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So it was all good and i was turbo'd.... and then i blew my engine.

Old Nov 19, 2012 | 01:05 PM
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So it was all good and i was turbo'd.... and then i blew my engine./edit: runs again!

Well it sucks but I believe I blew the motor on my RX8... I was data logging it in an attempt to get my 2nd tune from MazdaManiac and it went. Was doing a pull to redline for the log... the car was running alright up to that point, some misfiring in the 7.5-9k rev range when i really got on the gas. I was probably pushing it trying to make it to redline when the car just super bogged down on the highway around 8.5k. Took it to neutral and the motor died and i pulled over to the side. Car wont idle by itself, and it runs and sounds all kinds of messed up when i attempt to rev it up and hold it there...

Now from those with experience with blown motors, what aspect of the engine you think probably failed ? Could it be something as simple as an apex seal bent out of shape causing it to not run right ? I know I've read that when the seals go they usually shatter and scrape up the rotor housing and all. When I rev it I dont seem to hear any type of sound coming from the inside that would indicate shattered pieces ? or could it be some other aspect of the engine that could have failed do to the high boost and misfiring ? Appreciate the feedback.......... kinda sad, but somehow always felt like this day was going to come. Also looking into motor replacement options, if anyone has any recommendations please let me know.

Last edited by Rotary_Redliner; Nov 23, 2012 at 07:23 AM.
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Old Nov 19, 2012 | 01:14 PM
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My car isn't turbo'd but experienced same symptoms when my motor died after overheating. Not sure what the damage was I just bought a new engine and used it for a core charge. What turbo kit are you running?
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Old Nov 19, 2012 | 01:33 PM
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why weren't you watching AFR?
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Old Nov 19, 2012 | 01:40 PM
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All too common - sorry to hear another renny has died .
Quickest way to tell if it's blown - take spark plug out of the rear housing and turn over the engine . Listen to the pulses , you should hear 3 strong pulses not one strong then 2 weak . Check other chamber if it's not obvious.

I am a firm believer in aftermarket apexs seals for this engine when it's FI'd .
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Old Nov 19, 2012 | 01:47 PM
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Originally Posted by winglebeast
why weren't you watching afr?

+1.
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Old Nov 19, 2012 | 02:00 PM
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you could have done something as simple as fouled a spark plug, check plugs and ignition.


stories like this are why I am a firm believer in "step" tuning, tuning each variable one at a time prevents wot pulls using your 1st tune. For the life of me I cant make sense of this method

Last edited by Chris; Nov 19, 2012 at 02:06 PM.
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Old Nov 19, 2012 | 02:20 PM
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I was watching AFR's and they never got above 11.. ( I think that is the lowest the cobb reads correct ?) I will take inspect the spark plugs and turn over the engine... I have the BHR coils.

Winglebeast it is your old Greddy kit btw, with an upgraded BNR turbo.
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Old Nov 19, 2012 | 02:36 PM
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the whole time you never get above 11 AFR???????????
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Old Nov 19, 2012 | 02:51 PM
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that is correct. when I gave it gas it would immediately drop to 11 and stay there.
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Old Nov 19, 2012 | 02:58 PM
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wow, very very rich then, chances are you ruined a spark plug or two
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Old Nov 19, 2012 | 03:03 PM
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...this is why I am seeking some help from people that have actually popped their engines from being too lean. I knew my car was running super rich since Ive started the turbo tuning, because the car chokes from the fuel if i give it quick gas, I can smell it also. I also thought being rich would prevent the engine from blowing. I will have to check my plugs and see.
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Old Nov 19, 2012 | 03:09 PM
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Yeah if you are seeing low 11's (11.16 or so is where it bottoms out) chances are you are way richer than that and fouled your plugs. What plugs are you running?
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Old Nov 19, 2012 | 03:10 PM
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at least you didnt have a coolant cap failure causing one of your coolant seals to fail
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Old Nov 19, 2012 | 03:18 PM
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I changed the plugs to the NGK 5255 (bur9eqp) in all 4 spots because I read that is what some other turbo owners do... ?
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Old Nov 19, 2012 | 03:31 PM
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make sure you space them accordingly. the rx7 plugs sit deeper then the rx8
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Old Nov 19, 2012 | 03:38 PM
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Originally Posted by Rotary_Redliner
I changed the plugs to the NGK 5255 (bur9eqp) in all 4 spots because I read that is what some other turbo owners do... ?
I only run the bur9eqp in the leading position. The trailings are stock. Make sure you spaced them correctly as Chris mentioned.
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Old Nov 19, 2012 | 03:48 PM
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Originally Posted by Chris
you could have done something as simple as fouled a spark plug, check plugs and ignition.


stories like this are why I am a firm believer in "step" tuning, tuning each variable one at a time prevents wot pulls using your 1st tune. For the life of me I cant make sense of this method
Or poped a seal on a pipe to/from the IC. Had that happen when I upgraded my IC, turned out to be a lose fitting. fingers crossed that it is something cheap
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Old Nov 19, 2012 | 04:04 PM
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Yeah definitely check the simple stuff, if a coupler blew or a pipe blew off the engine would have sounded like it took a ****.
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Old Nov 19, 2012 | 04:05 PM
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It's in the instructions right there... once you had a misfire, need to stop! Those extra few 1000 RPM is not going to be worth it just for the log

