How To Service a RB25 Ignitor

How To Service a RB25 Ignitor


Problems with spark or having no spark at all can be a difficult thing to deal with in your engine swap. Now consider that your engine is available in the Japanese Domestic Market only, and this frustration can become even more severe. Engines like the RB25DET found in the Nissan Skyline R33, which we’ll be working on today in our How To Service a RB25 Ignitor guide.

Today we’ll be looking at how to test a RB25 ignitor as well as service or possibly fix any problems with your ignitor. This is part 2 of our three part series on How To Service your RB25 Ignition System. Also, if you already know your ignitor is dead and do not care to test or try and fix it, check out our How To Install a J30 Ignitor in a RB25 Guide.

How To Wire a J30 Ignitor
How To Wire a J30 Ignitor

If you are having a spark issue, check Part 1 first and make sure you have voltage at the following points;

  • ECCS Relay harness – 12 volts
  • ECCS Relay PIN 5 – 12 volts when switched
  • Ignition Relay plug – 12 volts
  • Ignition Relay PIN 5 – 12 volts when switched.

First you will need to remove the RB25 ignitor from your engine, unplug it from the engine harness and then unbolt the RB25 ignitor from the engine. With the ignitor in hand, you should be measuring the output side of the ignitor, which has a total of six pins.

This How To Service a RB25 Ignitor guide already assumes you already know your RB25 ignitor is bad. If you are looking to see how to test a RB25 ignitor, that’s covered in Part 1 of our How to Service your RB25 Ignition System. If you are not sure, and want a quick recap to test the wiring of your RB25 ignition system, read on. If you know your RB25 Ignitor is bad already, move onto the last section.

Now reconnect the seven pin engine harness to your ignitor, and you will be measuring for resistance between the six pin connector and each of the ignition coils in question.

How To Wire a RB25 Igniter


Make sure you have the seven pin connector or the engine bay connector firmly seated before unplugging your ignition coils and testing for continuity.

J30 Ignitor Install – How To


Unplug each one of the three pin ignition coils leading to your engine, and you will be measuring PIN 3 on each coil plug for continuity to one of the six pins on your ignitor.

How To Wire a RB25DET Ignitor
How To Wire a RB25DET Ignitor

Measure for continuity between each one of these wires from the six pin side of the ignitor to PIN 1 of the ignition coils. Each pin should test good to your ignition coils, or more specifically PIN 1 of the ignition coils. If you do not have continuity here, replace your injector harness.

Next in our How To Service a RB25 Ignitor you will be checking the ECCS relay as well as the Ignition Relay for continuity at PIN 1 and PIN 3 for a low reference signal.


How To Service a RB25 Ignitor


Remove your ignitor completely and carefully use a chisel to crack the black upper case of the Power transistor unit. When you have the first crack opened, gently pry open using a flat head until you can lift and breakaway the plastic insert that secures the Ignitor closed.


With any luck, you should be able to carefully strip away the plastic insert, revealing the inside of your RB25 ignitor.

how-to-service-a-rb25-ignitor-1 how-to-service-a-rb25-ignitor-2

There’s a film of electrical gel that you must remove before you can repair the RB ignitor internals. Carefully examine your ignitor for any broken wires or problem areas, that would lead to you believe the connection is broken.

Our RB ignitor clearly had one pin pulled off, you will need to peel this entire layer away to access the broken wire underneath. This is a time consuming method, so take care not to damage any other wires or connections as you attempt to clean off the board as best as possible. Using your fingers is often best, as the tacky material can be rolled up like a carpet if done right.


Once you have your wire repaired, you can snap your RB25 ignitor back together and back back on the road! If your repairs do not seem to have solved your ignition issues, try upgrading to a J30 ignitor instead!



    • Hi Tommy, yes you can upgrade to MSD coils at the same time and it’s a great choice if you don’t mind locating your coils elsewhere in your engine bay. We’ll be dusting off another one of our writeups and showing you how to upgrade to MSD coils in a RB.

      Thanks for commenting.