Will not start!! - literally tried everything

[aretwodetwo]

I'm really confused with my Z now and ive been through every trouble shooting tactic this week to get this thing started and everything checks out ok. (background) bought the car from an old dude and the car has not ran for 15 years, new turbos, new trans, rebuilt engine, replaced all connectors asociating with the engine, I first tried starting up the car and wouldnt start gave me code 11 and checked the cas by rotating and checking for injector tick and got nothing so i replaced the cas and attempted a 2nd start, got code 21 and pulled apart the PTU harness and cleaned it and checked resistance between the ECU and the PTU and the coil packs and the PTU and got 0.2-0.5 ohms for each reading which is OK in my book, the car struggles to turn on now but i have Nissan datascan and shows the fuel pump is working, i have an inline psi gauge that reads about 40-45psi when the fuel rail is primed, injectors passed resistance test, all between 10-15 ohms, new ngk platinum spark plugs, checked the PTU and it works fine and is the newer style PTU and passed all resistance tests, if you can name anything ive probably done it. she still struggles to turn on, i turn the key to start and it just cranks and if i give it gas the rpms raise a little bit to maybe 300 rpm and then i can let go of the key and it stumbles really bad and if i keep my foot steady about half way down on the gas pedal it will keep running barely around 250-350rpm according to nissan data scan and even though my foot is steady it will immediately die after about two seconds of that very low rough stumbling idle. i have no idea what is going on at all.

[rgregoryb]

have you checked all the grounds? Take them loose clean them and reinstall. 1 at rear of plenum passenger side. One past injector #6 near firewall again on plenum. Also on that goes to frame near AC compressor

[aretwodetwo]

okay, i checked the two that are on the back of the plenum and disconnected those and reconnected them and cleaned them til they shined, ill get under the car and remove and clean the body ground, ive seen it and know exactly where it is.

[ArmedAviator]

Did you drain the old gas and fill it with new gas? Old gas will not combust well, if at all.

[aretwodetwo]

checked the chassis ground over by the ac and removed it and cleaned it and installed it with a new bolt and washer and it didnt help at all, i drained the old gas a week ago before starting the car and put 11 gallons of 91 octane in, and while i had the top of the tank open i took a microfiber and just lightly wiped the dirt off the bottom of the tank. i also tried to adjust the iacv both ways, full clockwise and full counterclockwise and it didnt help at all.

[nissanfreak12]

What were the exact numbers for the injectors?

Are you sure the timing was set correctly?

Have you tried adjusting the CAS and starting the car?

Are you sure the injectors are actually spraying fuel? Are the plugs wet when you attempt to start the car?

Are you 100% sure the the injector and coil packs are on the correct cylinder?

[aretwodetwo]

all the exact same reading for the injectors, i know the spec is between 10-15 ohms and i tested them individually and they were all exactly the same. around 12.2 ohms if i recall, today i tested the harness at the ecu for each injector so it checks the wiring and got 12.2-12.4 for each one.

i took off the timing covers and lined up the crank with the cams and counted the teeth and it was perfect, did it again yesterday to verify

i tried adjusting the cas and starting the car and it did nothing.

my cylinder number 1 spark plug was black with carbon and it was fresh when i first put them in at the start of the rebuild... so i assume atleast i have spark and fuel if the plugs are black.

rechecked each wire to the injector and the coil pack for each cylinder by using the EWD and the color code for the wires and they all checked out fine.

[nissanfreak12]

Specs should be 10-14 not 10-15---This is just for reference in case someone else is looking for the specs.
example 14.2 would equal a bad injector, but this isn't the case for you.

Is your TPS adjusted correctly? Try unplugging it and see if there is a difference.

When you had the engine apart, did you use any towels or something to block the passages so no pieces would fall into the engine? Its an easy mistake, has happened recently on another post.

Have you tried unplugging the MAF and starting it?

Since it is a rebuild, compression could be low(rings set incorrectly), try adding some oil in the combustion chamber to see if that helps.

[evildky]

Have you checked the physical timing of the cams and crank? Is the indexing tang on the drivers side exhaust cam in tact and locating the cas properly? It sounds ot me that you either lack compression doe to a physical timing issue or that the ignition is very weak or very late.

[rgregoryb]

Fuel filter?

[z.Leinbach]

are the injectors leaking into the cylinders? you say it runs more so when the trottle is open. seems to me as a super rich condition, along with the blackened plugs.. sence all your specs are inline. try looking at the basics. Air + fuel = fire to much of either. leads to running issues. to much fuel makes for blackened plugs, to much air makes for a bubbled and melted plug tip.

may seem basic. but sometimes we spend to much time looking at the complicated crap.. and dismiss the basics. i have a intermiten running issue where i had a lopey stumbing like idle that i have traced to fuel.. i was running 92 made the problem more pronounced, switched to 89. made it smoother. now im at 87 (regualar) its the most smooth ive had the car running, (cylinders and plugs are now clean an carbon free as well). hope this helps.

[DCaff300ZX]

are the injectors leaking into the cylinders? you say it runs more so when the trottle is open. seems to me as a super rich condition, along with the blackened plugs.. sence all your specs are inline. try looking at the basics. Air + fuel = fire to much of either. leads to running issues. to much fuel makes for blackened plugs, to much air makes for a bubbled and melted plug tip.

may seem basic. but sometimes we spend to much time looking at the complicated crap.. and dismiss the basics. i have a intermiten running issue where i had a lopey stumbing like idle that i have traced to fuel.. i was running 92 made the problem more pronounced, switched to 89. made it smoother. now im at 87 (regualar) its the most smooth ive had the car running, (cylinders and plugs are now clean an carbon free as well). hope this helps.

Very good thinking here, definitely worth looking into and a definite problem with our cars and their complicated nature. That's why I've found that using the fsm for tests and their procedure often works best either at problem solution, or telling you when the problem has moved into the Twilight Zone arena.
As for the problem under discussion I agree with the assessment of potentially leaking injector o-ring(s) or even failed injector(s) possibly causing the blackened state of the plugs, especially so quickly.
Hope a new line of thought helps!

[budget300zx]

Could also be a massive vacuum leak which is probably the most common problem with any car that's been freshly rebuilt.

Id start there then rent compression gauge from your local parts store and post your results .

[z.Leinbach]

Any update??