jmmarrero

rotor#1..5.2,4.8,4.7
rotor#2..5.05,,5.7,,,4.8
any suggestions its an 04 6speed i got it a year a go and i got to say its not the fastest car i have own but it is definetly the best and most fun to drive car that i have own and i dont want to sell it

alfy28

Do you know when the coils and spark were changed out? Those also are known reason for low compression. I would change those out then do a test again. either way good luck.

1.3_LittersOfFurry

iTrader: (4)

Ummm don't you mean de-carb? I don't see how changing the coils and plugs are going to increase the compression. Sure bad coils and plugs can lead to low compression, but changing them won't bring the numbers back up.

alfy28

Btw how many miles is on the car? also if you want to check to see if the coils are good or not, dozer made a DIY. Shouldnt take you long.

I know when i had low compression on my 04, it was due to coils and sparks needing a change out. SO i would start off with the small stuff first, then work your way up on possible reason for low compression and go from there. You would be surprised how a simple tune up fixes the problem . ALso I would change out the starter, if i remembered right , 04 has starters issues, but don't take my word, I changed out my starter when did my 3rd coil and swap maint. good luck

bse50

If it's beyond recovery just rebuild the damn engine or get a new one. The equation low compression = sale doesn't in my book...

alfy28

actually having weak coils is another reason for low compression test, at least according to japanese forums, but what do i know, i just didnt own a 2nd gen rx7 for 3 years before moving to the states from japan, then owning a rx8 for hte last six years, never learning basics for rotary troubles. Also i am glad you brought up Decarb, because I forgot to post that with my first post. So OP, like litter mentioned, I would do a search for DIY decarb first, but also check the coils

jmmarrero

the car has 75,677 miles..but ur right i better start on the simple stuff and work my way up,,and on the starte yeah my cuzin told me the same thing u did so ill chek that too..and if its beyond trust me ill rebuild it thanks guys

xexok

I don't understand how bad coils or spark plugs has anything to do with a compression test. When you do a compression test you disable fuel and spark while the engine is turning over so the coils or spark plugs should not have an effect on anything right? Maybe I am looking at it the wrong way, and if I am someone please let me know why.

alfy28

It's kinda of funny how a simple google search can do, why would a service bulletin by mazda tells you do all the thing that i posted, if the car has lower then normal compression, before performing determine a engine needs to swap out.
http://parts.arlingtonmazda.com/docu...21-10-2347.pdf
THe op doesnt need people to try to correct me, the OP needs solution ot fix his issue.

xexok

Sounds like the solution is a new engine to me. Yes dealers do ask you to change those parts first(not going to go into all the possible reasons here), but even if it were to somehow bring compression up a little bit it would still be low. The op really should post at what rpm the numbers were obtained though, that would help to know how bad it is.

Alfy when you had low compression did you actually get it tested, or was it just low compression symptoms.

1.3_LittersOfFurry

iTrader: (4)

I've owned 3 FCs over the course of 5 years before moving from Golden Meadow, La to New Orleans, La then owning a R-8 for a year. But what do I know?




They list those things (coils/plugs) because a weak ignition system leads to carbon build up, which leads to low compression. Changing the ignition out might help the car run better, but it will not increase the compression, only de-carb (maybe) or a rebuild will.

alfy28

I had it tested, because my friend flooded my car while visiting my parents back in okinawa. After i deflooded my car, my car didn't feel right so i had mazda do a compression test for me. It was low, so even though I had bought new plugs and decrabed my car when I was unflooding my car, I didn't change out the coils. When I took it in for a test, the tech asked me if I also changed out my coils (because they were over due) once i changed that out and had the tech redo my test, test was fine.

1.3_LittersOfFurry

iTrader: (4)

Easy, when you flooded the engine the gas removed the oil film from the engine. No oil film means poor sealing, which mean low compression. Drive the car for awhile, omp re-lubes the engine (premix also helps), compression returns. I flooded my first fc many times. Learned a lot from it.

De-carbing is kind different, the compression is low cause carbon is not allowing the seals to fit right, re-move the carbon the seal sit right, compression goes up.

Marc_GS

I just can't ignore this one.

Your compression results will NOT be affected by what coils are in the car. Bad coils, good coils, stock coils, aftermarket coils, even NO coils will just not affect the compression reading in ANY WAY! The compression test is a purely mechanical test. Rotor turns, sucks in air, compresses it and you measure that pressure. That's it! To indicate otherwise shows a fundamental misunderstanding of how engines (including rotaries) work, and is a great disservice to this forum. Hopefully this post will help someone someday avoid thinking that what you're saying is true.

What many believe to be true, and is theoretically possible, is that bad coils lead to poor combustion, which will lead to carbon, which willl lead to low compression. Getting new coils won't suddenly cure that.

xexok

Yep. Either way the OP needs to buy new coils and plugs for the new engine, but no point in him buying them now and giving him false hope that he may somehow save the engine.

I just wish the OP would post what RPM his numbers were obtained at still.

Squidward

It's been a while posting here, but I'll add my two cents to this, given I am in a similar situation.

I have an 04 RX8 w/ 131k on the odo. Still runs, however more recently, the engine has needed more turning to start up. It still idles fine, drives fine but on one occasion, it conked out on me at a red light. It was a rather warm day, so I do believe that sort of tipped the scales. The engine was found to have poor compression when I took her in for a checkup. My friend/mechanic said normal starting PSI should be in the 80's or 90's, but mine was starting in the low 30's. I have stopped driving the car hard many years ago (got it all out of my system in the first few years -- as well as a couple of traffic tickets!) so I hadn't realized how weak the RX-8 has actually become (my butt dyno has since recalibrated to my Evora).

Anyway, my mechanic basically said my engine is well past it's prime and so I'll need a new engine, or a rebuild.

Anyone know how much we're looking at here?

bse50

2.5\4k for a normal engine.