New World Datsuns...

Got injector pulse on all 6?

Just stopped by Harbor Freight tonight and got their 39 dollar noid light set. Should make it easier.

Confirmed. 1 and 2 have no injector pulse. I didn't check the rest given the symptoms, I think it's pretty obvious. So now I'm going to scour the fsm and find out what controls the injectors. It's getting spark definitely, which should mean the CAS is working. I'm not sure how the fuel is controlled. Checking for stuff I may not have plugged in, but haven't found anything so far.

Ok, doing the tests, I'm not getting continuity through terminal 1 of the 6 block that goes to the injectors. I'm getting battery voltage at the injectors, but those have to switch to ground to fire. The 1 spot on the injector harness going to the ecu block is the problem. I hate reading wiring diagrams, but it also mentions Air Regulator (-) 1 and Air Regulator (+) 2 next to the 6 block connection on the wiring diagram for troubleshooting injector system.

I'm thinking that means I have a break in the 1 wire, which would indicate it can't find a ground to switch for the ECU???? Or something to that effect. Anyway, test is put spot 1 to each injector wire on the ECU connector block, and all of them have good or crappy continuity with 3,4,5, and 6, but none have continuity with spot 1. Which means something is screwed up. Unless having the connector disconnected to test is why. Fuck. I HATE WIRING!!! I'm so crossed up now I'm giving it a rest for the night.

Short of it is, the injectors are getting power both sides like they're supposed to, but they're not getting a ground signal to fire, hence the issue.

After thinking on it, I found that negative is common to all the injectors, seeing as it's a batch fire. So basically, now I need to trace the 1 connector up from the 6 plug, and find where the 6 wires join into it and either find the bad crimp there, or a broken wire somewhere in between. If I fix that, it should allow the ground to complete, which will then cycle the injectors and IAC normally. That's my working theory anyway.

It's not sequential? Well, huh.

You know, I'm not sure how that works. I know the KA in the truck is multi-port-fuel-injection but batch fire also. So is the old 280zx turbo. I guess maybe the Neo Rb25s and what not are sequential maybe or Nissan just figured batch fire worked well enough, who cares? Rbs made decent power. They've definitely used it for years.

So all the power feeds and all the grounds are together?

Most 'modern' engines have a common power feed but separate grounds at the ECM.

The test procedure is checking for continuity between terminal 1 and all the other terminals for each injector on the ECU harness (101, 103, 105, etc) And given they all have the same 12 volt signal, the ECU grounds each one whenever it needs to fire, and since they're batch and firing together, all 6 injector spots go to 1, as it shows all of them tied together on the diagram. I only have the engine manual though, not the electrical schematic. Either way I know 1 is a problem so I'll unmask that and see what I find. If nothing, I'll go another route.

Interesting

Motherfucker. So when you check for continuity between terminal 1 on the 6 block connector near the front of the engine, ignition has to be on. Surprise surprise, I have continuity. Back to the drawing board.

What I've established so far is the CAS works. I removed it and spun by hand, both IAC triggers and spark triggers. However, no injector pulse. Reading lots of other forums for similar no injector pulse, haven't found squat for resolution. Theoretically, if the CAS triggers spark, it shouldn't have any issue triggering injectors.

The last guy said the fix was crappy connectors near the wheelwell, super helpful. Anyway, digging into information, I know it's something simple, but yeah, not sure yet. ECU possibly, but a few other threads that have the same symptoms said they tried another ECU, same thing.

This is the link I used, seems to be correct from cross-checking. https://forums.hybridz.org/topic/90784- ... -datsun-z/

Anyone else got any ideas?

Keith knows, he's just being a dick and making you work for it.

Can you backprobe your noid light at the ECM? That would eliminate all the wiring.

OK, the thing I would check now is if you have power to everything when the key is in the start position, remove the wire that excites the starter and see if you still have power to everything in the start position, maybe you already have done this.

I found one injector ground that wasn't grounded. Grounded it. No change. Got depressed and angry. Finally called a guy I know and told him cash money to make this thing work. He's coming by Sunday. I'll let you all know what we find. If nothing, I'll buy the $700 harness from wiring specialties. Hoping I can make this one work. Everything works, except injector pulse. I think it's a ground issue, but damn if I can find it.

Can you post the wiring diagram?

Unfortunately, this is what I have. https://wiki.r31skylineclub.com/images/ ... inouts.jpg

I have the engine FSM for the RB, but it doesn't include wiring diagrams. I have basic wiring diagrams in the engine manual, but not the old spaghetti line pullouts like in the '83 FSM I have. Just began wondering about the oil pressure switch. I remember Honda's having the needed before the fuel pump was operational. Not sure if mine is plugged in, I'll have to go check. I think it is, but you never know.

I don't know how newer engines work, but my diesel engines need oil pressure for them to start, but if I unplug the wire from the sender/sensor it thinks it has oil pressure when I turn the key on because there is no ground as I removed the wire.

So if you unplug all the injectors, then turn on the ignition to "run", what do you have at each injector connector? 1 12v and one open? Or 1 gnd and one open?

Wiring Specialties posts the pinouts here:https://www.wiringspecialties.com/ecu-pinouts/

R32 GTR FSM, page 778 on are the wiring guides https://nicoclub.com/FSM/Skyline/rb/R32 ... Manual.pdf

DUDE, LAECAON, THANK YOU!!! I couldn't find that for what ever reason. I had the engine manual, but didn't give the whole schematics with wire colors, the guy who's coming over was already pissed about that. I quote, "You're doing it the hardest way possible and you went balls deep." Lol, this will undoubtedly help. I have the wiring specialties instruction manual for their wiring harness (which I don't have....yet) and I've been comparing it too. I know there has to be just something stupid not in the right place or not connected, just haven't been able to figure out what.

I have pins 43 and 10 with continuity at the ecu, which is odd to me, because one is a ground, the other is the start signal that's supposed to go to the starter. Which maybe the momentary positive while cranking is supposed to operate like that because Nissan loves to switch grounds and whatnot.

If I connect pin 18, fuel pump relay, I get a 3/4 knock sensor code on the computer. If I leave it disconnected, its 5/5, all good.

I'll report back today, we'll see what comes up. Worst case, something is fucked, I get a new harness. Best case, the engine will run today.