Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

one piston not firing, not the injector, possibly burnt valve or head gasket?

Famine

New Member
Joined
Jun 15, 2005
Messages
195
Reaction score
3
Points
0
Age
33
Members Ride
VR Berlina V6
The mechanic was about to do an injector service on my car, he ran a few tests and came to the conclusion that the injectors were fine, indicating that its either the head gasket or a burnt valve. Its only one piston thats not firing, so it looks like I'm up for big money, unless I can do it myself (with my dads help). Hes pretty mechanically minded, and used to repair old petrol pumps back in the day, would it be a very hard job to do? Is it just a matter of unbolting parts? Wouldnt want to ruin it just to save some money.
 

hako

Donating Member
Joined
Aug 1, 2004
Messages
8,020
Reaction score
87
Points
48
Age
77
Location
Toowoomba SE QLD
Members Ride
VS11 BT1 V6
I'd imagine the mechanic has performed a compression test to check the cylinder pressures and found one to be way down. So that means one head has to come off to find out if its a simple gasket failure or a burnt valve. Best case scenario is that its just the gasket gone which will cost a set of gaskets and a cylinder head skim ....say under $200. Worst case is a burnt valve and seat in which case it would be easier to get a 2nd hand good head...plus gaskets etc...say $500. All doing it yourself and its not rocket science - buy a workshop manual however (Gregorys ~$40). The mechanic will charge (at a rough guess) $600 to $800 for his labour minimum on top of those figures. So thats what you could save in exchange for getting greasy, losing skin and blood and practicing swearing/cursing. The other bonus if you do it yourself is that you end up feeling more confident of what you can do....and that can be a great feeling. Your old man also would probably feel pretty stoked that you asked for his help. Good Luck.
 

Famine

New Member
Joined
Jun 15, 2005
Messages
195
Reaction score
3
Points
0
Age
33
Members Ride
VR Berlina V6
Thanks hako, yeh he did a compression test and thats what he told me. Ill look into buying one of those workshop manuals, just to get into my head roghly how the engine goes together, lol.

Hopefully its just the gasket. Thanks for your help :)
 

JD

Donating Member
Joined
Aug 18, 2006
Messages
1,716
Reaction score
25
Points
0
Age
34
Location
Deep South, SA
Website
www.ccgm.au.tt
Members Ride
1.6L Turbo Holden Croooooooooooze
is it not firing at all or does it fire occasionally?
 

Famine

New Member
Joined
Jun 15, 2005
Messages
195
Reaction score
3
Points
0
Age
33
Members Ride
VR Berlina V6
From what I can see, it doesnt fire at all. If I take out the lead that goes to the injector, it doesnt make a difference to the idle of the motor, however if I take out the injecter lead on another cylinder, it makes a big difference, and the idle gets very rough. As it is now, the idle is a bit rough due to the one cylinder not firing at all.
 

fitzy2005

New Member
Joined
Jul 27, 2005
Messages
1,971
Reaction score
11
Points
0
Location
Wide Bay, Queensland
Members Ride
VY S2 Berlina
Famine said:
Thanks hako, yeh he did a compression test and thats what he told me. Ill look into buying one of those workshop manuals, just to get into my head roghly how the engine goes together, lol.

Hopefully its just the gasket. Thanks for your help :)
i didnt really have a clue what i was doing when i put my worked heads on, had a go and its back n the road, it was fairly easy to do, just make sure u got a torque wrench handy
 

Boonz

Donating Member
Joined
Jul 27, 2005
Messages
4,042
Reaction score
46
Points
0
Age
32
Location
berri, south australia
Members Ride
green 355 VG ute
have u taken off the rocker cover and checked the valve spring??? buicks have a tendancy to break valve springs
 

Famine

New Member
Joined
Jun 15, 2005
Messages
195
Reaction score
3
Points
0
Age
33
Members Ride
VR Berlina V6
No I havnt, no idea if the mechanic did either. Ill check it though, if its worth a shot. Oh and thats good to know fitzy2005, :D
 

sixshooter

New Member
Joined
Jul 22, 2005
Messages
2,061
Reaction score
28
Points
0
Members Ride
2x VS
Before you start ripping your motor apart or going to a mechanic to get ripped off.... I take it you have tried swapping coils and leads around to check if the problem shifts to another cylinder ? Just make sure you've got the coil packs labeled so you know what goes where !

A friend of mine brought his car around for me to look at...said it was running really rough on LPG... the mechanic he usually takes his car to said his LPG convertor was stuffed and needed replacing...cost $500 +labor... I stuck my head under his bonnet and jiggled the leads about and started it up. The crossfiring that was occuring between the leads was attrocious, $50 later and a new set of leads and the car was running fine.

Beware of mechanics looking for a sucker !

And make sure you disconnect the battery before playing around with the electrical side of things.
 
W

whisky

Guest
sixshooter said:
Before you start ripping your motor apart or going to a mechanic to get ripped off.... I take it you have tried swapping coils and leads around to check if the problem shifts to another cylinder ? Just make sure you've got the coil packs labeled so you know what goes where !

A friend of mine brought his car around for me to look at...said it was running really rough on LPG... the mechanic he usually takes his car to said his LPG convertor was stuffed and needed replacing...cost $500 +labor... I stuck my head under his bonnet and jiggled the leads about and started it up. The crossfiring that was occuring between the leads was attrocious, $50 later and a new set of leads and the car was running fine.

Beware of mechanics looking for a sucker !

And make sure you disconnect the battery before playing around with the electrical side of things.
If it's down on compression on one cylinder, it's not going to be the lead or the coilpack.
 
Top