LOW on POWER
01-22-2008, 01:55 PM
#1
Asleep at the wheel
Thread Starter
LOW on POWER
Hi guys
Had my 2003 stock std rx8 on my own dyno this weekend.
My car was feeling low on power since I bought it in Nov 2007.
So I started browsing the net and this Forum for any info.
So far the only thing that might make sense is coils.
The car has 86000 km on the clock and in very good condition.
I'm the second owner and the car's got full service history. (contact the mazda service deparment).
Mazda says there is nothing wrong with my car and there is also no fault codes.
Did a ECU reset and had a small improvement in midrange.
It's a 6 speed. The dyno is a Dastek dyno. On enertia run the car made a little less hp.
When driving the car it feels as if it struggles to get some air into the motor from 6000 rpm upwards.
I checked at the engine that the SSV actuator and the VDI actuator opens at WOT on the dyno.
Could not check the APV motor for operation. I do not think that the APV itself would make such a big diff.
So all I got out the car was 97rwkw(131.08 rwhp) while braking the dyno at 8200 rpm.(3rd gear and also 4th)
Checked the AF ratio's :
Idle - 15.2
Mid - 13.8
WOT - 12.8
I made about 6 runs to verify.
Any ideas.
Had my 2003 stock std rx8 on my own dyno this weekend.
My car was feeling low on power since I bought it in Nov 2007.
So I started browsing the net and this Forum for any info.
So far the only thing that might make sense is coils.
The car has 86000 km on the clock and in very good condition.
I'm the second owner and the car's got full service history. (contact the mazda service deparment).
Mazda says there is nothing wrong with my car and there is also no fault codes.
Did a ECU reset and had a small improvement in midrange.
It's a 6 speed. The dyno is a Dastek dyno. On enertia run the car made a little less hp.
When driving the car it feels as if it struggles to get some air into the motor from 6000 rpm upwards.
I checked at the engine that the SSV actuator and the VDI actuator opens at WOT on the dyno.
Could not check the APV motor for operation. I do not think that the APV itself would make such a big diff.
So all I got out the car was 97rwkw(131.08 rwhp) while braking the dyno at 8200 rpm.(3rd gear and also 4th)
Checked the AF ratio's :
Idle - 15.2
Mid - 13.8
WOT - 12.8
I made about 6 runs to verify.
Any ideas.
01-22-2008, 02:07 PM
#4
Asleep at the wheel
Thread Starter
I didn't print the graph but i did check it with other graphs from the forum and my car does not have the dips in the graph. Although the actuators did operate each on its own as the revs went up to 8500. Could also hear the engine tone change.
Will do another few runs this weekend and save the graph.
Will do another few runs this weekend and save the graph.
08-20-2010, 09:12 AM
#5
Extraordinary Engineering
Low Power issue
Here's the issue I've been fighting
Summary:
2004 6MT: Build date March 2004: 125,000 km: Starts well, Runs well, smooth idle, average MPG, no CEL, normal oil consumption, All recalls done
Low HP on Dyno day. MM said that the MAF max flow was low.
Charted MAF readings against a healthy RX-8: the flow diverges over 6000 RPM
Pulled Cat - no difference
Cleaned MAF, TB and changed air filter. Checked TB operation. - no difference
Vacuum tested the VDI and SSV actuators - working - linkages move freely.
Removed VFAD crap after finding a vacuum leak. - no difference (VFAD was jammed open)
Seafoamed - no difference
Verified APV motor working (self test).
We ran the engine RPMs up to 6K with no observed movement of SSV actuator... Does this need load to operate?
Supposition
The AFR stays rich so we do not suspect the fuel pump
Starting and idle are very good so we think compression is good
Not verified
Air solenoids under UIM for SSV, VDI
UIM internals (VDI, SSV)
LIM internals (APVs)
Summary:
2004 6MT: Build date March 2004: 125,000 km: Starts well, Runs well, smooth idle, average MPG, no CEL, normal oil consumption, All recalls done
Low HP on Dyno day. MM said that the MAF max flow was low.
