85rotarypower

Looks like its going to be a little while till I get a chance to troubleshoot anything else. The f***ing fuel pump I just bought is fried. I checked that there was power to the pump, and there is. Its not excessive either, so I don't know whats going on. This is the second pump thats went on the car, and its getting real annoying.

85rotarypower

Ok, finally got a fuel pump. Had trouble starting the car since its so cold right now and my battery isn't to great anymore. But its not looking good. I took the intake manifold off and removed all unnessesary vacuum lines. Deffinately not a vacuum leak. Got the car started, and the condition didn't change. Step two, drive car around the block. It drives nice above 2000 rpm, and plenty of power. Step three, try unplugging things. This is what lead to the car stalling and no restart. I unplugged the MAF, car almost stalled. I tried unplugging the secondary injectors, nothing happened. I unplugged the thing on the drivers side of the UIM, car almost stalled. I unplugged the hose from this thing where it connects to the intake plenum from the filter, engine died intantly. But none of these things explains why it only idles on one rotor. When your on the gas, its fine. But at idle, it surges and only runs on one rotor. I'm starting to thing mabey its a problem with the ECU. There is no strong smells out the tailpipe, so it can't be the injectors leaking. All plugs are firing, and there is no detectable misfire. This makes no sence at all.

Aaron Cake

iTrader: (1)

Unplugging the AFM will kill the car. That's normal.

Unplugging the secondaries should have no effect if the engine is not above 3800 RPM and under load, so that's normal as well.

Drivers side upper intake...air thermo sensor? Unplugging that should cause issues.

Thing to the intake plenum from the air tube...That sounds like the BAC valve line. Unplugging that should stall the car because you'll suddenly be pulling in tonnes of unmetered air.

Have you tried swapping the primary injectors with the secondaries? Just to eliminate any possibility of a bad injector.

What about your ACV valve? If it has failed (in a truly odd failure mode) it will be pumping excess air into the rear rotor...But I doubt that's the cause.

That's all I can give you at the moment...

HAILERS

You really, really, really, really, REALLY, NEED to download the factory service manual from the web and read the FUEL SECTION. Just the FUEL SECTION. It has graphics.

Pull your inlet duct off the throttle body and look at the primary and secondary throttle plates to see if they are cracked open. You have to do this when the engine is hot. They should not be cracked open at all.

gxlbiscuit

From what you described it sounds like you have a bad engine.. a failed coolant seal in the rear rotor. the water leaks into the rear housing when you turn off the car... then you start the car it runs on just the front rotor until all the water is pumped out of the rear rotor then it starts... leads to a rocky idle.. and when you turn the car off after being warm.. its even harder to start cuz the hot water is now pressurized and putting more water in.. do your rear spark plugs appear oily when the car wont start? if they do look oil its not oil its just water and soot. the black on your spark plugs could be carbon and misc from the evaporated water. next time you start the car open the resivior for the coolant if you ahve one and see if it bubbles. you said coolant was refusing to go in the engine... does it shoot out like a super soaker even when the car is cold? if so that a dead engine for sure .. rebuild and port time.. i hope im wrong but it sounds like bad news. if a coolant passage/seal has failed it doesnt produce a gas smell and you barely notice the steam yo uhave to be back behind the car to see it cuz its a small amount.

gxlbiscuit

your rev issue could be this .. i thought about it for a while.. ok when you go above 2000 the rear rotor resumes operation because there is enough compression to blow the water out. the up and down idle could be caused by the same reason the rear rotor gets rid of the water the idle goes up.. then it slowly creeps back in lowering the idle... its good rotor versus bad rotor. or you may have the idle set high (1700+) and it cant get that high but you can hear the engine trying(ocsillating up and down) cuz it will get rid of the water then it will come back in slowing it down again.

85rotarypower

Well, thanks for the input. I replaced the thermostat and coolant started going through the engine. But from what gxlbiscuit said, it doesn't look good. Everytime I pulled the rear plugs, they seemed to be more wet than the front plugs. Coolant isn't pouring out of the rad anymore (was before thermostat replacement), but the coolant level did seem to go down as the engine warmed up. I thought this was just because the thermostat started to open, but now I'm not sure. I really, really hope that this engine is not bad, since I have NO money for another engine or to rebuild this one.

Edit: Checked coolant level again. Perfectly fine. I let the car run for a good 10 min after topping it up the first time I checked it. Looks like I'm taking the UIM off again and swaping the primary and secondary injectors.

gxlbiscuit

ok cool keep me posted.. it could be as simple as a stuck injector ... uh ooh your signature says rebuilt injectors... like said keep me posted.. pm me actually

85rotarypower

Actually, I think the injectors were very cheapily rebuilt. The last owner of the engine said that it had some flooding problems related to leaky injectors. Pretty common I think. Actually, when I got the parts car home that the engine came in, it started right up when on the trailer, but I had to shut it down. After that, it flooded and I couldn't get it to start up again untill the next day. I think I might eventually get larger injectors for it anyway, so no biggie if they do leak a little. But my problem might be a serious leak on one of the primaries. We shall see.

85rotarypower

Ok, I changed the injectors around but no change in the way the car runs. BUT, I did manage to find my timing light so I checked the timing. Well, I found out why its only running on one rotor. It turns out that the rear leading plug has no spark at all, the front leading plug has a VERY, VERY bad misfire, the front trailing plug has no spark, and the rear trailing plug has perfect spark. What could cause this??? Bad coils? I kinda think its a ECU problem, but I don't know enough of how the ignition system works on the FI cars to know whats wrong.

Aaron Cake

iTrader: (1)

Both leading plugs fire off the same coil, so if one fires, so must the other. Timing lights are not a reliable way to check for spark as the rotary often misfires them. If you want to check for spark, you need a spark tester. It's basically a spark plug with an alligator clip that you connect to a ground.

That said, at this point, you might as well try swapping on a known good leading coil/ignitor assembly. How are the plug wires?

gxlbiscuit

yeah just grab some extra coils(should be cheap and easy to come by.. do a compression test for ***** and giggles too. i havent wired up a s4 fo Sa before .. but thats sounds pretty muffed up(captain obvious) i cant help you much there because i dont know how you have the wiring and stuff set up. well later

85rotarypower

Well, I've got another coil here, so I'll try that.

BTW, I've used this timing light on my last engine, and it seems to work perfectly fine.

Aaron Cake

iTrader: (1)

Some engines/lights are better then others.

I have a light that works great on everyone else's car but mine. Go figure.

85rotarypower

Well, we will see. I've got another coil with a bad ignitor here, so I'll swap that on. I'll also get some new wires, even though mine test out fine. I know for a fact the plugs are good though since my old engine ran PERFECT on these plugs. It never once misfired.

85rotarypower

Well, this project is being put on hold for at least 2 1/2 years. Turns out the compression is low. 60psi on the front and less than 50 on the rear. When I tested my 12A cranking at the same speed, I regestered over 100psi on both with this same tester. I don't have the money nor the time to swap this engine out for another, so I'll just rebuild it as I can.

Its been fun though, and the time i did have driving the car I had a blast. I will be back though.