DjDecibel Posted April 26, 2023 Report Share Posted April 26, 2023 Hello, i own a '97 R33 GTS-T with RB25 engine, it had a 23710 21U00 ecu replaced with a GTRLink (pcb rev V1.7) the cars starts and runs but not fine, it is a lot rich of fuel and does a lot of black smoke from the exhaust. also the power is not enough. checking the fuses i found that the fuse number 8 (which should be the engine management fuse) keeps blowing.. and now here start my question: is it normal as the ecu is not original or there's a short somewhere in the sensors or harness? or is it a normal thing? Thank you! Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 27, 2023 Report Share Posted April 27, 2023 It sounds like you are going to have to investigate the wiring a bit to determine the cause of the blown fuse. Fuse 8 supplies 12V to ECU pins 49/59 & 58, Our ecu doesnt have pin 109 connected. There is not a lot of wiring between the ECCS relay and the ecu so I think it is less likely to be in this area. Fuse 8 also feeds a supply out to the engine bay for the oxy probe, idle valve, boost solenoid and VTC solenoid if fitted, so I think it is probably more likely in this part of the loom. One test you can do to rule out a short in the ecu case or similar - Unplug the ecu, replace fuse 8, switch on Ign, connect pin 16 in the ecu loom plug to ground with a scrap piece of wire or similar, this will switch on the ECCE relay. If your fuse blows with that test then look at the wiring after the ecu. If the fuse no longer blows with ecu unplugged then I will try to come up with some further suggestions of what to check next. Quote Link to comment Share on other sites More sharing options...
DjDecibel Posted April 28, 2023 Author Report Share Posted April 28, 2023 i'll do the testing in the next days as i don't have the car here... but how is possible that the car has a perfect idle if the 12+ voltage is not feeding the IAC valve? Quote Link to comment Share on other sites More sharing options...
koracing Posted May 2, 2023 Report Share Posted May 2, 2023 A car can idle fine without an IAC if it's getting the right amount of air to idle. Quote Link to comment Share on other sites More sharing options...
DjDecibel Posted May 3, 2023 Author Report Share Posted May 3, 2023 On 4/27/2023 at 4:18 AM, Adamw said: It sounds like you are going to have to investigate the wiring a bit to determine the cause of the blown fuse. Fuse 8 supplies 12V to ECU pins 49/59 & 58, Our ecu doesnt have pin 109 connected. There is not a lot of wiring between the ECCS relay and the ecu so I think it is less likely to be in this area. Fuse 8 also feeds a supply out to the engine bay for the oxy probe, idle valve, boost solenoid and VTC solenoid if fitted, so I think it is probably more likely in this part of the loom. One test you can do to rule out a short in the ecu case or similar - Unplug the ecu, replace fuse 8, switch on Ign, connect pin 16 in the ecu loom plug to ground with a scrap piece of wire or similar, this will switch on the ECCE relay. If your fuse blows with that test then look at the wiring after the ecu. If the fuse no longer blows with ecu unplugged then I will try to come up with some further suggestions of what to check next. I did the testing you said. removing the ecu and Grounding the pin16 the fuse does NOT blow i then opened the ecu and I saw a burn diode What can I do? Quote Link to comment Share on other sites More sharing options...
koracing Posted May 4, 2023 Report Share Posted May 4, 2023 You'll need to email [email protected] and request instructions to return the ecu for repair. Quote Link to comment Share on other sites More sharing options...
DjDecibel Posted May 4, 2023 Author Report Share Posted May 4, 2023 5 hours ago, koracing said: You'll need to email [email protected] and request instructions to return the ecu for repair. Ok, and what can cause this type damage? If the problem is still in the car can damage the ecu again Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 4, 2023 Report Share Posted May 4, 2023 That diode is only the flywheel diode for the idle valve, it is hugely overrated and when the engine is off it doesnt even have any current flowing through it - let alone enough current to make it explode like that. The most likely scenario that could cause that would be reverse polarity = i.e the battery has been connected backwards at some stage or jumper leads backwards etc. I think also the fact you still have a short when you plug the ecu in now would suggest that big mosfet behind the diode is fried too. Quote Link to comment Share on other sites More sharing options...
DjDecibel Posted May 4, 2023 Author Report Share Posted May 4, 2023 i already bought the car with that problem, so i think the previous owner did something wrong.. so the only solution is to send the ecu to repair? i live in italy Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 4, 2023 Report Share Posted May 4, 2023 Email tech support as suggested earlier, they will give instructions on where it needs to go, most likely our Spain or UK office. Quote Link to comment Share on other sites More sharing options...
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