no comp on ONE side of the rotor? weird prob insues

[NOPSTNS]

i had this customer bring his rx8 in with a p0302 code, thats rotor 2 misfire to those who dont kno obd codes, and its been killin me for weeks. the prob i have is that it doesnt actually miss, it runs great, no rpobs, no bad idle, no lack of power, no hesitation or anything, but i can literally watch the misfire counter go up little by little as the car idles....

the first time he came in i took it as a usual concern, with the rx8s its the usual inspection of plugs and check for pcm issues.

the leadings were wicked fouledso i replaced them and reprogrammed the pcm.....drove it, no codes, shipped that sucker.....


12 minutes later he came back. i was like wtf, checked the freeze frame, happens normally at idle, fully warmed up, high load on the engine....

noticed a bad connection of leading plug wire for rotor 2, score! changed that wire......

2 weeks later hes back, mother F***.

i called the techline (always helpful, not sarcasm) and told them the story.

long story short...
they sent me a new pcm, the guy left and he came back when the pcm showed up, put it in, drove it, no probs, shipped it....

this was in earl;y aug......now hes back....and he aint happy.

i called techline, i sent the claim to regional and they sent out to field techs (trouble shooters) and they spent 3 hrs on it tryin to solve it.

now in my original diag, b4 gettin a pcm, they had me check so much stuff i literally dont want to post it all but kno that one of them was a compression test....heres what i got a 275 rpm on a hot engine

R1
8.5
8.6
8.5


R2
8.3
8.5
8.6

i ran the test again today after he put another 1k on the car, fron rotor was around the same but the rear rotor had some variance...

R2
8.6
8.4
8.1

one chamber dropped a tad now spec for variance allows 1.0 so it could be 8.5 and the other side be 7.5 and itd still be good but they said its enuff to cause a prob but not enuff to show performance issues.


SO THEY TOLD ME TO PUT AN ENGINE IN IT.


they are sayin one of the side seals must be bad bc its lettin out comp on one side. the three of us agreed it isnt an apex seal bc then ud have weak comp on at least two sides not just one.....a side seal must have let go and lettin combustion go past it.....

so i gotta order an engine....


any thoughts fellow rotary owners on the situation? low comp on ONE side is kinda weird to me.....??????????????????????????????????????

[Dave]

order new keep old success!

[95nracer]

There replacing a motor with those compression numbers!? I would just keep running that ****er. How is the oil injection system like on the 8? Anything like the 13b?


How does the PCM sense the misfire?

[NOPSTNS]

is the mop like the 13b?, um yeah, since the rx8 has a 13b......dont confuse the engine codes bro, it is a 13b as well, but i kno what u mean, the peripheral exhaust rotaries of yesteryear......the good ole days.....

the mop is pcm controlled, runs two lines to each rotor, each injector aimed slightly offset towards its corresponding side of the rotor housing. steps ranging from 0-60 with 0 being no injection and 60 basically a complete pour. the 04 05 and early 06s were tuned so lean on oil injection that some of the single oil cooler equipped 8s were boiling oil at idle in very high heat conditions and they werent gettin lubricated and the engines were droppin. there was a recall which involved reflashin the pcms to inject more oil, especially if the a/c was on. added oil consumption was not noticed by anyone, but ive tested it with the mazda computer and the mop actually flows more oil under these conditions. for 06 all rx8s got 6 port intake system and 2 oil coolers. added to the reflash they are now goood to go, still lean on oil burn if u ask me. they tune that out for emissions....weak


the pcm senses the misfire by the toothed ring behind the eccentric pulley. it has teeth in a certain order and a sensor at the 5 o clock position....the pcm looks at that sensor to see what teeth are where and if there is no spark where there is a tooth, booyah p0302 p0301 or p0300......

this particular one is readin a miss and the miss is so slight that u cant even feel it. suckers sensitive. dont even get me started on the knock sensor, u sneeze within 100 ft of the thing and itll pull 40 degrees right out from under ya!

