Loss of power & rattle, help!
04-28-2011, 10:15 AM
#51
Sydney, Australia
https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/mod-1-mizu-radiator-fans-mod-2-spal-fans-215539/
04-28-2011, 10:55 AM
#52
I got the coolant changed this morning. Car temps are definitely cooler now. I also noticed that when I go WOT and temps are around 83C or anywhere under 90C, that nasty raspy sound is NOT THERE. I will closely monitor. It does appear to be temperature related now. I am just below half a tank of gas. When its empty, I will run a can of BG44K through the gas tank and clean out the injectors to rule out that.
The tech also checked all exhaust heat shields and all shields underneath the car by the CAT and resonator, and all are tight, so it's not a shield rattle issue.
Tonight, I will diagnose the FAN FUSE, and jumper the FAN relays to see if they are even working. Aside from noise, where can I peek at to look to see the fans spin? I can't seem to find a way to look at them without extensively removing anything. I don't just want to "hear" the noise of the fan and assume its working right.
The tech also checked all exhaust heat shields and all shields underneath the car by the CAT and resonator, and all are tight, so it's not a shield rattle issue.
Tonight, I will diagnose the FAN FUSE, and jumper the FAN relays to see if they are even working. Aside from noise, where can I peek at to look to see the fans spin? I can't seem to find a way to look at them without extensively removing anything. I don't just want to "hear" the noise of the fan and assume its working right.
04-28-2011, 04:50 PM
#53
Okay, so in stop and go city driving, the temps are still between 92C and 98 C, and I when I gun it at WOT with those coolant temps, yes it still makes that nasty sound.
Can someone go WOT in their car in 2nd and 3rd gear past 4k when their coolant is above 92C and tell me whether you have these sounds or not?
All heatshields are tight, nothing loose.
Can someone go WOT in their car in 2nd and 3rd gear past 4k when their coolant is above 92C and tell me whether you have these sounds or not?
All heatshields are tight, nothing loose.
Last edited by Footman; 04-28-2011 at 04:56 PM.
04-28-2011, 08:13 PM
#57
Sydney, Australia
I got the coolant changed this morning. Car temps are definitely cooler now. I also noticed that when I go WOT and temps are around 83C or anywhere under 90C, that nasty raspy sound is NOT THERE. I will closely monitor. It does appear to be temperature related now. I am just below half a tank of gas. When its empty, I will run a can of BG44K through the gas tank and clean out the injectors to rule out that.
The tech also checked all exhaust heat shields and all shields underneath the car by the CAT and resonator, and all are tight, so it's not a shield rattle issue.
Tonight, I will diagnose the FAN FUSE, and jumper the FAN relays to see if they are even working. Aside from noise, where can I peek at to look to see the fans spin? I can't seem to find a way to look at them without extensively removing anything. I don't just want to "hear" the noise of the fan and assume its working right.
The tech also checked all exhaust heat shields and all shields underneath the car by the CAT and resonator, and all are tight, so it's not a shield rattle issue.
Tonight, I will diagnose the FAN FUSE, and jumper the FAN relays to see if they are even working. Aside from noise, where can I peek at to look to see the fans spin? I can't seem to find a way to look at them without extensively removing anything. I don't just want to "hear" the noise of the fan and assume its working right.
04-28-2011, 08:22 PM
#58
Sydney, Australia
"The car is back to running 'normally' for my setup (including the Masport thermo switch which cuts the fans in earlier) - temps are 85-95 celcuis - it just constantly moves within that range (185 - 203 Farenheit).
Its Autumn here (Fall) now so ambients are very mild, plus the car itself never had trouble in traffic - heat has only been an issue on track days and on long uphill climbs - and then only an 'issue' - never any symptoms of trouble apart from that one day mentioned in the original post.
Having said that I'm not expecting any trouble because of the speed that it moves from 95 back to 85 - it takes less than a minute to do this whether running or stopped so overall I think the solution is pretty healthy now."
04-28-2011, 10:09 PM
#59
OKay, I'm back from some diagnosing... I will be reviewing the electric circuitry afterwards, but before I do so, before I forget, I want to post some info here. I didn't bother removing airbox and battery tray, too much work for now. If need be and it gets bad, I'll do that.
In the relay box there are 3 relays, COOLING FAN 1, COOLING FAN 2, and COOLING FAN 3 (CF1, CF2, CF3 for simplicity from here on forward).
CF1 and CF2 are single pole relays
CF3 is also a single pole relay but has a front/back contact. In its default (coil not energized state), there is continuity between the common and the back contact. This is important because this connection allows the 12V to appear on the CF2 contacts. With CF3 relay removed, there is absolutely no way for any power to run the contacts through CF2. When I say this, I don't mean power through the coils.
