everyone is stumped
every single possible test has been run on my engine and everything is fine
it should be starting, and if u leave it for a while it will start for a few seconds but then promptly die

theyve tested compression, replaced sparkies, dropped exhaust, tested spark, everything but it refuses to start properly

theres a few things they havent tried and a few things rong with it
like the water pump is dead and leaking so theres no coolant
they havent tested the air flow meter

but it should still start up right, and idle rough
it completely refuses to start and theyve tried everything possible including auto electrician checking ecu etc

according to their tests it should fire up no problems
any ideas?

Have you tested the fuel pressure? Check everything in the fuel system.

theres fuel getting to the cylinders they reckon
'its getting fuel so it should be starting'
when they were spraying TB cleaner into the air flow meter area it wasnt working but when the lubemo guy sprayed it straight in it worked

It sounds like it s not getting enough fuel. Check Fuel pressure, and check the MAF. Those two things will keep it from running, and both will cause your symptoms.

have you checked the compression?

i would guess that it is ECT sensor, ECU, or low compression...thats if it isnt fuel. i have an almost identical problem, so when you figure it out, let me know. :D

have you checked the compression?

i would guess that it is ECT sensor, ECU, or low compression...thats if it isnt fuel. i have an almost identical problem, so when you figure it out, let me know. :D

He checked the compression, and if it was the sensor he'd get a light, ECU wouldn't even fire at all unless some little wizard changed his maps, so that takes us back to a fuel problem.

He checked the compression, and if it was the sensor he'd get a light, ECU wouldn't even fire at all unless some little wizard changed his maps, so that takes us back to a fuel problem.

well mine isnt a fuel problem and mine problem is almost identical to his. except mine doesnt want to start when the engine is cold...if the sensor is working but not working correctly the ECU will not pick it up, or if there is a short in the wire which is very popular in the earlier Z's, as i have researched, the ECU will not pick that up.

what was the compression at???

im not saying its not a fuel problem but i am saying it could be other things...

Correct K3, it could be a million things, but a good place to start is the fuel and if it's ok, them continue the search.
The rule is, if you have intake and compression the only thing left is ignition and fuel. Now igination could be checked very quick, but fuel problems on a VG30DE engine is a dog of a different breed. If he has 45# fuel pressure after the filter it's ok, if not start looking at pump or filter problems. If it's ok then start checking from that point on. Keep going till you find the problem.

ok i have thought about your problem for a few minutes...

i believe it is surely a fuel related problem. ok, you said when you use like a cold start spray it will crank for a split second but thats it. thats a sign its not getting gas or enough gas. most of those cold start sprays contain ether...ether will act as a fuel for a small amount of time to help start a car that is cold.

do you know how long the car has been sitting? i remember you saying it was shipped to you....after a car sits for a while the fuel pump will cease or corrode. neither is good...in my z31, it had been sitting for a couple years, so my fuel pump would kick on but it would not pump fuel. so i pulled it out and sure enough, you wouldnt believe how corroded this thing was. this is possibly your problem...

also, if it is very cold you could have a frozen fuel line....

also, with out spending anymore money, you can easily check if the engine is getting any fuel what-so-ever...just take a nice size bucket and remove the fuel line from the fuel filter on the inner right fender. put the line coming from the rear of the car into the bucket and have someone turn the key to on and then start. if it isnt spraying any fuel at all, you know you have a block or the fuel pump is not working. i would try this first before going out and buying a fuel pressure checker or anything. if it sprays fuel, it should be coming out pretty powerfully so if its just leaking out you also have a problem.

good luck!!! these are just a couple of ideas...

yep theres plenty of fuel
that thing k3 suggested with pumping the fuel into a bucket worked and theres plenty of fuel in the bucket
i live in australia so its not a cold problem :D
compression was 'fine'
not good but fine

between 130 and 145 on all cyls except 1

the nisscare guy sed the petrol looked funny so he bought 20L of premium and hes gonna try it tomorrow (they flattened the battery and are charging it now)
(btw by premium i mean 98 octane, our premium is 98, our regular is 91)

but heh :\
keep in mind im just trying to get it started and idling, doesnt matter if its not 'running' well
so all the things u guys r suggesting have either been tested or wouldnt really 'prohibit' the engine from idling, itd just idle really rough right?

there seems to be plenty of fuel pressure, everyone is saying so
they dropped the exhaust so theres no clog preventing air from flowing out
but for some reason the aerostart is letting it start up

so it cant b a pressure problem coz even tho the aerostart is pressurized, it should build up and 'clog' and hence the engine would stop again
perhaps an injector problem?

im thinking its a bunch of little problems that usually wouldnt stop the engine from starting but combined theyre doing it, wot dyu guys think?

