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No ignition on cylinder 4. Burnt up resistor in ECU...

Posted: Wed Jun 10, 2015 6:50 am
by Tengis
RB20DET HCR32.

The blue wire with yellow stripe was grounding out. Ignition timing cyl 4.

There is a resistor (gold black red red) that is the first thing connected to that pin on the ECU that got burnt up. I replaced the resistor and there is still no spark. Took apart a spare igniter and there is a burnt up section that connects to ignition for cylinder 4.

I am posting here because I feel you may have a good working knowledge of the inner workings of the ECU. Do you think replacing this resistor and the igniter would fix the issue? After fixing the grounded out wire and the resistor the only thing left is the igniter. Im afraid to keep trying parts/ecus and burn up a bunch of stuff.

Thoughts? NIStune board should still be good?

Re: No ignition on cylinder 4. Burnt up resistor in ECU...

Posted: Wed Jun 10, 2015 8:10 am
by Matt
Nistune board should still be fine.

The ignition module is in an orange ceramic mini board which is soldered into the ECU main board. Likely you have blown the transistor driver in this module and it would need replacing (from another similar ECU) or you will need a new ECU to change it with

Re: No ignition on cylinder 4. Burnt up resistor in ECU...

Posted: Thu Jun 11, 2015 4:41 am
by Tengis
Would there be any visible burning/damage?

I assume it is the larger of the two orange boards? Any chance just replacing the resistor will work out fine?

Either way, I have an RB26DETT ECU that I may be able to swap parts from if they are the same. I am going to check tomorrow.

Re: No ignition on cylinder 4. Burnt up resistor in ECU...

Posted: Thu Jun 11, 2015 11:09 am
by Matt
IC14 (HRA-75 or similar) in R32 ECU

Not necessarily going to be damage seen. Yes I think you may have damaged this. Resistor took some of the current overload but I've seen a lot of these damaged in customers vehicles due to bad coils or wiring

One from GTR ECU should work. They are a pain to remove and reinstall... heatgun with small nozzle might help

Re: No ignition on cylinder 4. Burnt up resistor in ECU...

Posted: Thu Jun 11, 2015 3:32 pm
by Tengis
Ill see if I can replace it. Ive got a bad GTR ECU and the GTS-T ECU I am trying to repair... worst case scenario is that I still have to buy an ECU.

Re: No ignition on cylinder 4. Burnt up resistor in ECU...

Posted: Fri Jun 12, 2015 6:45 am
by Tengis
Fixed it.

The RB26 ECU and RB20 ECU had different ignition components inside but apparently they are compatible with each other.

Went through about 3 spare coils and two igniters trying to figure out what was wrong before I tracked down the grounded out wire. Then replaced the resistor and the board you mentioned + another coil and it was good to go. Hopefully it doesnt blow the #4 coil again...

Thanks!