:'( car still wont start - Page 2

tortzorz · 02-02-2005, 06:53 AM

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?

Zgringo · 02-02-2005, 10:06 AM

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.

k3smostwanted · 02-02-2005, 02:46 PM

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...

j/k

Hodo · 02-02-2005, 05:28 PM

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.

k3smostwanted · 02-02-2005, 08:17 PM

Quote:

Originally Posted by Hodo

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!!!

Hodo · 02-02-2005, 11:18 PM

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

k3smostwanted · 02-03-2005, 04:08 PM

Quote:

Originally Posted by Hodo

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.

Zgringo · 02-03-2005, 05:15 PM

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.

k3smostwanted · 02-03-2005, 05:35 PM

Quote:

Originally Posted by Zgringo

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???

tortzorz · 02-03-2005, 10:59 PM

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

k3smostwanted · 02-03-2005, 11:01 PM

Quote:

Originally Posted by 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

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...

Zgringo · 02-05-2005, 01:22 AM

Quote:

Originally Posted by 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

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

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