Having fule flow is one thing, but what was the pressure? If the pressure is below 45lbs then a pump problem. If the pump is good then I'd check the injectors. Have then checked and cleaned. Could be gummed up.

could be fuel injectors gummed up like zgringo said...

the MAF sensor could still cause it not to start if it was reading irrational figures.

on that 6th cylinder, how far was it off compared to the other 5??? low compression in even just one cylinder would cause an engine to be very hard to start. i was told that by a nissan master tech...

you know another thing i was thinking...Power Transistor Unit. it was on recall for all 90's here in the states so im sure that includes 89's over there. check and see if there is a sticker on your hood saying it has been replaced. another thing it could be is dead coil packs. try cleaning your PTU wiring harness with some electric harness cleaner...

ok guys i hope ur not sick of this thread yet coz ive got a big update with lots of fancy words

- disconnected exhaust to make sure there wasnt a clogged cat problem
- tried tow starting to see if getting the engine to start faster than the starter would allow might work, it didnt
- injectors are firing at the right rate according to the ecu and all that
- ecu is fine, I/O is fine, all cylinders have spark except #5
- oil was changed becoz it was contaminated with fuel from all the starts and no running
- water temp sensor was corroded so they fixed that up to make sure it was working
- after the first few cranks it loses manifold vacuum, but its not a exhaust clog
- when its starting on aerostart TB cleaner it starts and idles but only when its sprayed thru the vacuum pickup power booster balance tube thingy, but not when sprayed thru the main air intake
- cam timing must be ok if its idling

ok so heres some questions that might provide some answers

- how come when its started on aerostart when u depress the accelerator, the revs dont increase at all? could it be something to do with that loss of manifold vacuum?

-why doesnt aerostart work when its sprayed thru the main intake?

- theres plenty of fuel pressure and the injectors are switching, so again, why arent the revs picking up when its running on aerostart and u press the accelerator?

k3, the coil packs r fine (they were actually screwed before the lubemobile guy checked them out) he cleaned them and theyre working coz theres spark on all cylinders except #5

according to the auto electrician everything is reading fine so i dont think the MAF is reading weird figures

Were getting closer to the problem. Process of elimitation. Fact when you spray SF through the balance tube it starts. It never well run worth a shit spraying SF into the engine, A/F mixture just isn't there.
2nd Fact when you spray SF into the intake, nada. Now are you talking about in front of the throttle bodys?
If this being the case, put your hand over the intake tube and see if you have vacuum. If not then you have a serious air leak someplace in the intake.
Let's go back to basics.
A engine, all engines work in the same manner, and if something upsets this chain of events it wont run.
1. Intake w/proper A/F mixture
2. Compression
3. Ignition
4. Power (firing)
5. Exhaust
No.1 lets put on hold for a minute.
Now you said you had acceptable compression, so that takes care of No.2
Now No.3. Have anyone checked the timing with a timing light? If not do it now.
No.4 it fires when sprayed with SF
No.5 you said the exhaust is open, so no restrictions.
So we know for fact that No.2,3 an5 are ok.
That leaves us No.1 an 3. No.3 can be checked very easy. When thats done, give me the results.

Umm i dont think i seen someone say this, i know tortzorz said it could be a injector problem.... Have you tried ohming out your injectors?? that could make it do exactly what you are describing....

wouldnt timing have to be ok in order for the car to run in the first place?
if timing was off too much id get bent valves and there cant be bent valves coz i have compression
if its not off enuff to do any damage then it should be starting right

im thinking the main cause of this problem is the loss manifold vacuum, the fact that the pressurized air is allowing it to idle, and the fact that it has no throttle response when its idling makes me think theres a leak somewhere preventing the vacuum from occuring and hence preventing any air from being 'drawn' in

i got this response from someone on the tt.net forums

did you spray on both TB? the balance tube goes to both bank. first, make sure the MAS connector is clean. this will limit you rev. did you remove the fuel rail for some reason? if so, my guess is that you have air in your fuel rail. to get of the air, you have to force the fuel pump to run longer before starting. you can do this with a CONSULT or nProbe. or do it the hard way by shorting the fuel pump relay. good luck!

'air in the fuel rail'
what does that mean?
and extremedrift the autoelec told me the injectors were switching and if there is a brief exhaust note when u leave the car for an extended period, that means there must be fuel getting in right?

but then in comes evil mr.loss-of-vacuum which stops air from being drawn in

anyone have any idea wot might cause this loss?