1) Plug your AccessPORT into the RX-8 and start the car. Allow it to warm up thoroughly.
2) Select "Monitor" from the menu options. Press the "OK" button.
3) Select "Set Data Log List" from the "Monitor" menu. Press the "OK" button.
4) check ONLY the following option check-boxes:
· Equiv. Ratio
· Calculated Load
· Long Term FT1
· Mass Airflow
· RPM
· Short Term FT1
· Vehicle Speed
· Accel. Pedal Position
· Ign. Tim. Lead
· Ign. Tim. Separation
5) Press the "Back" button then press the "OK" button.
6) Select "Data Log" from the "Monitor" menu. Press the "OK" button
7) Scroll to the Equiv. Ratio display to monitor your air-fuel ratios during logging.
8) Press the "OK" button again to start the data-log.
9) After approximately 10 seconds, press the "OK" button again to stop the data-log. You have just created your first data-log of the engine's idle performance.
10) Take your RX-8 to a safe section of relatively flat highway where you can get the vehicle up to 4200 RPM for several miles at a time without being disturbed. On manual transmission-equipped vehicles, this will be performed in 4th gear. On 4-speed automatic transmission-equipped vehicles, this will be performed in 2nd gear. On 6-speed automatic transmission-equipped vehicles, this will be performed in 4th gear.
11) Once you are up to 4200 RPM, turn on your A/C, headlamps and rear defroster and set the cruise control to hold your speed. On vehicles with no cruise control, hold the vehicle speed as constant as you can with the gas pedal.
12) Press the "OK" button again to start the data-log and continue to cruise for a minimum of 30 seconds.
13) Press the "OK" button again to stop the log.
14) Again, on a safe section of open, flat highway, lower your RPMs to 3000 in 2nd gear (1st gear on the 4-speed automatic).
15) Press the "OK" button again to start the data-log and accelerate at WOT to redline. On boosted applications, ease into full throttle and observe your Equivalence ratios. If the Equivalence ratio is above 12:1 at RPMs over 4200, back off the throttle and proceed to the next step.
16) Release the gas pedal and allow the vehicle to slow and your RPMs to drop and switch to 3rd gear (2nd gear on the 4-speed automatic).
17) When your RPMs have dropped to 3500, once again accelerate at WOT to redline or to the highest safe speed you can attain. On boosted applications, ease into full throttle and observe your Equivalence ratios. If the Equivalence ratio is above 12:1 at RPMs over 4200, back off the throttle and proceed to the next step.
18) Press the "OK" button again to stop the log and return to your starting location.
ON BOOSTED APPLICATIONS – IF YOU OBSERVE EQUIVALENCE RATIOS (AFR) ABOVE 12.0 AT RPMs OVER 4200 OR HEAR AUDIBLE RATTLE KNOCK, IMMEDIATELY RELEASE THE GAS PEDAL AND DO NOT ATTEMPT ANOTHER WOT PASS UNTIL CONTACTING MAZDAMANIAC.
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Old Nov 19, 2012 | 10:21 PM
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sorry--but I think it will end up being blown--it takes a lot more than the proper a/f ratio to prevent detonation. What was your leading timing at the time it happened?
Hell I have a/f's in the high 10's and I have never fouled out a spark plug. You have a good ignition system in place also.
I will cross my fingers that I am wrong!
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Old Nov 20, 2012 | 06:12 AM
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I highly doubt this is a simple fouled plug from running rich. I ran my turboed car hard pegged rich for MONTHS and the plugs were fine. By all means, check the plugs. But my personal guess is you popped it =/

Only other possibility is you killed a coil..but your symptoms dont sound like the usual coil deal =/
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Old Nov 20, 2012 | 08:52 AM
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So I took out the spark plugs and all 4 were black and soaked with fuel.... Definitely think they're bad. Also found a coupler that came apart. Fingers crossed that once the new plugs come in 2 days it'll be running again..
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Old Nov 20, 2012 | 09:36 AM
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Originally Posted by Charles R. Hill
When this combo is used in this fashion, spacers/shims are not needed.
Yeah I should have clarified on the last part of my post, I meant to make sure they were spaced correctly since he was running the 9's all the way around.

Originally Posted by Rotary_Redliner
So I took out the spark plugs and all 4 were black and soaked with fuel.... Definitely think they're bad. Also found a coupler that came apart. Fingers crossed that once the new plugs come in 2 days it'll be running again..
A blown coupler will definitely create some issues. Don't over tighten the clamps, it's very easy to warp the piping that way and you can actually spray a bit of high strength hair spray on the ends of the pipe before you put the couplers on and that will help slip them on easier and hold them in place once the hair spray dries.
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Old Nov 20, 2012 | 10:46 AM
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if you blew a coupler and the plugs are bad then there is your answer
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Old Nov 20, 2012 | 12:57 PM
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Originally Posted by Chris
if you blew a coupler and the plugs are bad then there is your answer
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