no spark need help plz

[agkirtley]

Ok guys ive read some of the other posts on this issue. I have a 91 300zx NA, i got a jdm motor with the ecu. It started running like crap lately, sluggish, no power, delayed throttle response, and it wont idle smoothly or at all sometimes. I changed the fuel filter think maybe it was clogged. I have no spark on my 1 cylinder, i have 12+ volts at the coilpack. I have a spare ptu and ecu so i tried swapping both, and still no spark. Any help would be greatly appreciated

[Ace2cool]

Codes?

[agkirtley]

I have a code 42 only because my motor didnt come with it. My sensor comes in tomorrow, so idk if itll give a new code after is clear

[Ace2cool]

No, that won't make a difference. ECU will stack codes. You are grounding the plug to check spark, yeah? If your problem just magically started, though, your issue is more likely injector related. If you've got 12v at the plug, you're making ground, and no spark, you're missing the fire signal. And since you've already tried ptu and ECU, the issue is wiring related. Or if the injector isn't firing as well, then you could look at the CAS. There's a ton more places to look, just gotta dig in and get dirty.

[agkirtley]

Well I pulled the CAS out and spun it and my injectors are ticking so Idk where to go from there

[Ace2cool]

I'd check the signal wire. Also check your PTU subharness. Just check continuity.

[agkirtley]

What on the ptu am I checking for continuity and what should I check with the signal wire ?

[Ace2cool]

Continuity on both. And I'm talking about the subharness. Check for shorts and open wires.

[agkirtley]

Ok, so I went to work today and came home to start the 300zx grind again. Well now i'm getting stacking codes, 21 and 42. The Fuel Temp sensor i Ordered is a different connector than the one that is on my wiring harness. the spot for it on my block has a plug in it so i'm not sure if they even have them in JDM motors. I've seen a little bit about a few different NIssan Diagnostic software, and i'm curious to know just how much more information they will tell me compared to just going off of my ECU codes. I dont plan on ever getting rid of the car, so i'm wondering if its actually worth investing in. IF so which of the several out there would you recommend?

[Ace2cool]

Conzult is amazing. And honestly, if you buy your own interface cable, the freeware software will be enough to run diagnostics.

[evildky]

You swapped PTU's but did you swap the coil pack? Swap the COP and or spark plug with another cylinder and see if your miss moves with it.

[agkirtley]

This car is about to get scrapped. I overnight the cable, download the software. Try it on 2 laptops and get errors with not being able to get the software to recognize the cord. I pack up my main pc and 32" tv that's it monitor. I get everything installed no errors....but I get literally no information no even battery voltage. I'm assuming my diagnosis port is screwed up too. Any ideas? Oh and I did change coil packs. Locations plugs and until I lost spark in all cylinders it was only #1. My dad said he came out and had tightened up the battery terminals then it wouldn't start. Scrap yard is 5 miles away. It's almost to that point

[evildky]

Have you tested for signal into the ptu? 6 channels in 6 channels out.

[agkirtley]

I havent tested the new one yet so I'll pull it off and test it. I at least have spark On a couple cylinders because it Will fire up. I know I dont have it on 1 and 2

[agkirtley]

Ok, i got Conzult up and running. I tested the PTU, and everything looks good on it. Conzult is saying i have a code 12 mass airflow circuit and a code 21 Ignition Signal Circuit. i checked all my connections on the ignition side of things and everything looks good. Sadly i can't test all the relays and stuff with the freeversion. I'm gonna try cleaning my MAF, as far the the ignition code idk where to go from where i'm at with that.

[agkirtley]

I'm not sure what my MAF voltage is supposed to be at, it barely goes upwhen the car is trying to idle

[agkirtley]

I love Conzult and youtube hahah. There's definitely a problem you can hear around 2,000 RPM with it dropping on its face. I think my MAF voltage is lower than it should be based on a different youtube vid.

[agkirtley]

Sorry to be kinda spamming my own post. I've got everything down to just the MAF code being thrown. I used my multimeter and plugged directly into the plug on it and i'm getting .3 volts, when is start the car the highest ican get it to go is 1 volt thats with me blowing into the front of it. The really weird thing is that if its not plugged into the Y pipe of the intake i get the .3 volts and the car will run for a minute. If i connect the MAF to the Y pipe and test it i'm only getting like .03 volts and the car will fire but not run. I'm thinking my MAF is probably toast, but idk since the voltage does fluctuate. I'd like to be sure before spending 200 on a new MAF

[Ace2cool]

Yeah, the MAF is out of spec. And it's also got the timing advanced about 10*, from what I can tell. Factory spec is 15*BTDC.

[agkirtley]

Well the maf has been replaced and it seems to have fixed that problem. So now my timing is off and adjusting my CAS doesnt seem to change it. If I stab the throttle quickly the timing will drop clear to 5 degrees for a second then start climbing again. Am I adjusting the timing correctly and what would cause it to drop like that

[Ace2cool]

TPS is adjusted a little low. Should be .45V. The ECU will adjust timing if something isn't exactly what it's expecting.

[Ace2cool]

https://z32.wikispaces.com/Ignition+Timing

Also, this guide recommends not using consult alone to check timing.

[agkirtley]

Well sadly when I hook my timing light to my signal wire at the ptu I'm not getting a signal. That cylinder isn't firing either that's how this whole thing started

[Ace2cool]

I've seen people use spark plug wires plugged into coil packs to set timing.

[agkirtley]

I'll have to look into that then. Car is driving me nuts, I miss driving my Z

[agkirtley]

Well I wanna thank everyone for all their input on this issue. We had some bad wiring connections among a bad ptu and maf. She is running again, and I've encountered a new issue. The car has a hesitation when first hitting the throttle or when I shift gears. I'm thinking it is my throttle pos sensor since I was told the voltage looked a bit low. I'll change it out today. Is there anything else that would cause that issue?