titaneum_grey

04, 8. 116 thousand miles on the engine. No problem starting it cold. No CEL's. I bring the rpms up fast, in 4,5 & 6 gears, and the engine breaks up. Bring them up slowly and it's fine. Feels like I'm not getting the power out of it that I use to. After running on the highway it stalls if I take my foot off the gas and disengage the clutch, like when hitting traffic. Been stalling a lot at slower conditions lately as well, like at stop lights. And it doesn't want to restart after when it's warm. Sill, no CEL's
Recently:
Cleaned MAF and fuel injectors.
New coils wires and plugs.
New air filter.
I took it to the Dealership and paid for a diagnostic.
Came back No Problems found.

Any ideas where I go from here?

fish1

Maybe look at replacing the fuel pump.

Loki

iTrader: (1)

Low compression. What did the dealer diagnose and did they perform a compression test?

titaneum_grey

Thank you.

I thought about the fuel pump, as well as an exhaust obstruction but then the question of why it only happens in 4, 5 & 6th gears and not in 1st, 2nd & 3rd. If it were the fuel pump wouldn't it happen no matter what gear I am in?


Not happy with the dealership work. They used the word thorough but didn't give me details. I was in for something mechanical at the time and regret not pressing the issue.
When I bought my first 8 they told me the rotary engine was good for 300,000 miles. But lately I have been thinking along the same lines and researching apex seal information.
Would I get a CEL with low compression?
I can do a compression test myself but will need to find a good shop here on long island, as I don't have the shop space to do my own seals.


Regards.
Angelo

Loki

iTrader: (1)

You need a special compression tester for a rotary, so it's either Mazda or a rotary performance shop.
Low compression won't give a CEL, but it usually manifests as not being able to restart the car when warm. Related and possibly causing the high-rpm breakup, is a clogged catalytic converter.

I don't think anyone can promise that any engine lasts to 300,000mi, never mind a rotary So that was a flat out lie.

If it is low compression, your best bet is to buy a freshly rebuilt engine from a reputable rebuilder like RotaryResurrection. When you open a failing rotary, often big parts are worn out of spec and shouldn't be reused, at which point you either gamble and leave them in, or go shopping for new housings. With a rebuild, you know you're getting an engine that's in spec.

Chrishoky

iTrader: (9)

Wow....

titaneum_grey

Yup, just learned the compression testers I have will not work.
Wouldn't a clogged cat generate a CEL or code?
And, if it is the cat or other form of exhaust clog, wouldn't I get the same symptoms in all gears and not just the top three?
Thanks for the heads up on a fresh rebuild over just doing the seals.

Regards.
Angelo

BigCajun

iTrader: (1)

Yeah, a P0420 usually pops up, but Idk if it always does.

Mine ran fine with a bad cat for a while, but as it got worse it started to misfire and lose power at higher gears and revs.
If you don't need it to pass inspection, try a midpipe.
You get better MPG, performance, sound, and peace of mind.

I get the code now because I have no cat, but it's weird.
Sometimes I can go weeks without it, sometimes it's every few days.
*edit* You can try cleaning the ESS and do the 20 brake stomp, that might help, especially if it hasn't been cleaned with all those miles on it.

titaneum_grey

To determine if the problem was in the exhaust or not I removed the O2 sensor on the cat and went for a parkway run. Power was slightly better, throughty sound at high rpms was gone, breaking up in higher gears at high rpm's was almost non-existent but I could still notice some slight sputtering. I got the code for the missing sensor but the odd thing was my DSC off light was on instead of the CEL.
After getting off the parkway it didn't stall right away but it did stall once. It was also much harder to restart then it had been with the sensor in. But the tendency to stall was much less. in fact it only stalled the one time and I drove through town before heading in.
I don't know how much damage to the seals running it like this has done, if any. I will go with a new exhaust from the header back and have a compression test done after the install.

titaneum_grey

Hey Big.
I hope you are well.
I do need a cat to pass inspection or I would go with a midpipe.

titaneum_grey

I got my new cat today and pulled out the old one. I don't see much difference between them. The old one has a crack running through the mesh bit the mesh itself doesn't look clogged compared to the new one. Have attached a pic of the old and the new.
Is it possible that my muffler could be the problem and not the cat?
A while back the stem for my muffler rotted and I had to braze a new one on. I attached a pic of that too.

