changed everything! 304 still missing...

[speed__demond]

okay so had a miss for months, slowly got worse and worse and now its just plain crap!
the idle is smooth but every 5-10 seconds it misses and when I accelerate its splutters and misses all over the place.

changed:
plugs twice, leads, cap, button, coil.
manifold gaskets. all vac hoses. and the water temp sensor.
changed to my tuned memcal and still has that miss so it aint that.
and just put in brandnew injectors.

im sick of trying everything and getting no results, anybody here have the same issue before?

 

[someguy360]

Fuel Pump, Fuel Filter, Fuel Pressure Regulator......could be causing fuel pressure fluctuations/issues.

Have you checked compression and vacuum (using a vacuum gauge)? (many don't do this anymore but a compression/vacuum tests can tell you so much about your engine before spending unnecessary money and can easily help you track down lots of issues)

 

[hotrod]

yip that's sounds like a Holden to me. keep spending u find it eventually .

 

[speed__demond]

also replaced oxy...

don't have acsess to a a guage and never used one either...
it was showing vac leak error last time I checked but I tried the wd40 trick and found one of the injectors leaking so replaced.. still issue..

ill drive it tomorrow and see if it throws vac code again, but ive replaced everything so I don't see how it would still...

 

[someguy360]

also replaced oxy...

don't have acsess to a a guage and never used one either...
it was showing vac leak error last time I checked but I tried the wd40 trick and found one of the injectors leaking so replaced.. still issue..

ill drive it tomorrow and see if it throws vac code again, but ive replaced everything so I don't see how it would still...

Not all vacuum leaks are easy to find, not only is it important to find vac leaks but its important to make sure the engine is making enough vacuum and also compression to run the engine properly, you were lucky to get any code for a vac leak, usually you don't get anything.

you also have to remember a vac leak can come from anywhere, a hose in the manifold, your vacuum ball in the front bumper, your climate control/hvac system behind the dash, your brake booster or your map sensor a vac gauge will show this much easier than trying to spray WD40 around the place (it can be as simple as a tiny hairline crack that isn't visible to the eye on any vacuum line in the car that can cause issues)

Don't rely solely on error codes when diagnosing an engine.

I would be doing a compression and vac test before anything else (they are cheap, there is a billion and 1 resources online on how to do it) and it could save you spending any more money.


Also check your timing, you can spend all the money in the world on ignition gear, but if the timing isn't right or the compression and vacuum isn't right it will run like ass no matter what.

Basic compression and vacuum gauges are cheap, buy both, its essential if you plan to work on cars yourself. (And a timing light is a good thing to have with older engines like 304's)

 

[mr j-man]

Can u tell what bank its missing on?

A vac, comp and leak down tests should've been done first up then progress to the ignition system.

How are your plugs? Are they fouling....

 

[speed__demond]

nah the plugs are clean, nope cant tell what bank..
could the dizzy itself cause this problem? I really hope not...
its on duelfuel so not fuel related.
really feels like vac.. ill have to look up how to test it, can it point me to where the vac leak is if I do test it?

 

[someguy360]

really feels like vac.. ill have to look up how to test it, can it point me to where the vac leak is if I do test it?

Can't really point you to exactly where but gives you proof that its not ignition, fuel pressure or anything else so you don't have to spend any more money

You really need to combine a vac test with a compression test, as low compression cause vacuum issues too.

 

[ari666]

you also have to remember a vac leak can come from anywhere, a hose in the manifold, your vacuum ball in the front bumper, your climate control/hvac system behind the dash, your brake booster or your map sensor

soooo many people forget about the dipstick.

but more to the point, is your MAF clean?

 

[someguy360]

but more to the point, is your MAF clean?

No MAF on the Pre VT 304's

Only a MAP