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Chipped pistons options

no, it should not be pegged under light acceleration. a real boost gauge would help more though.

scangauges: aeroforce or scanmaster.
 


Scanmaster? nevermind searched it......**** its more then the scanguage. :( So is ZZp the cheapest for the scanguage?

Could this be a boost bypass valve issue? I don't even know what pressure they are good for stock? I guess i should be searching the ish eh?
 
unless the BBV is getting stuck closed then i dont see how that could be causing it. pop the hood and see if the diaphram moves when you goose the throttle.
 
Bio248 said:
unless the BBV is getting stuck closed then i dont see how that could be causing it. pop the hood and see if the diaphram moves when you goose the throttle.
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drive by wire FTL. OK well I goosed it and my boost guage is jumping up, damn near pegging so I got a problem for sure. The diaphragm linkage is all the way up, I can push it down,but can't see if it's moving from in the car. Damnit
 
Bio248 said:
phone a friend.
Click to expand...

I have no friends....well not around here. OK this is what I see, the actuator moves down when the ignition is turned off, it goes up at startup. If I push it down while idling it starts making some racket. I'd assume it's working? or should I just bypass the solenoid and run it off vaccum once?
 


bypass it for a sec and see what it does. dont leave the line open and create a vacuum leak cause then itll run like crap for sure.
 
ok I'll try that tomorrow, went for another ride and the boost appears to be under control better,but will still verify the actuator operation is correct.

I pinpointed my noise my trans is whining like a *****, especially in 1st. well off to work for me. Thanks for the help bio:th_thumbsup-wink:
 
well a little update with the GTP if anyone gives a ****.

Trans whine was from fluid, ended up adding a few more quarts to get it at full while running. It's been awhile since I worked on a car that needed to be running to get the proper fluid level...OOPS

Boost appears to be fine as I can drive it around and stay out of boost with no problems. I think it was a freak occurance when it pegged under light load.

I finally got a code and of course I'm back to misfire on cyl #3. The plugs are brand new and the wires are less then a year old. So, I picked up some new coils and reset the computer. About to go on another long drive to see how it responds.

Being that this car has 115K miles on it, coils seemed like a good start. Are there any known ways to test them? My misfire only comes on under moderate load/boost. I can actually do short bursts of acceleration at times with no misfire sensed or felt. I still need to find/order a scanguage to monitor this thing better.
 
some of these cars like to have misfire issues for no reason. it could be anything in the electrical system or even a chipped piston. i know mine misfired at idle all the time, but never when i was driving around (didn't have a cam either).

i would have swapped the coil packs first to see if the misfire moved. if that didnt work i would have swapped injectors to see if it moved then. its possible that youre getting an injector that is dying.
 
You're right I was thinking that when I changed out the coil packs "maybe I should just swap them first" But, then I said **** it the damn car is a GM and it has 115K miles on it.

I went on a longer drive and the misfire is still there under load. At idle it's smooth, actually pulls decent below 3500rpms, but once you start getting around 3-3500rpms it becomes evident something is amiss. I was thinking injectors also. I'll swap the #3 injector and see what happens with the misfire then.
 


I put the OEM coil packs back on and swapped #3 and #5 injectors. I still get a #3 misfire. I'm going to swap around the coil packs and pray tonight. I'm getting a bit frustrated now. Oh and any attempt at going above 3500rpms is met with severe bog and then eventual knock.

On edit: I went through all the plugs and gapped them on the tighter side, verified all the wires are intact and seated. No noticeable improvement was felt. Also WTF would cause the supercharger to flutter while under boost? It literally sounds like its fluttering on and off very quickly, not like the usual consistent whine. I'm going to see if one of the local dealers will do me a favor and check this thing out. I'm lost right now especially after the injector swap had no change. I'll try the coils again and see if it improves, if not I might just man up and take it to the dealer to get it scanned.
 
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for some reason it sounds like you have a clogged cat. im not reading back to read your mods or what youve done, but no power and bogging is usually a restriction in the system. is it making excessive boost and knocking?
 
Bio248 said:
for some reason it sounds like you have a clogged cat. im not reading back to read your mods or what youve done, but no power and bogging is usually a restriction in the system. is it making excessive boost and knocking?
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The problem is it actually pulls pretty good til I hit 3000-3500rpms, then it bogs down, loses power and eventually knocks(which I did twice and said enough of that) The car is bone stock outside of the L67 pistons and ARP rod bolts it is all OEM.

Also are these cars susposed to stop revving at 3500rpms in park? I was slowly revving it up last night in the driveway listening for unloaded noises and noticed it just stops revving.

I still need a real boost gauge and that scan gauge would be great too for troubleshooting purposes. Basically the symptoms are it can't rev past 3500rpms,begins to misfire around 3000rpms under load,will knock if I just keep trying to accelerate, the trans also gets finicky between the 1-2 shift when this is going on.

I guess pulling my cat is the next option.....great:(
 
yeah, we have a rev limiter in park and neutral when not moving. its somewhere in the 4000 RPM range.

honestly i would invest in a 3" downpipe just because it opens up the car so much in comparison to stock and if your cat is clogged then youll be solving the problem at the same time.
 
OK good to know.

I was looking at the ZZp off road downpipe. With that I'll need the O2 simulators,but no more cat worries. I'm gonna drop the cat today or tomorrow when time permits. Any suggestions on a downpipe are greatly appreciated.
 


OK I'll look into the 3" offroad pipe w/O2 sims and appriopate bungs for my 04. I guess I should have just got headers from the get go:(
 
Re: Chipped pistons UPDATE!

Well I finally got the cat pipe dropped and found it full of aluminum:th_depressed: Once i saw this I knew what my problem was, so I gutted the bastard. After a thorough gut job I bolted her back up and went for a drive. :th_thumbsup-wink: She breathes once again. No more supercharger flutter, no more misfire, no more revving problems. Amazingly it sounds good too, not much louder then stock which was a pleasant surprise. Now just to take care of the SES light and continue breaking it in.

Thanks again Bio for the help:th_thumbsup-wink:
 
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