jas0n

I have a 2004 RX8 automatic with 78k miles. The car sat for about a year or a year and a half. Everything looks good on the car so I bought it knowing that the engine is not turning over. Got the car towed home and got it running after deflooding the engine for about an hour. Got a new battery since the old one was from 2012 and I blew it by overcharging it at work lol.

I can get the car to start up. Every time the engine is warmed up or when the coolant gauge reaches near the middle, the car dies when I place it in reverse or drive. It is fine in Park, but that's when I'm not switching from Drive or Reverse to Park. Not sure about Neutral. If I don't let the car warm up and place it in Reverse or Drive, it is fine. I can even leave it in Drive until the car warms up and it will still not die, unless I switch it out of Drive. Scanned for DTC and could not find any codes.

Is this a fuel pump issue? Torque converter? I don't want to pull the engine out yet unless I know it's time to rebuild it, which I should anyways since it's high miles.


I have not changed the spark plugs, coils, or spark plug wires. Also did not change or add new gas, coolant and engine oil yet. However, I did remove the coils and checked beneath for white spots which I did not see on any of them. Also pulled out the spark plugs and cleaned them. Was going to replace them, but they are like $20 each. Transmission fluid looks good; checked it when the car is hot.

Just trying to see if anyone have dealt with this issue before I put more money into the car.

Here's a video I recorded:

9krpmrx8

iTrader: (46)

It could be many things, it is likely a vacuum leak but it could be a serious as low compression. The issue needs to be properly diagnosed.

Start by following the troubleshooting here under "engine symptom troubleshooting":

http://foxed.ca/rx7manual/2003mazdar..._S01_0016.html

RX8Soldier

iTrader: (24)

^+1
And read the stickies (particularly the new members). Plenty of relevant info that will get you up to par on these engines.

wannawankel

Torque converter might be fried - did you perhaps have it towed with the rear wheels down on the ground - even for a short distance - with the rear driveshaft in place and not disconnected?

jas0n

I don't know if previous owner had it towed before, but I do know the car was at Mazda dealership a few times in the past. I had it towed with the rear up. Tow truck driver literally almost towed it with the front up until I stopped him.

NotAPreppie

Does it die if you shift into gear before it's warmed up?

wannawankel

Idiots - however rear wheel drive cars are rare and they are not "qualified" or required to check this to tow.

Ed

jas0n

It only dies when the car is warmed up and i place it in gear. If the car is warmed up and idling in park, does not die. When it idles in park and warmed up, i can rev up to redline with no issues. Havent gotten a chance to mess with the car since starting this topic. Been busy with work.

Nisaja

I thought you said a vacuum leak would increase the idle rpm

9krpmrx8

iTrader: (46)

You thought?

Nisaja

Haha looks like you replied to this exactly one year ago

jas0n

I'll be working on the car tomorrow. Do you guys think I am in need of new coils and spark plugs? I am going to assume the previous owner did not change them out. When I took off the coils before, I did not see any white burn marks underneath. I took out the spark plugs to clean them and found the top and tip of the plugs are black.

Once I replace these (which seems to be a requirement with the rx8), hopefully my problem would be solved. If not, at least I know I'll need a rebuild and I'll have new plugs and coils ready for the rebuilt engine.

mazdaverx7

iTrader: (6)

Before you go any further let me ask this. After the engine stalls and you place the transmission back in park, will the engine restart? If not then I would suspect low compression ad perform a compression test instantly if not sooner if you already have not done so.

If it will start right back up, I would suspect the torque converter to be faulty but would not condemn it without proper diagnosis in other areas.

Do you ave any DTC's or pending DTC's?

jas0n

Tough to start when the engine is warmed up, but I can get it to start if I hook up a battery booster after several tries. Should I try changing the engine oil and filter first? I can see that it leaks oil on the ground whenever I start the car up. Maybe it's over filled at the pan and oil may be seeping through the RTV. Also the gas in the car has been in the tank ever since it sat for over a year ago.

No DTC or pending DTC when I scanned for codes.

