RB20 not firing on cylinder #4 HELP!

Discuss the RB20, RB25 and RB26 series engines.
Paradox
Posts: 102
Joined: Thu Nov 07, 2002 12:41 pm
Car: Cars, computers...

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I have some serious wiring issues. I am not getting spark on #4 cylinder. I have swapped coilpacks and KNOW this is good. I put in another injector and it is known good.

I took my multimeter and did some tests, maybe they did something maybe not, I am not the person you want doing wiring...

I took the multimeter from the the E to the - (the 2 outside pins) on the coilpack harness clip. All of the cylinders except #4 read 1. #4 read 1.7 or so which means to me there is some extra juice running into this coilpack. This was done with key on and ohm meter on 20

I tested the continuity of each wire from all 6 plugs on coilpack to the ignitor and to the corresponding cylinder, no issues (1&6, 2&5, 3&4).

I tested the pins in the ignitor and each of them read 1 except #4 (again 1.7)

I am lost. It seems that it is before the ignitor (I have 2 and swapped the other in, similar results (1.4 or 5 I think)

If it is a power source somewhere before the ignitor, it would seem to me that it couldn't single out #4 cylinder, right?

I stripped the plastic/tape from the #4 wires to coilpack and looked for exposed wires, nothing. I even popped the 3 wires out of the plug (breaking the plug because it is so brittle).

I took the coilpack and plug off #3 and put it on #4 leaving nothing on #3. When running, I removed the #3 coilpack from cylinder 4 and it ran worse, proving the injector is ok.

What would cause the ignitor to send too much power just to #4? This is baffling. I have 2 ignitors (both Z32) and are wired with ground running across to injector side center (using 7 pin plug on that side and 6 pin plug on coilpack side).

ANY ideas? I am at my wit's end. It starts up fine, just misses on #4 and that is a pretty important part...running on all 6 cylinders. I have done compression tests (prior to install) and the cylinders are all close to each other, and it did run on #4 when I put #3 coilpack and wire on #4. The signal from the ignitor is the only clue I have.

How should I use my multimeter? This is probably so simple, but I am clueless.


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SullivanRacing06
Posts: 1974
Joined: Sat Apr 21, 2007 8:45 am
Car: r32 gtst, 06 350z, r32 gtr, rs4 steaga, 04 350z, f350/6bt
Location: Gainesville

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try n wiggle the wires going in/out of the ignitor are loose? try idling the car n wiggling the wires to see if that helps, that was the problem on the r32 i just had in my shop

Paradox
Posts: 102
Joined: Thu Nov 07, 2002 12:41 pm
Car: Cars, computers...

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I tested the pins coming out of the ignitor, so I know that cannot be the problem (well I assume it). It is just the #4 that reads different from the other 5.

ANyone else have any ideas?

Paradox
Posts: 102
Joined: Thu Nov 07, 2002 12:41 pm
Car: Cars, computers...

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My issue was ECU...I had 1 and bought one, I assumed new one was good...well, you know what they say about assume...

It runs great now!


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