KA24DE Oil Burn Diagnosis

[StuckeyOG]

Okay so I have a S14 with a stock KA. It's been burning oil (I just did a 500 mile trip and it burned about half a quart) and throwing an idle code (can't remember which) since I got it. It tends to idle high on startup for a while and the rpm's will drop to like 400 or so on take off sometimes before it catches.

Nothing too bad but I'd rather nip any problems in the bud. I recently added a HKS Sport catback and the first few days there was an awful smell but I read that was normal. It's been a couple weeks and I've more than broken in my exhaust, the smell has been gone.

However, I was leaving my transmission class the other day and my friends told me my exhaust smelled like oil a lot I hadn't noticed yet. I revved it up with the windows down after it had rained and I could definitely smell burnt oil.

It was a bit cooler yesterday morning and when I revved it and had my Dad look there was a bit of white smoke from my exhaust. Not a bunch but it definitely wasn't the usual hot exhaust on a cold morning type of steam. I have a few theories:

-Worn valve seals (the most likely)
-Worn rings or ringlands (probable)
-Stuck or Leaking injector (unlikely, I'm still getting around 20mpg combined usually)

Anyone had a similar problem that can provide input? Thanks

[Wykydtron]

Sounds similar to what my s14 KA is doing... interested in hearing what others say...

[nd240sx3]

i would say worn valve seals.. check ur compression.. if all the cylinders are a good psi and all around the same ## usually means worn valve seals... i actually just did a head gasket on my vehicle and took a spare head with new valve seals to a machine shop to be decked and seals installed... no more burning oil! wasn't to bad cost wise either seals thru nissan are dirt cheap.. i actually bought 32 instead of 16 so i can install the others in the old head..

[bmaddock]

All of those theories can be easily tested for. I would first try a compression check as previously stated. You are looking for 150psi+ on all four cylinders. Make sure you pull the fuel pump fuse, all spark plugs, and keep the throttle wide open on a warm engine. All four should be within 15 psi of each other. If one is off that is your suspect cylinder.

A simple wet vs dry compression test can tell you a lot. From a quick google search:- Normal: Compression builds up quickly and evenly to the specified compression for each cylinder.
- Piston Rings Leaking: Compression is low on the first stroke. Compression builds up with the following strokes but does not reach normal. Compression improves considerably when you add oil (1 tbsp).
- Valves Leaking: Compression is low on the first stroke. Compression usually does not build up on the following strokes. Compression does not improve much when you add oil (1 tbsp).
- If two adjacent cylinders have lower than normal compression and injecting oil into the cylinders does not increase the compression, the cause may be the head gasket leaking between the cylinders.


Also I doubt it would be injectors but you can check those easily as well. Grab a multimeter and measure resistance of the injectors. They should all be around ~10ohms. If an injector is bad or going out it will be far off from the others (10,000ohms)

[jza80king]

When you left your class did you happen to see what color the smoke was? Also when you said you revved your car and your dad looked you said you got the white smoke, did it eventually go away or did it continue burning white? If the white smoke never goes away well this might be indicative of water/coolant burning which I don't wanna scare you but that means the head gasket might not be sealing correctly. If the smoke just happens upon start up and goes away, it could be valve seals that are worn, I would def do a compression test to see what you get for compression and you will know if rings are shot or not pretty easily. Also, when I was diagnosing my KA24DE issue with smoke I did a cylinder leak down test. This helps diagnosing if you have any valve leaks (intake/exhaust) if any valve is stuck or bent or just not sealing correctly. After doing my test I was able to determine my exhaust guides were bad after I tore the motor apart. Hopefully your valves aren't bad cuz they are expensive.