ZiG

Keep in mind they can clog from the back forward, and as I learned from some recent drama on here, a crack is a very bad sign indeed.

BigCajun

iTrader: (1)

Did you try shining a light through it?
If it's clogged you won't see any light.

TomD_Cincy

iTrader: (2)

On my previous 8, my cat melted down when I had an ignition coil fail. The front of the cat looked fine. But when I pulled the O2 sensor I could see the backside of the front element was severely distressed. I would bust the element out of your old cat and run with that and keep your new one to install when you get your emissions tested.

titaneum_grey

Thanks everyone.
I didn't shine a lite through it since the pipe bends but I could try going through the O2 port.
I looked at the mesh aft of the sensor and it looked fine too but I also noticed a greasy coating aft of the resonator so with this in mind and what I have read about the crack, I feel better about just installing the magna-flow and seeing how it runs after that.
If it doesn't run right I'll pick up a cat back exhaust.

titaneum_grey

I don't think the problem was my cat. I just had to know so I chopped out a section both before and after the O2 sensor. As you can see from the pics, Clean as a whistle, not a speck of clogging to be found.
This has been an expensive lesson. When the car ran better after taking the O2 sensor out of the cat I should have tested further down the line and disconnected the muffler with the sensor put back in.
Not only did I not need to purchase a cat but magna-flow only sent me one of two gaskets needed to compete the install and only two nuts for the five bolts that came with it. Adding another $50 in hardware to get the job done.

Loki

iTrader: (1)

Wait what? You demolished the cat to confirm its health? Or was it already in pieces?

Legot

iTrader: (1)

Just from reading this I'm pretty certain that the actual problem is your fuel pump. It's a common point of failure, and a failing fuel pump would cause issues when the engine is under different loads.

When all else fails, the solution is never to destroy the single most expensive component in your car.

BigCajun

iTrader: (1)

Yeah, well, the light would have illuminated the inside of the cat even with the bends in the pipe.
That's why I suggested it.

Lead a horse to water....

titaneum_grey

I did shine a light in the *** end of the cat before cutting into it and No it didn't shine through, even with the bends.

Funny how the people who thought it was the cat are now silent or changing their tune..... and that horse to water crack, that's messed up Big.

BigCajun

iTrader: (1)

Ok, it was unclear. I thought you didn't shine a light because of the bends.
If you didn't see the light, unless it was a dim light, then it probably was clogged.

The crack?
Well, I am kinda messed up.

BigCajun

iTrader: (1)

I retract my last statement.

titaneum_grey

Up till earlier today, when I was discussing it with a racing mechanic, I didn't understand how I could get fuel issues in only in the top three gears.
I did ask about it earlier in this post but got no response. So I went in another direction.

I thought I had it figured out and didn't even think I wouldn't find a clog. I really just wanted to see what it would look like. Looking back now I can think of five things I could have done differently, but didn't.

Never been one for screwing up on the small side.

titaneum_grey

No, you were correct. in my earlier response I stated why I didn't. It was after you pointed it out I reconsidered and tried it before cutting the section of the cat out. I was actually more convinced that you were right about the cat and I would find a clog after doing so.
I put too much faith in your description of the same symptoms and it's results and others who responded in kind. And I cut to many corners.

BigCajun

iTrader: (1)

A clogged cat can look good, they aren't always broken up or melted.
If you didn't see light coming through, it could have been bad.
Are you sure it wasn't?
The flashlight method is commonly recommended here by others besides myself.
If you're sure it was good, then I'll take some responsibility for it, but it's not bad advice, and I will continue to offer it to anyone who suspects their cat may be bad.