Loss of power & rattle, help!
06-11-2011, 03:48 PM
#76
'04 Mazda RX-8
Good evening chaps,
I'm posting from the other side of the world in the hope that you fine people can help with an engine issue on my 2004 RX-8 192.
There's a thread on the UK forum here:
http://www.rx8ownersclub.co.uk/forum...p?f=19&t=32300
Boils down to a loss of power between 6,000 to the limiter, only when hot. There's a rattle that comes with it (trying not to use the M, I, A or C words
)
Short video of the noise while running against the brakes in first - you will need the speakers up loud though. You can hear it most as the revs come back toward 6,000. It's much clearer in real life instead of phone-video.
http://www.youtube.com/watch?v=4ODPL1utFnM
Pete.
I'm posting from the other side of the world in the hope that you fine people can help with an engine issue on my 2004 RX-8 192.
There's a thread on the UK forum here:
http://www.rx8ownersclub.co.uk/forum...p?f=19&t=32300
Boils down to a loss of power between 6,000 to the limiter, only when hot. There's a rattle that comes with it (trying not to use the M, I, A or C words
)Short video of the noise while running against the brakes in first - you will need the speakers up loud though. You can hear it most as the revs come back toward 6,000. It's much clearer in real life instead of phone-video.
http://www.youtube.com/watch?v=4ODPL1utFnM
- Plugs are new, gaps right, new coil packs, new Magnecor leads. Wired up right.
- CAT looks like brand new, have dropped it out and looked in.
- Have run Cataclean through, which helped a little but the issue quickly came back.
- Cold and hot starts are quick, never been an issue.
- I always run 97 or 99 RON fuel.
- All recalls up to date.
- SSV and VDI actuators work fine with vacuum applied and give different faults to this if disconnected.
- Ran 100ml of Redex through each rotor as a carbon remover, no change.
- Heat shields are fitted and intact, the one loose one now is held on with two stainless steel jubilee clips.
- Have tried an ecu reset as well as the 20 brake press reset, no change.
- I don't think it's water rushing/gurgling through the heater as there is a power loss accompanying it.
- MAF and IAT sensors are clean and give expected figures through the diagnostic kit.
Pete.
06-13-2011, 12:28 PM
#77
UPDATE:
Summary of what I've done:
Coolant changed
Oil changed
Transmission fluid changed
Differential fluid changed
spark plugs have 15000km only, coils the same.
Radiator fans working
MAF cleaned (no oil blowback)
Intake filter checked (clean and not oily everywhere)
Throttle body cleaned
battery voltage checked.... 12.7 to 12.8 when engine off
alternator output anywhere between 13.6 and 14.1. It tries to maintain 14.1, goes to 13.6 whenever something has just started for a brief second or so.
one (1) can of BG44K ran into the tank.
I swapped the coils back to my old set which were NOT failed (no CEL). I wanted to see if the current set with 15,000km had gone bad. The old set had 70,000km on them. The result is the same. Also before I said the noise appears when the temps are above 90C, well that's also not true because it happened when it was back down to 82 - 85C as well.
Noise starts happening around 5000 - 6000 under load at WOT. If you were to drive with light throttle in those RPMs, there is NO NOISE. The noise only happens after driven for awhile.
AFR's are 15.1 or so at idle
14.7 at cruise
Engine has vibrations that travel into the cabin. I opened the hood and turned the A/C on at idle to watch it cycle on and off. The whole engine shakes a lot when it turns on. Is that normal?
Again, I have NO CELs.... I'm down to the following which I think are relavant:
1) dying CAT (no glowing red though)
2) bad engine mounts (nothing to do with the powerloss issue, but nonetheless is bad)
3) overheated fuel pump? (but it does that when the gas tank is full too)
4) low compression, new engine required? (But I don't have idle problems or random stalls)
Summary of what I've done:
Coolant changed
Oil changed
Transmission fluid changed
Differential fluid changed
spark plugs have 15000km only, coils the same.
Radiator fans working
MAF cleaned (no oil blowback)
Intake filter checked (clean and not oily everywhere)
Throttle body cleaned
battery voltage checked.... 12.7 to 12.8 when engine off
alternator output anywhere between 13.6 and 14.1. It tries to maintain 14.1, goes to 13.6 whenever something has just started for a brief second or so.
one (1) can of BG44K ran into the tank.
I swapped the coils back to my old set which were NOT failed (no CEL). I wanted to see if the current set with 15,000km had gone bad. The old set had 70,000km on them. The result is the same. Also before I said the noise appears when the temps are above 90C, well that's also not true because it happened when it was back down to 82 - 85C as well.
Noise starts happening around 5000 - 6000 under load at WOT. If you were to drive with light throttle in those RPMs, there is NO NOISE. The noise only happens after driven for awhile.
