Kim Jong Illest

2007 sunlight silver rx8 gt
50k kms on it



it was doing 4kpl/10mpg

changed wires coils plugs

don't think i will break 12 mpg

I usually drive @ 2-3k rpm occasionally goosing it at a stoplight.

starts hot and cold are both under a sec
i feel heat from the floor - bad cat?
a bit of a rough idle sometimes but I never see it hit 750 - always stays above.
will clean ess and reset it tonight? Will MAF cleaner work? My MAF is clean as a whistle btw - i think throttle body is ok too. Sorry about the digression; after cleaning the ESS with MAF I do the stomp, then start the car cold? Do I let it warm up b4 driving it? I usually rev it 2-2.5k for 30 sec before driving it.

thanks for your time & great forum

RIWWP

iTrader: (2)

You are killing your engine. stay above 3,000, and if you can stay at least around 4,000 it would be far better for the engine. Lugging it like that is carbon caking your engine. You may have already done irretrievable harm from uneven seal wear from carbon unseating the seals This engine needs to be driven hard (full throttle in gear) regularly, and even when not driven hard, it needs to keep the revs in the 3.5-5k range.

Yes, possibly. Pull the front of the cat down and look inside to see what is there.

You may have a vacuum leak too, but it might just be everything else that you are doing to damage the engine.

If you reset it, also disconnect the battery and leave that disconnected while you are cleaning it, so you can reset your fuel trims too.

MAF cleaner cleans the MAF. If your MAF isn't dirty, then it won't make a difference to the engine.

You can't start it hot. But start the engine, and let it idle itself warm, then let it idle for another 5 minutes at least. This helps relearn the idle speed fuel trims to keep it from stalling.

You don't have to make it get warm, but wait till the air pump stops, then go ahead and drive it. Use light throttle, like 5%-20% until the engine is warm. Light load driving is the best way to warm up a cold engine.

That isn't doing anything but wasting gas and time.

Kim Jong Illest

thanks for the quick reply

I guess there's a lot of misinformation being thrown around particularly on youtube. That's the source of the 25 sec warmup revving.

I've driven this thing 1,100km and I do red-line it occasionally I do like driving fast. I'll read on the vacuum leak however I've heard that's unlikely.

thanks I'll do this as well would lightly sanding the battery tips help too?

should have phrased this better. I meant cleaning the ESS with MAF cleaner.

great advice though I really appreciate it I am a bit overwhelmed with all the service kinda worried it might have a compression problem does that present with poor mileage before hot start problems?

RIWWP

iTrader: (2)

Um, yes. Never trust youtube commenters. Some of them are valid, but largely it is a bunch of people that have no idea what they are looking at and may not even actually have an RX-8. Even videos from owners are often wrong and/or unclear.

Stick to this forum. If someone has an issue with anything I'm telling you, they will point it out and the discussion will be the open. We tend to correct each other rather well here, so the information will be more solid, and FAR more reliable than YouTube (or any other social media)


Driving fast is different than driving hard. You can do 100mph in 6th gear at 5,000rpm, but that isn't driving the engine hard. In fact, it's pretty happy and relaxed there. You can go full throttle to redline in 1st gear and only hit ~40mph. Hardly fast, but the engine is being driven harder.

You can if you feel a need. Just being clean is the main point. They corrode quickly and you need all that corrosion gone.

Use a rag. The ESS is just a magnet covered by plastic, you don't need special chemicals, and MAF cleaner won't remove anything metallic that is stuck to it via magnetism. That is what you are really trying to remove, any metal particals on it. It can be oil coated and still produce a strong signal, since oil isn't magnetic.

Literally every single possible thing that can go wrong with the drivetrain will reduce gas mileage. If you have good gas mileage (20-24mpg 100% highway) then you know that everything is good with the engine and drivetrain. When it drops, it could be literally anything though. Gotta work through it methodically.

Kim Jong Illest

I thought I'd give an update. Cleaned ESS and did 20 brake stomp. Don't think it helped the hot idle.

Driving it harder all the time definitely eats more gas I guess I won't know for sure until I finish a new tank but currently it seems like I'll get 9 mpg or so city only driving.

That's pretty bad right? Should I continue driving it in this condition?

RIWWP

iTrader: (2)

Have you finished all the other checks, inspections, and solutions?

9mpg sounds like a clogged cat, which can lead to engine damage and a car fire.

Kim Jong Illest

Things I've done:

Replaced plugs, wires, coils. (I bought the car with rough idle and OBD showed that there were stored misfires even though I had never seen a blinking CEL or any CEL for that matter). I was also having a bit of trouble starting hot and cold sometimes where it would take up to 3 secs. Since the change I have only had 1 slow start when it was hot and took about 2 secs. Normally it runs after what sounds like 3 turns. The coils/plugs were definitely bad. One of the wires had burnt itself onto the old IG coil. After the change there was a noticeable improvement in acceleration, coasting and gas mileage, and idle.

