xodaraP

Hi all,
Did a search but couldn't find anything on this, it is definitely strange. Today I dropped my oil, changed the oil and changed the filter, first time I've done it since I've owned the car. I have posted before about the insane fuel usage on my car, and today I can see that a lot of it seems to be getting into my oil. It was so watered down it's probably close to the point of dangerous. Something is just dumping fuel into my engine and I need to figure out what.

I have replaced the oil, filter, sparks, couple of belts that needed replacing, checked everything with a multimeter and all seems good, the car runs really well, though it does have a very high idle (1500RPM) and often jumps around between 1200 and 1500RPM at idle. Air filter was also replaced 2 weeks ago.

Next step is replacing the O2 sensor, I have one here to replace it with, but any further ideas would be appreciated, I do know that a bad O2 sensor leads to bad mileage, but the fuel in the oil definitely seems like a lot more than even a bad O2 sensor can cause. Also going to try and redo the grounds on the ECU, hoping that might help.

Any other ideas appreciated. 150km/tank is driving me nuts on a bone stock engine.

Edit: The spark plugs removed from the car did not seem too bad at all, they were definitely not coated in fuel and oil and generally looked pretty good - I almost didn't bother replacing them when I pulled them, but figured since I ordered in the new NGK plugs I may as well do it while I was there.

Blaen99

iTrader: (1)

You should probably search for oil seal failure and/or similar words.

From what I've read on here, the main cause of fuel in oil like that is a failure of the oil seals.

jake1191

iTrader: (1)

The main cause of oil in the gas is the car is running rich or has been flooded. After that is the possibility of a side seal or other seal. Premix will also cause gassy oil

xodaraP

Thanks Blaen99, will search up for oil seal failure

jfpimp91elkland: My car is running extremely rich, there is no question about it. I am using massive amounts of fuel, the exhaust absolutely stinks like it's running rich and now there's fuel in the oil

Would I have lost oil seals after such a low number of k's though? Still seems odd that I'd have that much fuel in the oil if it's oil seal failure, but I shall search it up.

Thanks,
Sean

xodaraP

Hmm. Judging from what I've read about oil seal failure I don't think it's that due to the fact there is no oil leaking from the engine at all. And there would be in the case of oil seal failure. I believe the fuel in the oil is being caused by how rich the engine is running. Need to figure this out.


Next step: O2 sensor and ECU reground. Any other thoughts appreciated.

vrracing

iTrader: (1)

I would bet that your injectors are dirty and after you shut down they are leaking the fuel in the system (remember it is pressurized) into the housings and into your oil. You can get your injectors cleaned at KGparts.com or witchhunter.com; maybe even locally.

Leaking injectors will also cause a very bad rich condition since they wont fully close and will be spraying fuel all the time.

All of which matches your symptoms.

Good luck

xodaraP

Thank you very much vrracing I will pull them out and get them cleaned - I believe we can get it done locally. It is a DD for me though so I can't have them gone for long periods but I have some holidays coming up, so I will pull them off and get them cleaned while I'm away anyway and don't need the car as a daily.

Didn't think that would explain the wierd idle and that, but I'll replace the O2 sensor anyway, and get the injectors pulled and cleaned. Might get a new set while I'm at it.

Thanks

vrracing

iTrader: (1)

The O2 sensor only comes into play when you're at a pretty steady RPM under light load. Like when you're crusing along. It doesnt do anything at idle.

The weird idle could be caused by the stuck injectors because they cause it to run rich, the ECU compensates with the BAC and lets more air in and it ends up chasing the idle. The ECU wants to run a specific idle and will chase it. The other probable cause of the idle problems are your TPS and if you have vacuum leaks. Both are common and you should be able to find lots of posts and articles on addressing both.

eage8

iTrader: (9)

I'm currently having the same problem

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/gas-oil-%3D-821515/

it might not be as bad as I originally thought, (I've discovered the dipstick is completely useless when anywhere above the full line)

I would send your oil away to be analyzed to see how much is actually getting in it.

yours is probably just running really rich, the engine is probably fine. I would deffinitly get your injectors cleaned though.

xodaraP

Thanks guys,
I know for a fact it's definitely running rich, and when the idle starts to drop, the car suddenly surges back up to 1500 - I was thinking this might be the ECU telling it to do as such. Strangely though it sometimes sits dead on 1500 without a problem then it'll suddenly change and start jumping all over the shop again.

Going to pull the injectors and have them cleaned - vrracing seems to have the best idea of what's happening (ie. my engines not blown) so I'll try that first.

Compression is good on both rotors as well and should be considering the low mileage on it (100-105psi all facings, both rotors). So I don't think it's a seal blown. I have checked the TPS and it is dead on after an adjustment, and I have checked for vacuum leaks but so far haven't found any. I am going to start replacing vacuum line though as the previous owner has used an awful lot of tape to block off holes created by a previous installation of a boost gauge.

Thanks,
Sean