Ok I am out of ideas here. I have one last idea and I'm praying that is not the case.
I am very capable and this is the first time a car has made me feel so stupid.
Bought Car as a project (big regret) and it did not run. PO said the NATs system was the cause of not running. Didnt care as I plan to rebuild the whole car (winter project)
Got the NATs removed by an UPREV dealer - No start.
Did some testing between ECU and sensors and found no com between relay. Changed Relay - No start. Dismantled IPDM and found severe corrosion so swapped it out and car fired up.

Here is where it gets bad. Car barely idles, misfires like crazy. Gets slightly better as car reaches temp but still running horribly.
Changed the following:
Catalytic Converters - Replaced with Test Pipes. Passenger Side was only 1/4 left inside.
Changed Upstream 02 Sensors, Tuned out Downstream 02.
Changed Valve Covers
Changed Coil Packs (verified placement of connections)
Changed Plugs
Changed Cam and Crank Position Sensors
Changed Knock Sensor and Harness
Changed MAF
Changed all 6 Injectors
Changed Vacuum Hoses and PCV
Tested Fuel Pressure (Key on Not running - waiting for fitting to check while running)
Added additional Grounds
Compression Test is 180psi in all 6

Nothing has changed in the way the car runs throughout the process.

Only RED FLAG I am seeing is Ignition timing at 68degrees for cylinder one prior to starting key on engine off

Previous owner states he did timing chain right before selling, I am thinking its out of time. I have a spare engine ready to drop in. Wanted to verify all else first.

Any ideas? I can rebuild an LS engine in a day and built a 650hp 6.0 Diesel but can't get this little Z to run and its driving me nuts.

 

I feel your pain.Same year same problem. replaced everything. We think ours is blown. 200k miles.Where did you get your spare engine? I'm contemplating ditching the car but may swap the engine with a JDM if I can find a reasonable shop. I don't have the tools or space to do a swap anymore.This is my son's car. Cold compression test is 180 like yours but it eats oil so bad since day one. Oil rings are shot I believe.

 

It boggles my mind when people just replace things to replace them hoping it will fix the problem.
No one knows how to diagnose the problem properly anymore

 

Well that's awfully helpful of you. Seeing as each of the items I have replaced were due anyway it wasn't exactly the parts shotgun...
Valve Covers - Leaking
Coil Packs - Mismatched
Plugs - Probably older than me
MAF - Replaced as last one had a cracked connector
CATs - Seeing different readings in banks, turned out one was blown out and the other nearly clogged
ECM - WAS locked
Cam and Crank Sensors - Typical Wear Items
Knock Sensor - Gave a code, found cut in main harness
Fuel Pressure Adaptor - 50 bucks for peace of mind
Injectors - Definitely had an injector issue from the Live Data

Glad you can hop on here and take time out of your day to bash other people rather than being helpful. I'm typically quite capable with diagnostics and have NEVER worked on a Nissan before and if you are the SUPER MECHANIC you make yourself out to be you would know that all manufacturers have their own quirks. First time I get stumped I reach out for help and have to deal with Fudds like you. Great work kiddo keep it up!

 

If the PO did indeed replace the timing set, that would be the 1st place I would check. To know for sure about the timing situation, you would to hook up a scope between the cam and crank sensor to capture data and compare with a known good. I suspect your guess is correct though, and the engine is out of time, if it's severely out of time, then you may also have valve to piston contact (never good).

But it could also be things like bad gas or swapped coil pack plugs. Since you fired the parts canon and replaced a ton of sensors and coils, I want to caution that only OEM sensors should be used. Putting aftermarket typically leads to causing more problems.
-Icer

 

When I took on the project I knew the car was a basket case and had a ton of issues, this is typically my specialty.
I found 2 cars on marketplace identical, both had "electrical issues" One was a manual that was ragged out with 17 previous owners, the other was a 2 owner auto in phenomenal shape with no title from an estate auction.

Got them both for 4k dollars.

Last project was a retired 2014 Tahoe I got at police auction for 2000 bucks. Had a horrible misfire, engine knocking, and oil pressure issues, not to mention the slew of cosmetics. I rebuilt the top end of the motor, changed the oil pump, added some nice tasteful mods and sold it for 10k dollars with 180k miles. Some people will get on here and act superior but would be the same people that try to buy spark plugs for diesels.

My other project is a 2004 Excursion 6.0 Built putting out right around 650hp with no expense spared.

 

Hey there!

I have ruled out gas, and the coil packs being swapped. I've checked it with a bore scope and stethoscope and I'm certain the pistons and valves are not trying to share a bed. I haven't had any luck finding anyone to share their Timing advance before starting to see if mine is far off. Judging by the rest of the repairs it is certainly possible the timing job was botched and it's off by ever so much. Seeing as I have a donor car with a solid engine in it I may just swap them out. Then I can get the old engine on a stand and check timing. As far as sensors go I I only used high quality parts, I don't buy cheap.

 

Remove the engine and drop in the spare and enjoy the car…

then go an re-do timing on the original engine … truth is stranger than fiction

 

I agree with Beall and it looks like you're already leaning in that direction. It should be a simple plug and play swap since it's an earlier year Z33 (no special caveats on the engine/harness between 6MT vs. AT, aside from the trans harness and swapping out flexplate for flywheel).

Last year I helped a friend of mine with a similar issue on his Audi B5 S4, he messed with the secondary cam timing chains while replacing some half-moon seals on the cylinder heads. During that work, he got the intake cam out of time by a single tooth. The engine ran fine to the naked eye, but the computer was not happy. It sat in that state for two years until his smog check was due (CA). Long story short, I stepped in and helped him sort out the issue among others while we were in there. Car runs better than it ever did since he purchased it. I must say, those Audi/VW engines are really unique, you really need to read the shop manual in detail, you can't make any assumptions based on prior experience with Japanese or Domestic brands. For example, I discovered the timing chain link count for the cams is different between bank 1 and bank 2. You would think it would be the same/symmetrical (mirror image of each side), but it's not and I think this assumption is what screwed my buddy over.

Cheers!
-Icer

 

Hey thanks for the feedback. I was leaning towards a timing issue. My main reason for being confused is that when the car is up to operating temp and has ran for a few minutes it idles and runs fairly smooth. I guess this could be due to the variable valve timing and electronic controls. I have NEVER been as stumped by a car as I am this one. The whole point of getting into a little Z car was because I felt they were simple to work on. My plan was to restore and build for turbo. If I can't even get the stock car to run I'm afraid I may need to find a different platform.

 

Had the same problem, stumped for a few weeks I had a severe vacuum leak on my sons when we first got it. Of course it happened after we bought it but it was a 125k car. I did the same thing you did. I bought a cheap smoke machine off Amazon and it was a vacuum leak.Plastic intake pipe was cracked sucking air. Fixed that, 4 years later the engine was shot so I sold it.cheap, didn't want to do an engine swap. on a car that has some rust.but he replaced the car with a nice low mile one.