Cleaned MAF, visually inspected throttle body. Cleaned ESS and did 20 brake stomp.
I checked wheels for brake dragging; i think alignment is ok as it drives straight with my hands off the wheel. The car was inspected at purchase on November 15th by a non-specialist mechanic and got a clean bill of health. When I drove it back to my province it passed and OBD emissions test with no problems. I would assume that if the cat was clogged I wouldn't have been able to pass emissions.

I still have to test the vacuum system, I will be buying a pressure gauge today and seeing what I can do. I'll also try to seafoam.

Coolant system is probably overdue at 50,000km but I'm not sure where I should throw my next chunk of money. Kind of leaning towards a compression test now rather than firing in the dark.

I've gotta change the air intake filter, car came with mazdaspeed cold air intake ( i hear it sucks, I know - i think they packaged the 2007 rx8 with it from the dealership).

Prolly needs transmission fluid change but I don't think that will help with my MPG.

Main suspects now are CAT and Vacuum leak.

RIWWP

iTrader: (2)

Bad assumption. A clogged cat still filters the exhaust it lets through.

Just look at OBD2 at a hot idle. MAF and fuel trim data will indicate if you have a vacuum leak or not. IF you do, then you can go hunt for it.

The only viable place to use seafoam is in the gas tank, where it will slightly strip carbon from inside the engine over the course of a tank. Letting it sit in the engine does nothing. I proved it with before and after borescope inspections. Ingesting it with the engine running works well, but then distilled water is just as effective for 80 times cheaper.

Good idea.

The MS intake is one of the 3 good ones. Keep it. Mazdaspeed, AEM (they are the same), and Racing Beat.

Kim Jong Illest

Thanks so much RIWWP!

ESS clean/reset seems to have fixed my hot idle. I guess it dipped the last time when I took the car out for a late night drive right after the reset.

Had my car jacked up and mechanic said that bolts are pretty rusted on it and it might break if he tries so I will have to come back with the appropriate replacements if I wanna do this or do it myself; weather permitting on the weekend. If anyone happens to know the bolt size just throw it out there.

Just finished my tank @ 235km/50L = 4.7kpl or 11.055mpg about half of it was always staying above 3.5kRPM. All driving was city.

With the jumpy idle issue gone

I have only the following symptoms left:

High gas consumption
Rich gasoline smell from exhaust, really rich at startup

• highway gas mileage less than 17mpg
  • Ignition failure <---- changed coils,wires, plugs, is there anything else? Could it be the battery? Is there anything else?
  • e-shaft sensor fouled <- cleaned
  • engine compression loss <- maybe but no power loss, quick starts
  • vacuum leak <- does it always present with rough or unstable idle?
  • front O2 sensor failure <- b4 the cat? Always CEL?
  • MAF fouled <- cleaned
  • dragging brakes <- checked
  • old transmission oil <- maybe, 50k km I didn't think it could make it this bad. There's a bit of hesitation switching into a gear, not debilitating. Surprisingly though sometimes, I have no trouble at all and actually feels really quick and smooth usually when the car has cooled down a bit after just getting warm, like the second notch on the temp guage.
  • old diff oil <- maybe
  • failing diff <- maybe
  • carbon choked engine <- maybe, is there power loss with this?

RIWWP

iTrader: (2)

The front bolts are M10. Go to advance, pep boys, or autozone, go to the exhaust hardware section, and find M10 studs. They will all be the right thread pitch, either 1.25 or 1.5. You need 6 nuts and 3 studs total for the front. And yes, having someone with a torch, a lift, and power tools is best to remove rusted cat bolts. Don't expect to keep them, expect to replace them. I would replace mine every year, just to make sure I never had them rust on again. The first time it cost me $20 for a local corner shop to torch them off and replace with the stuff i gave them.

Legot

iTrader: (1)

Seems like cat failure. Carbon choking is likely if you don't drive it hard, but if your cat is clogged then there's no way you're going to get that carbon out (it will also build up MUCH faster).

Kim Jong Illest

carquest had the M10's right beside my work

these are on mine stock

04-11 Rx8 Main Catalytic Converter Front Stud...

I guess the M10's will fit both sides

I have found a used racing beat midpipe locally for $150 I think I will pick it up tomorrow rather than getting the compression test they charge at least 2 hours min comes out to $217

oh and i hooked up my odb2 and went for a 15 min drive



looks like while cool the cat is fairly responsive, then i can see a gradual degradation of efficiency, do you concur?