AFR's are 15.1 or so at idle
14.7 at cruise
Engine has vibrations that travel into the cabin. I opened the hood and turned the A/C on at idle to watch it cycle on and off. The whole engine shakes a lot when it turns on. Is that normal?
Again, I have NO CELs.... I'm down to the following which I think are relavant:
1) dying CAT (no glowing red though)
2) bad engine mounts (nothing to do with the powerloss issue, but nonetheless is bad)
3) overheated fuel pump? (but it does that when the gas tank is full too)
4) low compression, new engine required? (But I don't have idle problems or random stalls)
06-13-2011, 01:42 PM
#78
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Mine worked fine until the engine warmed up, then it'd stick and I'd get the "raspy" noise and a flat spot in power from 3,500+, and generally only noticable at full throttle.
06-13-2011, 02:07 PM
#79
The SSV is something I'm reluctant to check. I saw JON316G's video on how to remove it, it looks like a pain in the *** to remove and check....
is there no way around it? Will seafoam clear the SSV? My last option really is to take on the huge task of removing the SSV. The video just scares me removing all those items.
is there no way around it? Will seafoam clear the SSV? My last option really is to take on the huge task of removing the SSV. The video just scares me removing all those items.
06-13-2011, 02:14 PM
#81
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My dealer replaced it after replacing the engine, and yes... no more rasp and no more power flat spot. He at first thought the SSV was fine, as he could move it freely by hand I believe before the engine was replaced, BUT that was on a cold engine.
Once the new engine went in and they were testing it, he noticed the SSV stuck when hot.
Once the new engine went in and they were testing it, he noticed the SSV stuck when hot.
06-14-2011, 02:25 PM
#83
Okay, I inspected the SSV and VDI without removing anything. I simply took a long screwdriver and tried to move the valves. They all move freely and returns to their original position fine without slowing down or anything. The SSV makes a little squeak though as its moving. The VDI does not.
I guess having done this, I don't need to remove it to see if its gummed up then.
I'm trying a can of seafoam in the 1/2 a tank of fuel right now. I think I will try the induction method of mazda zoom zoom cleaner next.
I guess having done this, I don't need to remove it to see if its gummed up then.
I'm trying a can of seafoam in the 1/2 a tank of fuel right now. I think I will try the induction method of mazda zoom zoom cleaner next.
06-14-2011, 02:47 PM
#84
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06-15-2011, 03:07 AM
#86
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Reason I'm going for a manifold change is the looseness of the SSV. You can feel quite a bit of radial and axial play in it, plus it makes quite a knock when you move it about:
http://www.youtube.com/watch?v=UahOn-XS_m4
http://www.youtube.com/watch?v=UahOn-XS_m4
06-15-2011, 09:22 AM
#87
Okay, I inspected the SSV and VDI after the morning drive. Engine is hot.
Both move freely using a long screwdriver, and return to their positions when let go. This rules out that I have a stuck SSV or VDI.
Manicmechanic, are you saying that the loose SSV is contributing to your rattling sound? Or are you guessing that this is whats causing the noise?
Both move freely using a long screwdriver, and return to their positions when let go. This rules out that I have a stuck SSV or VDI.
Manicmechanic, are you saying that the loose SSV is contributing to your rattling sound? Or are you guessing that this is whats causing the noise?
06-15-2011, 09:44 AM
#88
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The noise it makes when you shake it by hand sounds just like the rattle you get on the move. Plus when I rigged up a bodge with some rubber bands to pull the SSV away from the manifold slightly in use, the noise lessened noticeably.
06-15-2011, 02:45 PM
#92
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Manifold arrived today - took two months to get here from Idaho via Canada!
Probably be fitting it in a couple of weeks when I've got some holidays. Need to get gaskets and seals too.
Probably be fitting it in a couple of weeks when I've got some holidays. Need to get gaskets and seals too.
06-19-2011, 09:21 AM
#95
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A few more observations made from running with the Ultragauge fitted.
Lambda voltage is around 0.8v flat out, so not running weak - fuel pump should be ok.
Ignition advance runs around 25' and doesn't back off when rattling, suggesting it isn't detecting pinking - backed up by Haywards diagnosis.
Mass air flow peaks at around 175 g/sec when the car is warm, but not hot. When the rattle occurs, WOT air flow drops as low as 130 g/sec at the same RPM/load.
Water temp runs around 185 - 200'f (85-93'c) whether cruising or caning the bejesus out of it.
CAT temps run around 1500'f (815'c) at cruise to an absolute max of 1735'f (945'c) when at full load.