Charted MAF readings against a healthy RX-8: the flow diverges over 6000 RPM
Pulled Cat - no difference
Cleaned MAF, TB and changed air filter. Checked TB operation. - no difference
Vacuum tested the VDI and SSV actuators - working - linkages move freely.
Removed VFAD crap after finding a vacuum leak. - no difference (VFAD was jammed open)
Seafoamed - no difference
Verified APV motor working (self test).
We ran the engine RPMs up to 6K with no observed movement of SSV actuator... Does this need load to operate?
Supposition
The AFR stays rich so we do not suspect the fuel pump
Starting and idle are very good so we think compression is good
Not verified
Air solenoids under UIM for SSV, VDI
UIM internals (VDI, SSV)
LIM internals (APVs)
Last edited by DarkBrew; 08-20-2010 at 09:16 AM.
08-20-2010, 09:34 AM
#6
The devil made me do it
iTrader: (1)
Join Date: Jul 2007
Location: Colorado Springs, CO
Posts: 3,708
Likes: 0
Received 2 Likes
on
2 Posts
Rotorbug - Along the lines of where DarkBrew was thinking check your VFAD for a leak. Easiest way to do that would be to remove the VFAD hose and cap it off and see if the issue goes away. Other then that I would be going with nycgps and thinking plugs or coils.
DarkBrew - When we were working on Vyn's SSV a while back we saw the same thing with the SSV. The car needs to be in gear for it to open for some reason. However, if you take a pump you can get the SSV to move and as long as it moves freely it should open under load. You should also feel the point when it opens as your torque jumps.
DarkBrew - When we were working on Vyn's SSV a while back we saw the same thing with the SSV. The car needs to be in gear for it to open for some reason. However, if you take a pump you can get the SSV to move and as long as it moves freely it should open under load. You should also feel the point when it opens as your torque jumps.
Last edited by DeViLbOi; 08-20-2010 at 09:43 AM.
08-20-2010, 09:57 AM
#7
Extraordinary Engineering
Rotorbug - Along the lines of where DarkBrew was thinking check your VFAD for a leak. Easiest way to do that would be to remove the VFAD hose and cap it off and see if the issue goes away. Other then that I would be going with nycgps and thinking plugs or coils.
DarkBrew - When we were working on Vyn's SSV a while back we saw the same thing with the SSV. The car needs to be in gear for it to open for some reason. However, if you take a pump you can get the SSV to move and as long as it moves freely it should open under load. You should also feel the point when it opens as your torque jumps.
DarkBrew - When we were working on Vyn's SSV a while back we saw the same thing with the SSV. The car needs to be in gear for it to open for some reason. However, if you take a pump you can get the SSV to move and as long as it moves freely it should open under load. You should also feel the point when it opens as your torque jumps.
There is activity but I wouldn't say torque jumps...
08-23-2010, 12:58 AM
#9
Asleep at the wheel
Thread Starter
Dead RX8
Well I eventually found the problem with my car.
It's called : Mazda made a boo boo!
Bad boys! The Renesis in my car went bey bey.
No 2 rotor apex seal broke and destroyed the rest. This was in morning traffic!
See the replacement here:https://www.rx8club.com/series-i-major-horsepower-upgrades-93/series-5-rx7-turbo-into-rx8-197699/
It's called : Mazda made a boo boo!
Bad boys! The Renesis in my car went bey bey.
No 2 rotor apex seal broke and destroyed the rest. This was in morning traffic!
See the replacement here:https://www.rx8club.com/series-i-major-horsepower-upgrades-93/series-5-rx7-turbo-into-rx8-197699/
10-04-2010, 09:08 AM
#10
Extraordinary Engineering
Air solenoids under UIM for SSV, VDI
UIM internals (VDI, SSV)
LIM internals (APVs)
UIM internals (VDI, SSV)
LIM internals (APVs)
After systematically checking everything on the list I narrowed it down to a small vacuum leak on the SSV actuator. It drained to half vacuum on the gauge in 5 seconds.
I sourced a working SSV actuator and recently installed it.
On the AP data chart you can see the before and after air flow reading.
Thread
Thread Starter
Forum
Replies
Last Post
