I have a 1998 S70 non-turbo, and the idle is very rough. I have to rev a lot (manual transmission) to launch without stalling. At higher rpm, the engine appears to run smooth and I do not see a lack of power. I had a cylinder misfire last year, and saw very quickly that it was a wire (of no. 2 cylinder) and I changed the wires and plugs and solved that problem. This time around, I checked the wires (visually) and they appeared ok. I will try a resistance check on the weekend. I changed the cap and rotor and put in new plugs, and that did not change anything. It appears to be cylinder no. 2 again that is not firing at low rpm. I am burning oil, and I know that fouls the plugs, so I keep an eye on them.

I am very discouraged. If there is a simple fix, please let me know...

 

I would do a compression test.

 

You think I have a burnt valve?

 

That is my thoughts.

 

I finally took the car to a garage, as I had an oil leak also.
Cylinder 1: 70psi
Cylinder 2: 0psi
Cylinder 3: 190 psi
Cylinder 4: 190 psi
Cylinder 5: 190 psi

The mechanic figured that I had a burnt valve in cylinder 2, and that the head gasket was blown between 1 & 2. I don't remember which seal was leaking, but to fix the problem (for the oil leak) would have been a $350 job. Anyway, there was enough evidence for me to conclude that my car had reached the end of its useful life.

Thank you for your insight and kind replies.

 

There is no way I would retire it for that little cost. I need a lot more than that on my 98 S70 and I just keep fixing everything that was neglected before.

 

The valve job and oil leak was on top of everything else that was in need of repair, in light of everything that I already fixed in the last 18 months of ownership. It needs a new windshield, new brakes all around, new shocks all around, a new cv joint, a new O2 sensor (and possibly a new cat, again...). That's what I know about. Then there are the surprises...I was fed up. Maybe if someone had given me the car I would feel a little different. Probably not.

 

What causes a cat to go bad?

Hey Untuned, I'm with you. Sounds like the repairs would cost more than you can get another car for. Part it out or put it on CL for $500.

 

my friend and i just completed a head cylinder job for a 98 s70 due to overheating and warping the head. But now that everything is in place, the engine turns over but does not turn on totally, injectors wasnt opening for fuel. Is this mean my fuel/ignitor ECU is Bad? before i go out there and buy the ECU, just figure i asked? thanks.

 

I was commuting 220 km per day to work, and after a month of ownership, the cat literally fell off the car. When the car was on the lift, the mechanic pointed out an oil leak that appeared to be coming from the crank seal. Anyway, I realized that I was losing a lot of oil, probably a liter per tank of gas. After the crank seal was changed, I was still losing oil, about half of what I was losing before. That was the oil that the engine was burning, and after some research on this site, I figured that my valve stem seals needed to be replaced. Doing the valve stem seals, if indeed that was the case, was more money than I wanted to spend on a car I just purchased and that I just dropped $1500 on in repairs. Anyway, burning oil is apparently a good way to foul your O2 sensor and your cat. After the cat was changed, I put in a new O2 sensor, but it was just a matter of time before that fouled up again too. I suspect that my O2 sensor was no longer working properly (again), and the additional fuel being injected contributed to carbon buildup in cylinder #2, which kept an exhaust valve slightly open, enough to burn it out. Just a guess though. My mechanical skills are very limited.

So I sold it for parts for $500 to guy that parts out s70's and 850's. Apparently there is a lot of demand...