So having the CF3 plugged in, I was able to jumper the contact on CF2 which has power now. CF2 turns on the fan on the passenger side. It will run it at approx 3A. Therefore 36 Watts.
Jumpering CF3's default contacts (common and back) do not have any voltage on them, it's a passthrough circuit allowing CF2's contact to have power. Jumpering CF3's common and front contact (simulating a coil pick up), the same fan on the passenger side turns on, but now runs at 4.8 A. Therefore 58 watts. I could physically hear it spin faster and there is a lot of wind coming through that side (beside the spaces around the coolant tank). Without seeing it spin, I could only assume it is working well.
CF1 does not have any voltage across the relays. I don't know what it does yet as I do not have enough jumpers with me to do the test. I suspect for now that if I pick up the coil on CF3 there would be voltage across the contacts on CF1.
Tomorrow I will get more jumpers and try to get CF1 going.
I also monitored the fan on-off cycle. WIth the car on idle and scangauge plugged in. The fan will turn on at 97 C (everyone knows this), but it will only stay on until the temps get to 94C and then shut off. This cycle repeats. When I turn the A/C on, "a fan" stays on indefinitely, I write that in quotes because I can't tell whether its the passenger side fan or the driver side fan.
If anyone has more info to contribute, please do so.
On a second note, I took it for a test drive this evening. Ambient temperatures are around 7 C. Driving with speed, the car easily maintains 80 - 81 C coolant temp. Coming to a stop, it slowly creeps up to 97 and as expected, the fan comes on, goes down to 94 C and then stops. Once I start driving again, the cool air cools down the radiator and temps start dropping back to 81 - 82C again. I went WOT several times in 1st, 2nd, 3rd when the temps were 92 - 96 C, and DID NOT hear the raspy sounds in the video clip that I used to get. This is puzzling me, all I did was flush/fill new coolant.
In the relay box there are 3 relays, COOLING FAN 1, COOLING FAN 2, and COOLING FAN 3 (CF1, CF2, CF3 for simplicity from here on forward).
CF1 and CF2 are single pole relays
CF3 is also a single pole relay but has a front/back contact. In its default (coil not energized state), there is continuity between the common and the back contact. This is important because this connection allows the 12V to appear on the CF2 contacts. With CF3 relay removed, there is absolutely no way for any power to run the contacts through CF2. When I say this, I don't mean power through the coils.
So having the CF3 plugged in, I was able to jumper the contact on CF2 which has power now. CF2 turns on the fan on the passenger side. It will run it at approx 3A. Therefore 36 Watts.
Jumpering CF3's default contacts (common and back) do not have any voltage on them, it's a passthrough circuit allowing CF2's contact to have power. Jumpering CF3's common and front contact (simulating a coil pick up), the same fan on the passenger side turns on, but now runs at 4.8 A. Therefore 58 watts. I could physically hear it spin faster and there is a lot of wind coming through that side (beside the spaces around the coolant tank). Without seeing it spin, I could only assume it is working well.
CF1 does not have any voltage across the relays. I don't know what it does yet as I do not have enough jumpers with me to do the test. I suspect for now that if I pick up the coil on CF3 there would be voltage across the contacts on CF1.
Tomorrow I will get more jumpers and try to get CF1 going.
I also monitored the fan on-off cycle. WIth the car on idle and scangauge plugged in. The fan will turn on at 97 C (everyone knows this), but it will only stay on until the temps get to 94C and then shut off. This cycle repeats. When I turn the A/C on, "a fan" stays on indefinitely, I write that in quotes because I can't tell whether its the passenger side fan or the driver side fan.
If anyone has more info to contribute, please do so.
On a second note, I took it for a test drive this evening. Ambient temperatures are around 7 C. Driving with speed, the car easily maintains 80 - 81 C coolant temp. Coming to a stop, it slowly creeps up to 97 and as expected, the fan comes on, goes down to 94 C and then stops. Once I start driving again, the cool air cools down the radiator and temps start dropping back to 81 - 82C again. I went WOT several times in 1st, 2nd, 3rd when the temps were 92 - 96 C, and DID NOT hear the raspy sounds in the video clip that I used to get. This is puzzling me, all I did was flush/fill new coolant.
04-28-2011, 10:22 PM
#60
According to Mazda tech manual,
Cooling fan No.1 Operating current should be between 8.9 - 11.9A
Cooling fan No.2 Operating current should be between 4.0 - 7.0A
So from the specs above, and the data I collected for CF2, it appears the CF2 fan is working properly. A fan that is hard to spin, has large resistance in spinning (from dirt or crap), will draw a larger current to achieve the same speed.
