Ever since I got my car running at the end of June It seems to put fuel into the oil pretty fast. I can change it and drive it 50 miles and be right back to a dipstick that smells like gas. After ~300 miles I can actually start to see the oil level rise a tad, maybe 1/8". I know it's rich in areas but even if it's very rich will this much fuel seep past the seals into the oil?



It's a 13B-RE with no PCV setup, the vents just go to free air. I know that isn't helping the situation but still seems like a lot of fuel https://www.nopistons.com/forums/pub...1047683561.gif

the fd's do this too, i think its just being rich. you not having any sort of vacuum on the crank case prolly isnt helping.



actually mine kinda does the same thing, i havent really looked into it too much yet



mike

Think if I hook direct vacuum to one of the ports on the filler neck it would be ok?



If I remember right there is a vacuum port right at or near the primary injectors, would this be a good place to run the line to the filler neck? That's if it's ok to run dirrect vacuum...

the factory usually puts it before the turbo. i think you just have to make sure it doesnt see boost



mike

Check to make sure your ECU is cutting fuel on decel! I fucked up one motor (spun bearings) and thought I was just running to rich. I dialed in the fuel and was still getting fuel in my oil. One day I was watching my inj duty on decel and it was staying the same after I got off the gas. I also was making nice flame shows on decel. After I fixed the problem(inj duty goes to 0% on decel) I no longer get fuel in my oil(not anymore than the normal rotary).

If your ECU does not have decel settings, you can set the fuel map up to give no fuel in the decel vaccuum areas. On my car I never see -550 vaccuum while driving. I only see these values when my car goes into decel, so what I did was set the whole -600 row to zero. It's not perfect , but it works. I run a power fc, which does have decel settings, but I was having problems with it, and did this as a temp fix(1 and a half years).

Intresting, I thought rotaries didn't recover well from fuel cut on decel? In the 22-30ingh areas I have it set to ~1.8-2ms, would that be too much fuel? (550cc primary inj)

They don't. I've run into this issue many times.



I think more of the compromise that ought to be met here is keeping a stoich to lean mixture in the motor on decel (30 to ~15" vacuum) to help prevent the problem that IGY ran into (although I'm still not sure if that's all that was entirely the problem nor have I ever heard of that happening before).



B

yeah if you do do fuel cut it needs to turn back on at something like 1700-2000rpms



also if its too lean on decel it will want to buck



mike

yeah if you do do fuel cut it needs to turn back on at something like 1700-2000rpms



also if its too lean on decel it will want to buck



mike [/quote]

Yep. Same issue I've run into several times, Mike. That's why I don't use it.



B

I think the PFC does it by default. I always got 0ms under heavy decelleration.



This is likely why it would buck slightly coming down a hill with cruise control on, based on your descriptions.

Wait a minute... just thought of something.. on heavy decel (27-23inhg) woulden't it want to pull oil in the combustion chamber instead of putting fuel into the oil??

You'd think so at first blush, but it depends on the two competing forces -> pressure in the oil system through the crankshaft vs. combustion chamber pressure.



B

Well in this case both forces would be working together to reach the same goal, pull/push oil into the combustion chamber.

i think it can wash down the housing walls like a piston engine, i have nothing to base this on but hey it sounds neat huh?



mike

Yes the power fc does this automatically, but mine was fucked up. Yes you can minimize the problem by creating a lean condition in the decel vaccuum areas. Yes, it takes a long time to get the accel enrichments correct, to recover from zero fuel on decel, and yes fuel does have to be added from 1500-2000rpm's to eliminate idle surge, but it can be done. The power fc does this as a default, but everything changes drastically with different inj sizes and fuel pressures.

How many miles were on your fuel enriched oil when the bearings let go? I think I've changed my oil 4-5 times in the 2600 miles I've put on my setup.

ok i actually went at looked at mine (20b) and theres 2 parts to it.



the fuel vapor line comes from the tank to the charcoal cannister, and then goes to the vacuum rack (cosmo is multi peice, so i'm only using the pcv and metal fuel lines) where it goes to the oil filler neck. teed into that pipe is a hose that goes to the tid, with a check valve. the vapor/fuel/oil can only go into the tid. this is have hooked up like it came, ie its stock like this.



the second part, the nipple on the center housing right below the loi filler neck goes to a pipe which went to the purge valve (the round one) and then into the bottom of the tbody. this part i had blocked off, i just went and unplugged it so now it sees atmosphere, should it see vacuum?



mike

hmm.. I can't remember what any of that **** looks like since I took it all off over 1.5 years ago :(

lol, i know, the only reason i remember is cause i put half of it back



mike