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

[Famine]

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]

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]

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]

is it not firing at all or does it fire occasionally?

 

[Famine]

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]

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]

have u taken off the rocker cover and checked the valve spring??? buicks have a tendancy to break valve springs

 

[Famine]

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,

 

[sixshooter]

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.

 

[whisky]

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.