Hey guys I've got a really strange problem:

13B EFI engine with 255,000km on the clock. AFAIK it's never been rebuilt. It sat for 5 years and after about a day and a half I got it running again. It was running just fine for a week and all day today then out of nowhere I shut it off for 10 mins while I tried to figure out why the passenger door won't open (more on this later), and I go to start it again and....nothing. It won't start. Pulled the plugs and dried them off (engine was flooded) pumped the gas out of the housings threw some 20W in the housings and it started up again and idled for about a minute and then died. Wouldn't start up again. Checked the fuel line both before and after the filter and both sprayed fuel. Left it for another 20 minutes or so while I had a smoke in a confused rage then tried to start it again and it started up just fine, but it would start to sputter and die when going below 1k RPM. It also started to make a strange knocking sound.

That's how it sits right now. Why won't it idle anymore? Why does it only start when it feels like it?

I took some videos:

http://www.youtube.com/watch?v=t02Vlz-BnAI
http://www.youtube.com/watch?v=ukGiwChIs8I

You can hear the knocking in the second video. What the hell is that? It sounds like rod knock but this is a rotary so there are no rods. When I pulled the spark plugs from rotor 1 (the one nearest the front of the car) they had some oil on them (trailing had more oil on it than leading). I think there is a seal blown in the engine somewhere.

 

Compression Check? The OMP could be your source of oil, as rotarys use oil that is injected while it's running.

 

Ok, is checking the compression on a rotary the same as checking it on a piston pounder?

Is the OMP issue damaging to the engine? I'm fine with it burning oil (it's going to do that anyways)

 

is there a noticable amount of smoke coming out the exhaust? The knock probably isn't all that engine related as far as I can tell in the video because its more of a rattle like maybe a broken mount or exhaust hanger or something along those lines possibly. Nothing to rattle or knock or chatter in the engine at that low of speed. I guess go ahead and check compression, timing, vacuum leaks, Idle setup (Initial set coupler jumped, Idle, TPS, Air/Fuel screw,initial set coupler un-jumped). Basics.

Compression: not like a piston engine. You'll only get max compression by using an un-modified compression tester. You can take the shraeder valve out of the bottom of the compression tester and then put it in you leading plug hole and have someone crank with the throttle wide open and watch the needle jump to its highest position, then note those numbers

 

It would billow huge white clouds of smoke when we dumped the 20W in to start it but I figure that from the engine burning the oil. I think it would mist smoke otherwise when starting though.

I was reading somewhere that the BAC system could lead to a no idle condition, could that be the case here? The BAC system is all hooked up and hasn't been touched, but something might've busted in it and it's not oscillating properly now.

 

Do you have to use oil every time to start it? That tells me right away that it has low compression. But yes the smoke is coming from the 20W you put in it to start it.

BAC? No. Its an idle "maintainer" more than anything else, such as power steering load, AC load, etc. You could set your idle to 800 and completely unplug the BAC and it should stay right at 800 give or take 50 rpms (if the idle sequence was setup correctly). You can test it by simply listening to it. Turn the key to "on" and don't crank the engine, then go over to the BAC and listen closely for a "humming" sound coming from it. it may even vibrate a little. If it does neither then take a volt meter and check for voltage from its connector with the key on. If there's voltage, then bad BAC. but I personally think the problem lies elsewhere.

 

For the last week I haven't had to add oil to it once. it would crank for 2-3 seconds then start up. But all day today, and all day when we first got it (just over a week ago) we've had to add oil to it to start it.

So how do you fix low compression on a rotary? Replace the apex seals? or the housings? or does the engine just need a complete rebuild?

There is a humming or high pitched electrical whine coming from the engine when the ignition is on. I figured it was a parasitic draw from something but I guess it's just the BAC.

 

to fix low comp, rebuild the motor.

Now if tis an idle issue, then you can fix that too

comp test the motor, pray for 90psi plus

 

I should also mention that if you keep the RPM's above 1k or so it runs just fine. The oil pressure at idle dips just below the hash mark before 4kpa (I'm guessing that's 2kpa) but pressure builds with with rpms like it should.

I know very little about rotary engines, but it makes sense that compression would rise with engine rpm. Is this thinking sound?