imo 8.6 8.5 and 8.1 is not bad comp. i ran mine last month and im at mid to low 7s so mid 8s are glory days for my car..... spec new is high 8s so i dont see what the deal is, but they said the variance is just enuff foir no probs but enuff for CEL.....

whatever, they want me to put an engine in it....im still curious if any rotary guys ever had low comp on ONE side of a rotor b4, im young and only been workin at mazda for 2 yrs and all but, damn, thats new to me. usually u loose two sides if one (apex)seal is out or all three if two or more are out.....

i didnt kno what one low comp meant until today, seein a side seal go bad.....the car had the prob since new, which makes me wonder if it was assembled wrong, keep in mind the rx8 engines are hand built.....

[rotarychainsaw]

Maybe a tooth is bent causing the computer to think theres a misfire?

[NOPSTNS]

thats what i thought too, i checked the teeth with it off and with it running for damage, free play, or even if it was on straight. if its not on tight itll wobble when the engine is running causin the sensor to read some teeth but not others....
heres the list of what i checked, off the top of my head....

checked the resistance of
coils
plugs
wires
crank sensor

checked
spark plug gap
gap from crank sensor to teeth
pcm recalibration
cleared NVRAM
cleared KAM
ran comp test
multiple road tests to try to duplicate concern

replaced leading plugs
replaced leading wire to rotor 2
ran mop to full step to lube seals and retested compression

replaced pcm (1300 dollars later!)

car came back, time to call in the pros....

they spent a while on it, maybe 3 hrs, test driving, backprobing the connectors on the pcm, re road testing....
had me run another comp test after they beat it up to get it nice and hot....

rear rotor is coming up mid 8s all the time except for one side barely in the 8s im talkin 8.0 and 8.1 while the other sides are 8.6 or 8.7 the front rotor has a variance of .1 while the rear has a variance of .6 sometimes .7

so they told me to replace the engine......im still stumped how this happened, the car had the issue since new

[teh DIRT]

so whats the flat rate on it ?

[NOPSTNS]

R&R is about 8 hrs, maybe a tad less. a rebuild at the dealer (which never happens) pays double that....im pullin it from the top, u can do it either top or bottom but it seems easier to go from the top. when i worked at another mazda dealer (withholding name) we had a "master" tech condemm those damn engines like they were goin out of style, there was a recall concerning questionable compression on certain vin ranges and he was swappin them suckers 2x a week. the issue related mostly to cars in the hotter climates like texas and las vegas but he was a ****ing liar and he replaced them anyway.......i swear i saw him do 20 of em within 2 months time.....i saw bits and pieces of how they come out and it really doesnt look like much.....hed have the engine out and resinatll the new one and have it idling out back by lunchtime and get paid 10 hrs for it.....****in thief

then again, i havent done it yet....i talked it over with the service manager and he wants me to do it, i was beggin him to let me do it.....hes like whateevr dude, on the job training high five1

heres to hopin my team leader lets me

ive never pulled one before but im dying to learn!

[teh DIRT]

oh yous do the team thing, thats cool. Well good luck, hearing stuff like this makes me rethink not wanting to work for subaru. I could probably make a killing there.

[NOPSTNS]

no offense pete, i really like ya, but u prolly wouldnt make a killing. and its got nothing to do with U....

the industry is dead, there is no work, and young guys are the bottom of the totem pole when it comes to gettin the gravy jobs....i made some friends at tech school and we all left and went our seperate ways, the answer is the same from all of them, its slow....im makin 40 a week adn thats pushin it bc i get so much warranty work and bull**** work...no one pasy for maintenance anymore they just wnat done anything thats free....i had an inspection yesterday and the front brakes were 1/bonded which is fail in PA i also rec. wipers bc they were smeary and an oil change bc she was a qrt low.....and they turned down the job, they wanted to shop around for prices im like wtf, there went 3.5 hrs thats half my ****in day drivin away....

i am seriously thinking about quitting, moving to cali to pursue my dream of being a race car driver.....
i kid u not...


just ask terry, hes bored over at infiniti as well

[teh DIRT]

yeah I know about all of the cons. But im sticking with it, I plan on going back to school afterwards anyways.

