TougeSR20Kid

Hey everyone, so I have an s13 with an RB20 in it and recently it dropped cylinder #2. I ran the gambit of tests on it to figure out that it was that the injector was not getting signal from the ecu to fire - One of the leads had power and the other lead had like some random 8v signal that didnt register as power or ground. When I tested another plug it registered with power at one and then fluctuating signal of power and ground on the other. I dunno it was weird but anyways I know thats how it is suppose to be because cylinder #1 is working. So basically I have found that there is clearly something off with either the wiring or the ecu for the injector circuit for cylinder #2

My question is has anyone seen an ECU fail like this before? Where only one cylinder injector circuit fails?

Seems pretty random to me. I'm leaning more to the ecu being at fault for two reasons. 1) the wiring gets a signal from on both sides of the plug if there was a break in the wiring it would not register anything on at least one of the pins 2) the wiring harness is only 3 years old (wiring specialties) so it almost seems logical the problem is with the 23 year old part and not the 3 year old part.

Any and all help is much appreciated, thank you ahead of time

In the interest of saving time with the "what tests did you run" question:
- compression test
- new plugs
- checked for spark
- replaced the injector (several times with new ones)

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Namaste mother f**ker

TougeSR20Kid

Well I figured it out on my own in case anyone else has this problem....

The RB20det ecu along with the series 1 RB25 ecu have dedicated circuits for each injector this means that there is one power and then they fire with a controlled ground. Each ground is controlled by the ecu so the ecu tells each injector when to fire, how long to fire, how often, etc. In other ECU's for other models and other companies there aren't dedicated circuits they are on shared circuits. In other words cyl 1 and 4 will be on one circuit and 2 and 5 on another and 3 and 6 on another.

So the answer is yes the circuitry for an injector can fail in the ECU and in my situation did

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Namaste mother f**ker