924Board.org

[illmatic]

Hello!
I have been reading this forum for some time now, so now decided to join with my 924 journey.
A year ago I stumbled upon a 924 for sale and something caught my attention. I checked it out and it was in very poor condition, so I decided to pass on it. Since then I kept thinking about this model. I started to read up on the history of this car, the designer Anatol Lapen was of Latvian descent. Couple monts later there was one more 924 for sale. The owner had really put his heart and soul in it. It was looking and functioning properly. It was a great deal. It is stock 1982. 2.0 na European version engine with 89k km on the clock (the odometer is not working anymore but it is on the to do list). As I was told, the engine had an overhaul done, the head resurfaced, piston sleeves replaced. Only modifications done by the previous owner I know about is the fuel filter is set on manual switch, the cold start valve is also set on manual switch. For the first summer I owned it It was running decently, aside from running a little rich, and heavy exhaust fumes coming in the cabin. First thing I did was I changed the exhaust gasket between the exhaust manifold and exhaust pipe, and also changed the sealing ring for the muffler. This solved the exhaust fume un cabin problem.
Once the winter came I had some problems starting the car, changed battery, distributor cap and rotor, new spark plug wires, after changing the spark plugs (the old ones were really black from running rich for a long time) the car started ok. I took off the WUR opened it up and it had some goo in it, took it apart and flushed it with carb cleaner, the inlet mesh seemed clogged but after a lot of flushing with carb cleaner it got better. Measured the resistance for the bimetal part, to make sure it functions properly. Did the repair kit with all new gaskets and screws from partworks.







After reinstalling the WUR the cold start process worked as it should (?) when it was cold (around -5 celsius) the car started and idled high around 2000 rpm for 5-10 minutes and then slowly the idling revs dropped to 900ish when the engine warmed up.
Once the engine got warm and the thermostat fan turned on and off for one cycle. The idling got very chaotic the revs dropping to almost stalling. When I pressed the brake pedal the revs went up to 2000 rmp so I started to hunt for the vacuum leaks, which brings me to the question. What parts should be checked and be culprits for vacuum leaks?
I checked the tubes from intake manifold to intake boot and venturi tube to brake booster check valve.

These pipes didn't show any leaks. The pipe from Auxiliary air valve on the other hand had some bad cracks in the inside corners and around the clamps.

I did some temporary fix by sealing the whole length of the pipe with a tape. Would like to find some aftermarket formed vacuum pipes with right dimensions, as the original ones are not easy to find, and if there are some used ones available then quality is poor considering the age of them.
Regarding the vacuum leaks, does the oil filler cap and the dipsitck top part contributes to the vacuum system? I ordered new oil filler cap as the old ones gasket is not sealing properly. The dipsticks seal is in terrible condition.

Missing most of the rubber part. Does anyone know any other cars(VW, Audi) that could have same rubber part of the dipstick, I understand that the dipstick itself might be different length for different engines? Once the AAV tube was sealed and dipstick tube was plugged, the vacuum system worked much better, the idling was more stable and no increase in RPMs when brake pedal was pressed.
I would really like to get the vacuum system properly fixed before adjusting the idle adjustment screw on the throttle body.
I will keep updating this topic.
_________________
1982 924 2.0 n/a

[Raize]

I don't think the crankcase should be connected to the vacuum system on any Euro cars but may be wrong. Check the crankcase breather hose at the back of the block below the brake booster - if it goes to the bottom of the airbox then it doesn't effect anything. If it goes into the middle plastic pipe between the air flow meter and the intake manifold then it will effect your vacuum system.

Normally when the brake pedal is pressed on mine the revs drop because you are getting some unmetered air through the booster which leans the engine out. If the revs are rising then it might mean you are running extremely rich.

The dipstick seal just slides off so if anyone in Europe had a spare one it probably wouldn't be hard to post. I have one my self but lol BREXIT.