Cooling fan No.1 Operating current should be between 8.9 - 11.9A
Cooling fan No.2 Operating current should be between 4.0 - 7.0A
So from the specs above, and the data I collected for CF2, it appears the CF2 fan is working properly. A fan that is hard to spin, has large resistance in spinning (from dirt or crap), will draw a larger current to achieve the same speed.
04-28-2011, 11:00 PM
#61
I am stumped. I've found the diagnostic page from my tech manual showing the circuit. I can explain everything that I'm seeing except for the fact that, how does cooling fan 2 even get its 12V source and allow the fan to turn at 3A when the contacts are jumpered.
Darkbrew, I know you've got some electronic background, take a look, am I just too blurry eyed and tired to see the obvious?
Assuming CF3 relay is plugged in its de-energized normal state. If I jumped CF2 contacts, the diagram suggests the fan motor is going to get negative/negative on the terminals. Where is it getting the positive from?
Uploaded with ImageShack.us
Darkbrew, I know you've got some electronic background, take a look, am I just too blurry eyed and tired to see the obvious?
Assuming CF3 relay is plugged in its de-energized normal state. If I jumped CF2 contacts, the diagram suggests the fan motor is going to get negative/negative on the terminals. Where is it getting the positive from?
Uploaded with ImageShack.us
04-28-2011, 11:33 PM
#62
Sydney, Australia
Just to reiterate - you don't need to remove the battery to get to the main cooling fan - just the airbox and the tray underneath that that holds the airbox. The tests you ahve done seem to be getting to the same concluions though, albeit in a complicated manner.
re this: "I also monitored the fan on-off cycle. WIth the car on idle and scangauge plugged in. The fan will turn on at 97 C (everyone knows this), but it will only stay on until the temps get to 94C and then shut off. This cycle repeats. When I turn the A/C on, "a fan" stays on indefinitely, I write that in quotes because I can't tell whether its the passenger side fan or the driver side fan."
with the AC on both fans should be spinning - I believe that is the normal situation.
re this: "I also monitored the fan on-off cycle. WIth the car on idle and scangauge plugged in. The fan will turn on at 97 C (everyone knows this), but it will only stay on until the temps get to 94C and then shut off. This cycle repeats. When I turn the A/C on, "a fan" stays on indefinitely, I write that in quotes because I can't tell whether its the passenger side fan or the driver side fan."
with the AC on both fans should be spinning - I believe that is the normal situation.
04-29-2011, 08:31 AM
#63
Extraordinary Engineering
I am stumped. I've found the diagnostic page from my tech manual showing the circuit. I can explain everything that I'm seeing except for the fact that, how does cooling fan 2 even get its 12V source and allow the fan to turn at 3A when the contacts are jumpered.
Darkbrew, I know you've got some electronic background, take a look, am I just too blurry eyed and tired to see the obvious?
Assuming CF3 relay is plugged in its de-energized normal state. If I jumped CF2 contacts, the diagram suggests the fan motor is going to get negative/negative on the terminals. Where is it getting the positive from?
Darkbrew, I know you've got some electronic background, take a look, am I just too blurry eyed and tired to see the obvious?
Assuming CF3 relay is plugged in its de-energized normal state. If I jumped CF2 contacts, the diagram suggests the fan motor is going to get negative/negative on the terminals. Where is it getting the positive from?
In Blue is both fans running on 12V
Last edited by DarkBrew; 04-29-2011 at 08:38 AM.
04-29-2011, 09:52 AM
#66
Extraordinary Engineering
How sure are you of the designations?
There are three possibilities that come to mind.
1) You are not shorting what you think you're shorting... for example, shorting the control signal of relay 2 to ground will activate relay 3 and turn on the fan
2) There is some unintended current path you'll have to track down.
3) The PCM is reacting to the loss of the relay coil resistance and changing some settings??
Last edited by DarkBrew; 04-29-2011 at 09:59 AM.
04-29-2011, 10:07 AM
#67
unintended current of 3A going to ground is pretty bad I'd say...
I am very sure. If you remove the relay and look at the back. The silver contacts are the coils, and the copper contacts are the power paths.
I tested each relay individually applying 12V across the coils, they all click. With a second meter I did a continuity test to ensure that the power pathes do indeed conduct after the coil has been picked up.
I am very sure. If you remove the relay and look at the back. The silver contacts are the coils, and the copper contacts are the power paths.