[NOPSTNS]

small update, engine came, i pulled the engine and trans together from the bototm, wicked easy, the subframe isnt a full closed box so i didnt have to drop it, its only got three sides to it, like a horseshoe kinda, just front and both sides so the rear is a big hole where, magically, the einge can just come down from. i couldnt reach the top two bellhousing bolts so i just said screw it im droppin the whole thing.

pulled er out, swapped over the intake, oil nozzles, oil metering pump, and injectors with both fuel rails and slid er back up....

wicked easy, my first engine job and it was on a low mileage automatic rotary, doesnt get much easier than that!
paid 12 hrs but took me about 18, my boss is gonna pay me the other 6 so i didnt loose my ass on it. but im sure next time will go much quicker bc i wont try to reach the bell housing bolts and waste 2 hrs.

engien started right up and runs quiet and smooth in typical rotary fashion....

cars gone, see ya later! im sure they will buy it back for him and put him in a brand new car for all the trouble but it was an awesome learning experience!

now i am able to replace my engine WHEN it goes bad! yay!

[95nracer]

LoL, awesome. Good job :thumbup:



Now give me the old motor. :mrgreen:

[the mike]

Must be nice to get the other 6 hours. I had a job in last week that whooped my ass. I think I lost like 5 hours on it.

[NOPSTNS]

Must be nice to get the other 6 hours. I had a job in last week that whooped my ass. I think I lost like 5 hours on it.

i know the feeling bro, i once had a 93 rx7 that had a fuel line recall and i had to lift off the upper intake and replace the fuel lines and run an overlay harness and relays for the cooling fans and tap into the pcm for overlay BS. when i removed the upper intake manifold, about 20 vacuum lines that were once rubber but now hard as rock immediately vaporized into ashes.

i had to replace about 80% of the vac lines in a twin turbo rx7.

there is an entire book from mazda on the vac lines on the TT rx7. it is a 5 page layout of flip on flip on see thru pages that lay ontop of each other and create the whole system.

after breaking numerous solenoids in attempts to remove each vac hose off of them and waitng for the new ones to arrrive....

on thursday afternoon at around 330 pm i finished it up(mind u i started monday at 8 am) and started it up, ran fine, took her for a road test and after 5k the car took a big dump and u could hear the pressure bleed off like a BOV hissing it away. i went home that night, thought up a plan, and went to pep boys and bought a boost gauge....i went to work the next mornin, hooked up the boost gauge and went for a drive....most TT rx7s go 10-8-10 when it comes to boost...maybe a tad less depending on engine strength...this one went 8-0.........0.........0......nothing.....i took it inside and found the outlet house after the junction of both turbos (that connected to the intercooler) was loose. i must have forgotten to tighten the clamp....

i tightened it up and it ran like it gained 80 hp swear to god....i could finally breathe again....it was back to runnin awesome....(car had only 20k on the clock and it was a 93 and i did it just a few months ago)

the entire recall took about 20 hrs spread over 5 days and it paid......



THREEEEEE HOURSSSSS.

to top if off the guy came back and bitched that his coolant was low and that it was my fault, this was after we told him over the fone that his water pump was leaking and he said "i know".

he still denied it and blamed me.....after all that work i did.

which is why i trust no one and believe there is no good left in the human race.


i got stories i could go on forever man on how flat rate screws me, im too slow of a tech to sustain....not to sound c0cky but i do good and clean work, but its at the expense of speed.

i was once told, "before u can be good and fast u have to be good and slow"


i need a new career.........