Rb25 R32 Unique Electrical Problem

[Traah221]

Alright gents, here's a new one for me, from what I've seen on the forums at least. So, I have no spark in any cylinder for all intents and purpose. I pulled out the multimeter and started at the ECU, checking 12V Power from all my Spark Feeds (pins 101, 103, 105, 110, 112, 114) as well as 12V ECCS inputs (pins 49, 58, 59, 109). All were between 12V-13V EXCEPT for 103, Cyl. 2 Spark, which would come in at around 5V-6V occasionally. I went about checking my ECU spark earths (Pins 1, 2, 3, 11, 12, 13) as well as Main ECU grounds (pins 50, 60, 107, 108, 116) and all checked out as earthing for 12V-13V. So, with the exception of one faulty feed, I had 12V flowing from the ECU to the Ignitor Chip, in theory, but when checking the inbound side of the chip, I had no response on every pin that was supposed to be 12V. So...my question is What Gives? Are just my Spark feeds cut somewhere between the ECU and the Chip? Or am I looking at a faulty ECU?

Recap: I have good 12V and earths on all but 1 pin FROM the ECU, but at the plug to the ignitor chip, I have no power.

Attached is the pinout guide I've been using. It says the Grounds are pins 101, 103, 105, 110, 112, and 114, But I'm getting a Solid 12V from them, and a ground at 1, 2, 3, 11, 12, 13 and 10.

[blind_elk]

Which ECU are you using? Which RB25DET - S1 or S2? Because S2 has the ignitor built into the coil, and doesn't need the ignitor box.

Have you checked for continuity (0 ohms) along each of the wires between ECU and ignitor chip?

[Traah221]

Series 1 RB25DET with Series 1 ECU and RB20 Harness, Ignitor Chip, Coil harness, and Coils.

00.3 Ohms resistance across all 6 feeds from the ECU to the Chip. But should those be 12V feeds? Because the multimeter shows them as grounds, not 12V feeds.

[Traah221]

Alright, final check shows me that at the 3 pin grey plug that goes to the coil harness, as well as the 6 pin plug that goes into the Ignition chip, I don't have 12V anywhere, tested all 9 pins, no 12V feed from the ECU with key On, Off, or Cranking. Am I looking at a faulty ECU hopefully?

[blind_elk]

When measuring resistance, voltage is irrelevant.

Pins 101, 103, 105, 110, 112, 114 are for INJECTORS, not spark.

In general, the ECU does not supply power to anything, but provides a switch to earth.

By my reading of the circuit diagram, each coil gets power via a relay to pin 2. Pin 3 goes to earth. Pin 1 goes back to the ignitor module, where it eventually gets switched to earth through the ECU. Plus an earth from the coil side of the ignitor (7-wire side).

[Traah221]

Yeah, I went through my post and a few more diagrams and realized that mistake. I'm aware resistance deals in Ohms and not Voltage, I first checked all 6 wires from ECU up to the Ignition chip for Resistance (Measuring 00.3 Ohms on all 6) and THEN checked for 12V coming out of any of the 6 wires to the Ignition Chip, and the 3 to the grey plug next to it.

So, you're saying that the earth readings at the ECU are correct, so where would my 12V feed to the ignition chip be coming from?