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RB25 plugin ecu problem


K3N
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I recently purchased a link g4+ plugin ecu for my r33 rb25. Got it tuned and running perfectly for the past 3 weeks. Yesterday my wideband suddenly registered rich 10.0:1 afr ( dead time went up bcoz of low voltage ) and voltage on +12v internal shows 8.9x volts. Ignition on the check engine light is dimmed and the Motorsport functions are all no working. Upon checking the ecu is outputting around 9v on pin 49 & pin 59 with the eccs relay unplugged and ignition on. Any ideas? 

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1 hour ago, K3N said:

Upon checking the ecu is outputting around 9v on pin 49 & pin 59 with the eccs relay unplugged and ignition on.

Pin 49 & 59 are the main power supply to the ecu so any voltage showing on those pins with the ECCS relay removed will be due to a back feed through the ECU.  Most likely from the boost valve or idle valve coil if they are powered separately from the ECCS relay.

A more helpful test would be check voltage on pin 49 or 59 with the ECCS relay connected and ignition on.  Also while you are at it, check voltage between 49 & 10 (main ground).  report back what you see there.  The ECCS relay contacts are becoming a relatively common failure in the skylines so that would be my first thought. 

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Just checked. Pin 49 and 59 registered around 9v with eccs relay plugged in and ign on. Voltage between 49 and 10 also registered the same voltage around 9.

Additional info: pin 3 & pin 2 on ecss relay socket registered 12v. Pin 5 registered 9v.IMG_20180523_143036.thumb.jpg.51605feb0956ea73655076c56a2c43fd.jpgIMG_20180523_143016.thumb.jpg.494c9192c3b7927a532c61d536ea3934.jpg

 

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So what u r saying is that without the eccs relay plugged in the ecu pin 49&59 registering 9v is normal? 

Is jumping the relay pin 3 & 5 with short wire ok for troubleshooting? I'm worried I might cause damage to the ecu.

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18 minutes ago, K3N said:

So what u r saying is that without the eccs relay plugged in the ecu pin 49&59 registering 9v is normal? 

Yes, that may happen since you have the key on, but relay out, some of the accesories will be powered up (such as boost valve etc), but the ECU is not powered up.  The 12V from those auxilaries can backfeed through diodes etc in the ecu then "come out" of the pin 49/59.

 

23 minutes ago, K3N said:

Is jumping the relay pin 3 & 5 with short wire ok for troubleshooting? I'm worried I might cause damage to the ecu.

Yep, perfectly fine to do that and that will tell you if that relay is the problem or not.  Just make sure that you do bridge 3&5 and not 1&2.  bridging 1&2 will pop a fuse. 

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1 hour ago, Adamw said:

Yes, that may happen since you have the key on, but relay out, some of the accesories will be powered up (such as boost valve etc), but the ECU is not powered up.  The 12V from those auxilaries can backfeed through diodes etc in the ecu then "come out" of the pin 49/59.

 

Yep, perfectly fine to do that and that will tell you if that relay is the problem or not.  Just make sure that you do bridge 3&5 and not 1&2.  bridging 1&2 will pop a fuse. 

 Alright. Will try it out tomorrow and let u know.

One more thing. Is the check light supposed to light up during ign on and goes off when engine running like oem? 

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  • 3 years later...
On 5/24/2018 at 5:12 AM, K3N said:

Update: jumped the eccs relay car start right up all functioning. So confirmed relay fault. Thank Adamw Simon

Hello, I know this thread is about three years old, but it sounds like I‘m having the same problem.

Could you tell me where the ECCS relay is located in the Nissan Skyline R33 GTS-T?

I thougt it should be in the passenger side footwell near the ECU, but there only two blue relays and acc. to the parts catalogue it is an „ignition coil relay“ and an „EDI (electonic gas/fuel injection) relay“, correct?

Thank you very much in advance.

Maik

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