Have not bought the plugs or coils yet. Pretty sure it's low compression, but just wanted to see if there's still hope.

mazdaverx7

iTrader: (6)

The oil pan doesn't hold much oil. An oil and filter change is only 3.7 quarts. Chances are its not seeping oil from the oil pan seal. I would look more into the oil cooler lines leaking if they're rusty. Where is the leak on the ground in relation to the engine? Check the oil to see where the level is at. Changing the oil won't help starting issues but if compression turns out to be decent, you will want to change the oil sooner rather than later.

Difficult to start when warm can be low compression so make sure you run a compression test. Weak ignition components plague these cars, so its best to have a strong battery and good ignition components. Weak ignition components can cause flooding and difficulty starting. So, not a bad idea to replace the plugs, wires, and coils.

jas0n

Thanks for the info.

So today I replaced the coils, spark plugs, and wire set. Also did an oil change. Started the car up, let it warmed up, rev and held the rpm at around 2500 for 20 seconds and then did the same around 4800 rpm. Let it idle for 30 minutes. I placed it in Reverse while holding the brake pedal, ebrake up, and pushing the accelerator pedal to around 1200 rpm so the car won't die. I then slowly let the accelerator pedal off until around 800 rpm. I can hear some noise rattling/moving around, but cannot find the culprit since I was by myself. I then rev it up and held around 1200 rpm and the noise went away. I needed a second person to look or hold the pedal while I look.

I did the same thing in Drive and heard the same noises. I slowly let the accelerator pedal off until around 800 rpm. I slowly removed my right foot out of the way and the car stayed running on its own while holding the brakes and having ebrake up. Again, when I rev it up and hold it around 1500 rpm, noise goes away. Tried to make it stay running in Reverse, but couldn't replicate how I had it in Drive and it died just like in my video.

I'm gonna wait until I can get another person to come help me so I can determine if it's the torque converter or not.

mazdaverx7

iTrader: (6)

Did the tune up and oil change help the issues you were having at all?

Jack the car up and check to see if any of the exhaust heat shields are loose. Be sure to check the heat shield around the exhaust manifold as they commonly break loose. If you can find no loose heat shields, I would start looking at the catalytic converter as the culprit. They will break apart and cause a rattle. Remove the converter and shake it and see if anything is loose in there. You can also tap on it and if its broken apart you can hear it rattle as well.

jas0n

Today I was trying to removed the catalytic converter, but one of the nut on the front flange started stripping despite letting it soak with PB. So I started putting everything back together except for the 2 nuts on the front flange that I took off.

Started the car and warmed it up. Of course there was smoke coming out the flange area due to the exhaust leak now. I was trying to record a video of the noise under the car from my previous post, only to find that my car stays running in Reverse and Drive now. My guess is the catalytic converter since the air is coming out the exhaust leak and partially going through the cat. DTC came up for the exhaust leak.

Does it sound like the cat is the problem to you guys?

jas0n

Update: Just started and warmed up the car. At first I was able to get it to stay on in Reverse and Drive by reving the engine while putting into gear and slowly letting go the accelerator pedal.

Decided to back up my daily out of the way so I can drive the 8 around the block. As I place it into Reverse without reving the engine at the same time, the car slowly died with the RPM sweeping to 0 from around 800 rpm. While it was doing that, I heard a hissing sound until the car died. Sounds like a vacuum leak, but it was loud enough for me to hear it while inside the car with window down. Anyone experience this or know what it might be? Where should I start when wanting to find a vacuum leak?

Again the car stays on in Park and Neutral with no issue. There is vibration around 900 rpm - 1k rpm when I rev the engine and it goes away until it hits around 900 rpm - 1k rpm. At idle, there is no vibration.

Rafa Gonzales

Im having the same issue with my 2009 RX-8, did you get to fix yours? Im thinking mine has an issue with the fuel pump..

UnknownJinX

Don't guess, properly diagnose.

S2 fuel pump is improved over the S1 unit. I haven't seen reports of them failing here.

Start with the easy and obvious. Transmission fluid colour is good? Level? Any vacuum leak? Cracks in the intake system?