If the timing of the cams were off it would bend the valves but if after installing a new timing belt and the timing was off a tooth it would cause low compression and lack of proper vacuum. Ignition timing if off can cause loss of power to not runnung at all depending how far it's off.

The fuel pressure has never been checked with a pressure gage. If the fuel pressure is 10# breaking a line wont tell you a thing, other than you have fuel. Having dirty or gummed injectors can stop the flow of fuel also. Just because you have fuel in the tank and it's getting to the filter means nothing unless it's at 45#. Just because you have spark means nothing unless the timing is right. You have to check everything step by step and you'll find the problem, but assuming the something is ok, isn't.

someone may need to confirm this, but if you did have no vacuum the car should still run just not very well. it would act like it wants to die or die. i remember my grandpa had a vacuum hose come loose all the way on his pick-up truck and it still started everytime, it just did not want to stay started. i dunno though...

what was the compression on that cylinder that you said was off???
why isnt that one cylinder firing???
is it the same cylinder that isnt firing and has a lower compression???
if that cylinder isnt firing then you have a dead cylinder...thast not good.

timing is a possiblity...it could be off a fraction, like zgringo said...

how much money have you spent??? might have been cheaper just to buy a new motor...:lol: j/k

actually your compression pressures are off a bit. They are at min specs for the engine and they are out of spec for difference between cylinders. There can be no more than a 12PSI difference between the cylinders. This is most likely caused by worn out rings. I looked all this up on the 300ZX manual.

actually your compression pressures are off a bit. They are at min specs for the engine and they are out of spec for difference between cylinders. There can be no more than a 12PSI difference between the cylinders. This is most likely caused by worn out rings. I looked all this up on the 300ZX manual.

thats wierd, my manual says there can be a 14psi difference between cylinders. they are still within specs so that wouldnt cause it not to run.

id be worried about that one cylinder that was off. how far was it off...what was the compression on it. try pouring a little oil into that particular spark plug hole...that will tell you if it is a worn ring.

but didnt you say you had an 89'...which would be in coordinance with the US 90's...the same 90's popularized by defective valvetrains???

i would check compression again...if 2 cylinders next to each other are off compared to the other 4 then you probably have a blown headgasket in that particular spot. if putting oil in the cylinder raises pressure you have worn piston rings, of neither of those are present then you have a defective valve...
like i said before, a low compressioned cylinder will cause a motor to be very hard to start...you also said you have a dead cylinder because it is not getting spark. both these things together would naturally cause the car not to start...

but it could be other things. damn VG's!!!

The VG isnt that bad.... its alot like a chevy 3.0L V6.

The VG isnt that bad.... its alot like a chevy 3.0L V6.

yeah i know they arent that bad...just all the electronics and wiring kinda leads to undercover problems that are very hard to seak out. this explains why my Z32 manual is longer than any service manual i have ever seen before, that services one make and model.

Remember the 5 steps I listed above. Intake is one of them. Without vacuum no air or fuel can or well inter the engine, so guess what? Won't start. Now if you have a vacuum hose off or a vacuum leak it well make the engine run lean, unless it's a major leak. Thats why I asked him to put his hand over the intake tubes and check for vacuum.

Remember the 5 steps I listed above. Intake is one of them. Without vacuum no air or fuel can or well inter the engine, so guess what? Won't start. Now if you have a vacuum hose off or a vacuum leak it well make the engine run lean, unless it's a major leak. Thats why I asked him to put his hand over the intake tubes and check for vacuum.

ahh...ok. i see now...thanks Al for clarifying that, i asked that a few posts ago. :)

so lets see...

you might have low compression in 1 cylinder...
you dont have spark in another cylinder or the same cylinder...
you dont have vacuum...

wow...good luck dude. keep us updated...whats the latest tortzorz???

the latest is they gave up on wednesday before try any of this and its getting towed to road & track on monday who have worked on 300s before with some good results so hopefully they can find the problem

no updates til at least tuesday tho im afraid
sigh i bought this car in june and i still havent driven it yet :(

the latest is they gave up on wednesday before try any of this and its getting towed to road & track on monday who have worked on 300s before with some good results so hopefully they can find the problem

no updates til at least tuesday tho im afraid
sigh i bought this car in june and i still havent driven it yet :(

i know how you feel...i bought mine in january and i didnt drive it officially until April but it was winter here so whatever...

i hope you get it fixed...good luck!!! keep us posted...

the latest is they gave up on wednesday before try any of this and its getting towed to road & track on monday who have worked on 300s before with some good results so hopefully they can find the problem

no updates til at least tuesday tho im afraid
sigh i bought this car in june and i still havent driven it yet :(

Hang in there....all good things are worth waiting for..