BluSpectre

Hello! I've had my 2011 RX-8 for some months now, and have had my troubles. The coils died on me at 125k, and I tried to replace them with D585s from NP Boosted but that didn't work out, ended up just using OEM coils instead. On my first oil change I started using Castrol GTX Full Synthetic 10w40 oil and premixing Lucas 2-Stroke oil at 200:1 (I know it's light, but the OMP works fine.) and I just got new trans and diff fluids for those changes as well. I am currently just past 128k miles and I was driving along the freeway at about 70 MPH when I noticed I was slowing down. I press the accelerator, and nothing seems to happen. I then release the clutch and the engine drops to 0 RPM. So the engine died on me with no prior symptoms or sounds. I still have 1/4 tank of fuel left, and after having the vehicle towed back I noticed the fuel pump wasn't making it's usual sound when I turn the key to "On". I've checked the fuses and cleaned the connectors, but both of those things seem to be perfectly fine. I've been leaning towards the idea that the fuel pump or the fuel pressure regulator within has either failed or shorted out, but I can't be certain. Any additional suggestions on what to check?

Jedi54

iTrader: (7)

OEM coils - good
full synthetic 10w-40 - no problem.
Pre-mix: good, shouldn't be an issue
Trans / Diff fluid change: wouldn't cause this

honestly it does sort of sound like a bad fuel pump. I had mine randomly last year and you're correct, usually you can hear the pump prime when you first turn the key.
Did you check all your fuses?

BluSpectre

Perhaps some prior information would be a good idea. I've noticed the car smells like it's rich on idle, but the Cat is still intact and looks shinier then the rest of the exhaust, hinting that the previous owner may have replaced it. The car is also often rough on idle, but I can't pinpoint the cause. I replaced the MAF sensor because my OBD 2 tool was reading -40 degree intake temps at 90 F ambient air, so that seemed faulty. After replacing the MAF, the Rough idle was not fixed but the intake temps were. I noticed recently a squeaking noise that inconstantly starts when I start the car, but sometimes it goes away after a short while whereas other times it doesn't go away after 100 miles. The sound seems to become very obvious when I press the clutch in, but quiets down a lot when I let go of the clutch. The combined symptoms made me believe that maybe my throw-out bearing or pulley system may be worn, but the sound is loudest with the clutch fully depressed so the throw-out bearing probably isn't the culprit.
Anyways, those are other smaller issues. The primary issue is the car suddenly dying on the freeway without warning. The car will turn over at the correct speeds, but just won't start. I still need to recheck the ignition ground points and power through the fuel system cables, but I will need to dig up some schematics to check those.

BluSpectre

Yeah, fuses were the first thing I checked. After they were all fine, I re-cranked the car and then I realized the sound wasn't there.

BluSpectre

Sorry for being AWOL for a bit, I went on vacation and forgot my password on my phone...
So I scoured the forums and browsed various auto stores and online webstores, purchased a Deatschwerks 65c 265LpH fuel pump and fuel sock for the RX-8 and installed it successfully. Upon removal of the pump assembly, we noted that there was virtually no fuel left in the tank. Our conclusion was that I believed I still had a quarter tank of fuel, only to run out of fuel and burn out the fuel pump. Installing the pump wasn't hard, and with fire extinguisher in hand we heard the new pump prime and charged the lines before startup. It ran, but very rough and spitting a decent amount of burnt oil and moisture, but didn't smell sweet like coolant (the car was sitting for almost a month and there was heavy rain during this time). The bluish oily smoke went away after about 30 seconds, but the moisture continued to fade out for the next 5 or so minutes. Once there was no more smoke and the car was warmed up, we drove it out to get some gas and preform stress tests in case that were necessary. No issues, no leaks, no stutters or stalls.
Today I drove my car to work, and it started normally this morning. The usual startup, nothing abnormal and no problems. The car still idles rough, and we suspect a vacuum leak near the auxiliary runner. When I got off work earlier, it was about 100 degrees outside and the car started rough in the heat (which seems to be normal, because this seems to always happen) and threw a misfire code once. A simple blip of the gas always seems to make the car behave when this happens. Everything else seems to be fine, and the fueling issues is resolved. I still would like to fix whatever vacuum line is loose or leaking, and the rough start when hot doesn't seem to be just me. But yeah, she's running again and that's nice!