So I've learnt a lot today, if I keep going like this I might be able to replace the head in the future when I got the knowledge, or I might fuck that one up too, whatever though, you live and you learn (and you lose money)

So these are the issues that I have with my lovely 1997 Volvo 850 at the moment, it's the only thing I think about right now, mainly because I'm worried for its future.

Issues:

1. AC dead

2. Oil consumption, excessive smoke after a long idle and a bit of gas

3. After replacing the PCV-system, the “lambda” light is on in the dash, indicating an error with some sensor, maybe vacuum hose related?

Reading “OBD-II” Codes:

So the car has an OBD-II port, but it doesn’t work like a modern one, it works more like the OBD-I system that was in the older 1993-1995 volvo 850. (This applies to the Siemens Fenix 5.2 engine management, and probably some other system too, in other variants the OBD-II prot works like a new one) So to read error codes on the Fenix 5.2 ECU you will need:

1. A Button/switch

2. 3 wires

3. A 12V LED

The switch will go between pin 5 and pin X, pin X is the pin corresponding to the module you are getting the codes from. The pin X wire then goes to the LED and acts as a ground, the positive side of the LED connects to pin 16. The pin X corresponding modules are:

Pin 3: The Engine ECU itself, this is the important one

Pin 6: The climate control, my AC bad so maybe there's something here

Pin 7: ABS, Immobilizer, Speedo, SRS, etc. But you need a volvo scan tool here.

Pin 13: Cruise control, but I don’t have that sooooo

Here's a diagram

the blue wire going to pin 6 is the one that controls which module you are getting codes from, so the one in the diagram is getting codes from the ECC. which is the climate control.

Now the reason that I suddenly need to read my codes is that some sensor has gone mad after I replaced the PCV system, when I reconnected everything the Lambda light in the dash was on, and then driving around it stutters and cuts fuel under acceleration. So I really hope that there is a code to read so I can see what sensor is acting up, hopefully it’s just the connection to it that needs to be checked...

The oil consumption:

This one is the big annoying one, the symptoms are:

Oil is being used, this is obvious from the blue smoke and oil level changing.

After idling for a little while, revving the engine will produce a large cloud of smoke out the exhaust, internet and good man Daniel says this is bad valve stem seals (good thing i only have 10 to replace then and not 20 xd)

There’s smoke coming out the dipstick tube, and oil is to be found on the top of the head, presumably because its coming up through the spark plug holes. Blow By? Or can this also be because of bad valve stem seals, I don't think so..

Story goes that I saw smoke coming out the dipstick tube, and internet said that this is likely a bad PCV system, so without doing the glove test where you put a glove over the oil filling hole and see if it inflates I go and buy a new PCV system. The PCV system i pulled out was surprisingly clean… So it was probably fine and that car would have likely passed the glove test if I did it before replacing, dumb me. So now to fix the issue I will have to take the head off, and rebuild it, this also means replacing timing belt and so on, and with timing belt replacement I should probably change the water pump too then, it quickly becomes expensive. And what if it’s excessive blow by, then I have to take the pistons out and replace the rings, maybe the whole piston? I don’t really know.

AC being dead

Not a big deal cause I’m used to not having AC, but basically, when you turn it on you can hear it engage, and then disengage constantly, so it’s probably leaky and dropped all it’s contents somewhere, this issue is the least of my worries.

Thanks for reading about my troubled engine, the rest of the car is in immaculate though, with little to no rust, and a perfect interior, and a three full service books, documenting all the service since the car was bought in germany 21 years ago.