I tested each relay individually applying 12V across the coils, they all click. With a second meter I did a continuity test to ensure that the power pathes do indeed conduct after the coil has been picked up.
04-29-2011, 10:51 AM
#71
Extraordinary Engineering
05-02-2011, 07:26 AM
#74
This is in direct reference to those suffering with the noise that appears in various videos in this thread.
Here's everything I've tried that is NOT the cause for me:
a) cracked exhaust rattle (I welded it up and everything, not the cause)
b) heat shields underneath the exhaust, silencer, CAT
c) loose sparkplug wires
d) lower grade fuel (I use VPower 91)
I'm at 85,000km on original coolant and I've noticed the car was running rather hot. I had been monitoring temps for awhile. I've verified all fans are working right, and there are no coolant leaks underneath the car. No white smoke either (so it's not cracked housings).
In the timeline of things, here is what I did to fix so far. I did a complete flush and fill with OEM FL-22 coolant. The car was running cooler, and the noise in the video was reduced. Having the coolant changed which also implicitly meant the cooling system was burped of air bubbles, the MIAC sand in blender sound coming from the glove box also was significantly reduced, it's barely audible now.
I did not install the orifice
Since the coolant flush, I have poured in one can of BG44K into the gas tank. I am down to 3/10 tank left currently as of writing, and since pouring BG44K into the tank, I have never heard those noises ever again in high rpms at WOT in any gear.
If BG44K indeed this solve the problem, then that means the noise is caused by carbon build up somewhere.. in the apex seals, in the intake ports, in the fuel injectors.. etc.. the chattering noise could be fuel sputter from dirty injectors not suppling enough fuel (thus having noticable reduction in power), or chattering of the apex seals (skipping), not providing sufficient sealing, thus the combustiion cycles are overlapping slightly. All contribute to reduced fuel economy and power.
This is odd because I redline frequently. The car is daily driver. I use V-power 91 only, and would imply that carbon buildup is still significant!
I will continue to monitor and report back.
Here's everything I've tried that is NOT the cause for me:
a) cracked exhaust rattle (I welded it up and everything, not the cause)
b) heat shields underneath the exhaust, silencer, CAT
c) loose sparkplug wires
d) lower grade fuel (I use VPower 91)
I'm at 85,000km on original coolant and I've noticed the car was running rather hot. I had been monitoring temps for awhile. I've verified all fans are working right, and there are no coolant leaks underneath the car. No white smoke either (so it's not cracked housings).
In the timeline of things, here is what I did to fix so far. I did a complete flush and fill with OEM FL-22 coolant. The car was running cooler, and the noise in the video was reduced. Having the coolant changed which also implicitly meant the cooling system was burped of air bubbles, the MIAC sand in blender sound coming from the glove box also was significantly reduced, it's barely audible now.
I did not install the orifice
Since the coolant flush, I have poured in one can of BG44K into the gas tank. I am down to 3/10 tank left currently as of writing, and since pouring BG44K into the tank, I have never heard those noises ever again in high rpms at WOT in any gear.
If BG44K indeed this solve the problem, then that means the noise is caused by carbon build up somewhere.. in the apex seals, in the intake ports, in the fuel injectors.. etc.. the chattering noise could be fuel sputter from dirty injectors not suppling enough fuel (thus having noticable reduction in power), or chattering of the apex seals (skipping), not providing sufficient sealing, thus the combustiion cycles are overlapping slightly. All contribute to reduced fuel economy and power.
This is odd because I redline frequently. The car is daily driver. I use V-power 91 only, and would imply that carbon buildup is still significant!
I will continue to monitor and report back.
05-09-2011, 03:23 PM
#75
Okay, the noise came back again, it happened during a track session. Not an autocross session where there might not be enough air going into the radiator. My coolant temps were good throughout, but it was making that noise again at the higher RPM. It seemed to struggle going to redline. No CEL, nothing.
My fuel economy is still good though, still better than before even with track session.
I didn't look underneath the car to look for any glowing CATs. It seems to be intermittent now, I sometimes get it, I sometimes don't. They all seem to happen after prolonged driving, or extensive heat.
Anyone have more ideas? BG44k helped reclaim some power/fuel economy, but did not entirely remove this problem. It's just like the videos in this thread.
My fuel economy is still good though, still better than before even with track session.
I didn't look underneath the car to look for any glowing CATs. It seems to be intermittent now, I sometimes get it, I sometimes don't. They all seem to happen after prolonged driving, or extensive heat.
Anyone have more ideas? BG44k helped reclaim some power/fuel economy, but did not entirely remove this problem. It's just like the videos in this thread.