I'm really guessing now, but decreased air flow suggests the engine can't draw any more in because:
..Exhaust under pressure is being forced back up the intake as the port opens as it can't escape through the exhaust, causing the rattle on the SSV and VDI
..or compressed mixture from the compression cycle is leaking past the seals back into the intake cycle chamber.
..or some random fluttering of the SSV/VDI valves occur sometimes when hot, limiting the air flow. There is a distinct shiny worn dimple in the SSV actuator arm, suggesting it has either hit the stop a lot very hard or may be chattering. Gonna try jamming it full open and see what happens.
Any clues, even odd sounding ones, are welcome. I may even resort to changing the oil injection lines and nozzles when I'm doing the lower intake manifold swap. Another pop at premixing should prove or rule this out though.
Lambda voltage is around 0.8v flat out, so not running weak - fuel pump should be ok.
Ignition advance runs around 25' and doesn't back off when rattling, suggesting it isn't detecting pinking - backed up by Haywards diagnosis.
Mass air flow peaks at around 175 g/sec when the car is warm, but not hot. When the rattle occurs, WOT air flow drops as low as 130 g/sec at the same RPM/load.
Water temp runs around 185 - 200'f (85-93'c) whether cruising or caning the bejesus out of it.
CAT temps run around 1500'f (815'c) at cruise to an absolute max of 1735'f (945'c) when at full load.
I'm really guessing now, but decreased air flow suggests the engine can't draw any more in because:
..Exhaust under pressure is being forced back up the intake as the port opens as it can't escape through the exhaust, causing the rattle on the SSV and VDI
..or compressed mixture from the compression cycle is leaking past the seals back into the intake cycle chamber.
..or some random fluttering of the SSV/VDI valves occur sometimes when hot, limiting the air flow. There is a distinct shiny worn dimple in the SSV actuator arm, suggesting it has either hit the stop a lot very hard or may be chattering. Gonna try jamming it full open and see what happens.
Any clues, even odd sounding ones, are welcome. I may even resort to changing the oil injection lines and nozzles when I'm doing the lower intake manifold swap. Another pop at premixing should prove or rule this out though.
06-23-2011, 05:11 AM
#96
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Thanks to advice from this and the UK forum, I think I might finally be getting to the bottom of this.
Chucked 150ml of 2 stroke oil in with a tankful of petrol and the problem appears to have gone away completely. Granted it hasn't been screaming hot weather recently, but the car idles and drives much smoother - plus the mass air flow g/sec is improved at higher rpm. I'm showing 150-160g/sec at 6000 revs where it was only seeing 140 before. Peak air flow looks to be 170g/sec, but it will bounce higher as you slam carelessly into the rev limiter...
Previous attempts at premixing weren't good, but I have changed a few parts since then including most of the ignition system!
So it looks like it's a lubrication / oil injection fault.
It's early days to close the book on it completely for me, but in 100 miles it has been perfect.
Chucked 150ml of 2 stroke oil in with a tankful of petrol and the problem appears to have gone away completely. Granted it hasn't been screaming hot weather recently, but the car idles and drives much smoother - plus the mass air flow g/sec is improved at higher rpm. I'm showing 150-160g/sec at 6000 revs where it was only seeing 140 before. Peak air flow looks to be 170g/sec, but it will bounce higher as you slam carelessly into the rev limiter...
Previous attempts at premixing weren't good, but I have changed a few parts since then including most of the ignition system!
So it looks like it's a lubrication / oil injection fault.
It's early days to close the book on it completely for me, but in 100 miles it has been perfect.
06-23-2011, 06:50 AM
#98
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I'm not so sure. Compression test:
They carried out a hot compression test with the following results at 230 rpm:
Front 7.5, 7.6, 7.5 bar
Rear 7.8, 7.9, 7.8 bar
Front 7.5, 7.6, 7.5 bar
Rear 7.8, 7.9, 7.8 bar
06-23-2011, 07:15 AM
#99
Are you 100% sure that they prformed it properly? Contact Shifty to know how his second test looked like. Don't be stubborn!
Premix generally band-aids the situation when the apex seals aren't perfectly flat because it makes a taller film. The key word being "band aids". 150gr on 50l is nothing, try 200\220grammes.
Premix generally band-aids the situation when the apex seals aren't perfectly flat because it makes a taller film. The key word being "band aids". 150gr on 50l is nothing, try 200\220grammes.
06-23-2011, 08:09 AM
#100
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I'm planning on trying different amounts, in honesty I feel I should use less rather than more if it still runs ok. 125ml oil for 45 litres fuel is what I've seen recommended when using Protek-R.
Compression test was carried out by a well respected rotary specialist called Hayward North.
Priced up new oil injectors and lines. Over 400 GBP, wow.
Compression test was carried out by a well respected rotary specialist called Hayward North.
Priced up new oil injectors and lines. Over 400 GBP, wow.