cannot solve this for nuthin'

[xxninja]

man guys i cannot solve this problem with my car that i been having all summer with my national
well i cannot figure out why when i step on the gas and the engine goes into load, the car is making a metal pinging sound even at 5 psi of boost !
now i changed the wires and plugs(ac73ts) and ignition system 3 (caspers, wells)different times and it wont solve it, i got a new o2, and it is around 780 on the scanmaster even when it does it.
im not throwing any codes and i have have good voltage and vacuum.
i went so far as to replace the headgaskets , maf, get a new fuel pump n hotwire it and buy new injectors with a chip to match

my only last ideas could be the cam sensor,egr , or possibly timing chain. whats the chances a bad cam sensor could be that out of time to make a metal pinging sound.
i know alot of people seem to think it's boost related, but it happens at 2-5 pounds of boost just putting load on the engine and i am not rich or lean on the 02s. i run 93 or 94 octance always.

it seems to run fine just running around town, but when u go to get on the boost it starts to do it.
i dont understand this at all, its a summer car with 60k original on it, stock turbo and just has a cold air kit on it, adj regulator & wastegate

this is some of my scanmaster stats........
car idles at 700 smoothly
temp : 170
no codes what so ever
o2 : 780 as high at 802
maf : 8 at idle
tps : .42 / iac :20 at idle

i just wonder if any1 had a little insight or any ideas or what 2 try
or look at .i'd appreciate any comments from your past experiences or problems
thanx guys

 

[Warp6]

try running some race gas (110 octane at least) and see if it still does it

 

[TurboJim]

My bet is HG blown between cyls, or a dead cam. I'd lean more toward the HG.

 

[xxninja]

welp fellas thanx f0r the adivce
but i've run 108 in it an it still does it and 5 pounds of boost
and as for the head gaskets i just replaced them in march when i had my heads freshened up and i havent even run over 8 pounds of boost
so i dont think i could have blown them and there is no visible signs of a blown gasket, i had this problem on the factory gaskets as well

hmm i wonder if maybe the timning chain could be missing a few teeth
i guess i should run a compression test just to get some data on the car
im starting to think on the more serious side of problems, as in a wiped lobe or bad timing chain, i just figured it wasnt mechanical because it has 60k on it
are nationals prone to mechanical failures in those 2 areas?

thanx
the aggrovation continues heh

brian

 

[turbo buicks]

you said you are runnin ac73ts plugs.. wouldnt this be a hot plug. the ac44ts is for stock cars and the ac43ts is for modded cars. most here run 43's. i would think 73 would be a hot plug. try looing to see if anything is touching under load such as downpipe hitting header, etc. although the cam sensor controls injector timing not ignition timing you could get a cam sensor tool from any major ($24) and set your cam sensor correctly. also with the car running depress the diaphragm under the round EGR thing. i think the idle will change and if not its a bad EGR. listen to your car closely at idle. if the timing chain is missing it should be apparent. put a pipe on the water pump (be careful of the pulley) and listen in the pipe. if something is making noise loudly and then you listen in the pipe when its on another part of the engine away from the water pump/timing chain area then you can see the timing chain is making the noise and needs fixing. my cars chain was/is so loud you car hear it at idle w/o a pipe and its loud w/a pipe. i think i need a new tensioner and cam button. this is all i can think of right now

 

[2QWIK4U]

My GN did the same thing a couple of years ago and finally found it to be the bronze valve guides were to tight.I mean they were really tight once the egine was warm and they expanded.This caused the puck to flutter very badly and make a pinging/rattle sound especially under 10 psi.I would have to tighten the puck very tight to stop it.