Kim Jong Illest

ok, M10 1.5's didn't fit.

still got it off and replaced it

it did not look damaged at all, it's a good thing that I grabbed that midpipe because I felt a difference immediately. I would have probably been chasing other problems seeing as how it didn't look blocked nor did it rattle.



no cel with the midpipe too really weird... driven about 40km so far and I can see that the mileage is getting good.

this midpipe tho..... It sounds really baaaaaaaaaad when the throttle is down more than 30%, It's usually buzzing in the 4-5k rpm range.

Either way I appreciate everyone's help it's definitely running better.

https://www.rx8club.com/series-i-tro...mptoms-241859/

found this thread seemed similar to the problems im having so I tracked him down and made him update the thread check it out.

Gravey

iTrader: (3)

^You can get a resonated midpipe from BHR and/or Racing Beat to get rid of the chainsaw mating with a tin shed effect!

Black Halo Racing Resonated Midpipe | Black Halo Racing

REN.V2 Race Pipe for 04-11 RX-8 - Racing Beat

RIWWP

iTrader: (2)

That is partially clogged. Look at the difference between the lower right and the upper left. Upper left is still got some clear cells, the lower right is all clogged.

The light will show up eventually, but it is possible that it will take a really long time for the ECU to figure out that the cat is gone. I think it took mine something like 6,000 miles before it finally popped the P0420 code.

Yes, there is only one midpipe that doesn't buzz, rattle, drone, blow out, fail, or melt. Some people think i'm a fanboi for having this opinion, but it's really just that only one company bothered to actually design the midpipe internals for a rotary: BHR

Time and time again I see people on the forum buying a cheap midpipe to save money, and end up hating the noise it produces, and eventually getting the BHR midpipe anyway, costing them more in the long run than just getting the BHR to begin with. I put 55,000 miles on my BHR midpipe before selling the car, and the new owner of the midpipe has put another 20k or so on it, and it still sounds the same as the day i bought it, no buzz, rattle, drone, no failures.

Gravey

iTrader: (3)

^I am trying to keep mine as close to stock as possible and I am having a hard time trying to convince myself NOT to get one. I think come spring I will be contacting Charles to see what he has for the series 2.

Kim Jong Illest

that's just the angle of the pic

https://dl.dropboxusercontent.com/u/...8/VID_0063.mp4
https://dl.dropboxusercontent.com/u/...8/VID_0063.flv
sry about the shaky vid just balancing these 2 at the same time

Khurram

I concur RIWWP on BHR's quality, i had mine for 7 months and 45k kms on it. No issues what so ever.

Gravey I just sold my BHR Midpipe for $500.

Kim Jong Illest

Guess I spoke too soon - my mileage got a bit better but marginally. maybe 10-20 extra KM.

No idea what to look for now so I scheduled myself in for a compression test and engine diagnostic at the stealership for this Wednesday 9AM - after calls to 5 different stealerships I found one that will do the C-test for $110.

Leftover Symptoms:

Low Mileage -> OBD2 Tool says I am getting 16-19MPG city driving realistically I am getting 10-12
Rich Smelling Exhaust -> maybe because of DE-CAT?
Idle dip after stopping at light (intermittent) When MAF sensor falls to 4 from 50+ at a stop my Short Term Fuel Trim will shoot up to +15 during the idle dip. There are no stored misfires

Kim Jong Illest

Instead of the Mazda dealership I sought out ThWord from RX7Club, really knowledgeable guy - he has a 20B RX7 and is apparently the only east coast Canadian tuner. after telling him everything he sprayed brake cleaner looking for a vacuum leak then he took it out for a drive with his laptop hooked up and determined that it was a faulty coolant temp sensor. Charged me $140, I just drove it home - the power delivery felt smoother and the needle didn't drop like crazy on my trip back.

So it was running really rich I can already smell the difference - the idle is less shaky too.

In either case I'm pretty happy I'll see how I do on mileage he told me not to get a compression test as he felt that the mileage was too low to warrant it considering it has no starting problems.

Maybe I'll do the test at a later date as I've still gotta buy other maintenance items.

RIWWP

iTrader: (2)

Glad you got it solved. ECT sensor failure isn't common, but it has happened. And it would certainly cause problems with driveability.

Kim Jong Illest

add it to your sticky list of symptoms and solutions. I don't think it's there and it's easy to test for anyone with a OBD2 tool.

this link looks pretty helpful and covers troubleshooting low gas mileage

http://www.rotaryheads.com/PDF/RX8/2...Problem%20.pdf

Khurram

So did you end up replacing the Coolant Temp Sensor?
Or did he just sort of blocked (masked) it from his laptop?

Kim Jong Illest

he replaced it

Gravey

iTrader: (3)

Wow!!! Isn't that basically what it costs new?!? that's pretty awesome!