P0305 code

**Cibargar69** · 12-11-2013

OK..here I am again. Earlier posts by me on this subject are now moot. Quick synopsis:

2000 GPGT 3.8 ~230k miles
New plugs
New coils
New ICM
New wires

p0305 code is now showing

Compression shows ~60 on cylinder 5
Compression shows ~70 on cylinder 3

Car was running OK earlier, with minor engine knock. A more than normal acceleration created louder knocking, which then activated the idiot light.

Injectors swapped between 3 and 5 did NOT migrate the problem.

I have earlier seen this problem mysteriously vanish for some days....but again appear. OK, short of extensive (and expensive) engine exploration i.e. ripping it down, is there anything that I should also consider?

Don't want to flush my GP...

Thanks,
Joe

**dsmuts** · 12-11-2013

That compression is super low. Check all the cylinder's compression and see if the gauge just may be reading wrong.

**Cibargar69** · 12-12-2013

TY dsmuts. This was a running compression test to isolate for weak valve springs. The 100 PSI spec is for a "static" compression test (fuel and ignition disabled and tested while cranking). I'm getting closer and closer to the toilet handle daily...

**Cibargar69** · 01-27-2014

OK...It's been a bit but here's the latest. Idiot light is ghosting....one day on...and then it's off. When idiot is on P305 is reported. And usually when on, loud lifter noise is heard.

This is a short vid to hear the tap ...> http://youtu.be/b3FT7U64Ukw WHEN IT'S FAILING...

I changed oil recently, and some metalics were found, but with 230k I kinda expect that. Last oil change done with 1qt MMO about 1k ago. Right now, car is normal...no light..no tap..but I am thinking about replacing the lifter(s).

Your thoughts???????

**Scottydoggs** · 01-27-2014

does sound like a sticking lifter and that would make sense with the metal you found. do you still have the metal you found? was it copper colored, or silver? was it chunks? or just grit?

mine will tick in the summer time if im over due on my oil change, but only like 3 ticks (once in a while) then it stops, oil change fixes it again.

if its not a sticking lifter, like in the bore. and its bleeding off (loosing pressure over night) GM says its ok if it stops with in a minute or two.

**Cibargar69** · 01-27-2014

Unfortunately, no I do not have nor seen the reported matalics. Oil Change was done by my mechanic as the car was there for a starter repair and I had him change the oil while it was up on the lift. The tap is not seasonal, nor time-of-day dependent. I have another mechanic that I saw earlier today. I barter my I.T. services with him, so any labor will be reasonable. Only other suggestion is an engine swap...i.e. get one from a junk yard. I think that replacing a lifter and any related components is a safer bet (and cheaper) then rolling the dice on a absolute unknown.

**Scottydoggs** · 01-27-2014

if its been suggested to get a used engine by a trusted mechanic, may as well do it. your vid there dont sound health at all really.

those n/a engines can be found with low miles and for about 300 bucks. not so bad really. change the lim gaskets and a few other little up grades and your back on the road.

this is a super charged lim, but your n/a lim has these 2 holes too, seal them off and the car will never have a chance to hydro lock again. print it out have your friend plug these holes for ya. http://www.grandprixforums.net/showthread.php?t=46931