power loss, fluctuation C70 2.4t

[zachos]

Hello, I have a problem with C after a year of sitting.
The revs fluctuate, it has less power and jerks.
Errors P1172 and P1175

[scot850]

Check Rick's reply to another owner in this thread. It is where I would suggest to start. Both errors point to fuel trim issues.

viewtopic.php?t=83849

Then there is this one as well. It is also thorough.

https://www.volvoforums.org.uk/forum/te ... 1172/page2

However, here are a few other things I would also suggest as the car has been sitting for a year:

1) Have put fresh gasoline in the tank or ideally drained and filled it? Old gas can cause rough running.

2) do some basic checks like the electrical connections like the one on the MAF. Check for corrosion on the pins. Try running the car with the MAF disconnected to see if it makes any difference and let us know how it goes. This is a test only, not recommended to run on the road like this.

3) Pull out the dipstick and smell it. Does it small like gasoline? If you have had a fuel injector leaking down into the oil it may be thin and causing errors in items like the cam position solenoids.

4) Remove and check the condition of the spark plugs. Do they all show a brownish color or are they black? Check the gaps are at 0.028" and that the surfaces of where the coil packs are contacting are not corroded.

5) Check the air box that you have not had any unwanted visitors into the filter box while standing. Same with the exhaust. Does it sound normal?

Good Luck!

Neil.

[zachos]

hello, so it was started on old petrol, but since then about 40L of fresh petrol has been poured in, MAF cleaned maybe slightly better but the problem has not gone away, the engine oil replaced with a new one looks ok, the spark plugs and coils look ok, the air filter is new, the air filter housing is ok, the exhaust may be slightly leaky

[Vova585]

Great work. I would suggest to find scanner and see what the fuel pressure sensor, engine coolant sensor and map are showing. Looking at fuel trims also can provide you with helpful info on what your car is doing (are trims lean? Or rich?).
If such is not an option, you can always remove injectors and find some good "pahn" to clean them for you and test on the stand for flow and spray pattern. It would likely be not too terribly expensive and better than cleaning it with wynns method(connecting cleaner to injector rail and run car on it). Good luck. Sława Polsce