Notices
Series I Tech Garage The place to discuss anything technical about the RX-8 that doesn't fit into any of the categories below.

Power Drops @ 7-8K

Old May 15, 2004 | 03:33 AM
  #1  
6mm's Avatar
6mm
Thread Starter
Registered
 
Joined: Mar 2004
Posts: 106
Likes: 0
From: Alaska
Power Drops @ 7-8K

After the latest ECU update I have noticed a new and disturbing power loss under certain acceleration.

To set the scenario, here is exactly how I have experienced and can consistently reproduce the issue:

At speed in 4th or 5th gear (approximately 60MPH)
Downshift to 3rd and accelerate at full throttle
Power comes on smoothly through the 6-7K RPM range
Somewhere after 7K a series of what feels like loss of fuel "bumps" or erratic "burbles" where the acceleration slows and drops off dramatically
Once past 8K the smoothness returns and comes on for the last 1K

Anyone else experience this sort of thing?

Note: I did not hear any detonation or strange sounds...but it is so obvious that the first time I felt while romping along with stereo UP and windows DOWN - immediately prompting the closed windows and close listening!

Thoughts?
Reply
Old May 15, 2004 | 09:12 AM
  #2  
rotaryDemon's Avatar
Registered User
 
Joined: Oct 2003
Posts: 98
Likes: 0
same here. did you mod/replace your intake?
Reply
Old May 15, 2004 | 10:54 AM
  #3  
wakeech's Avatar
mostly harmless
 
Joined: Jun 2002
Posts: 3,440
Likes: 0
From: Greater Vancouver Area, BC
how about your spark plugs?? have you had a tune up lately?? could be a misfire.
Reply
Old May 15, 2004 | 11:52 AM
  #4  
6mm's Avatar
6mm
Thread Starter
Registered
 
Joined: Mar 2004
Posts: 106
Likes: 0
From: Alaska
1400 miles = needs a tune up? :|

no mods to the intake at this time - all stock
Reply
Old May 15, 2004 | 02:00 PM
  #5  
snap-on's Avatar
Registered User
 
Joined: Mar 2004
Posts: 1,050
Likes: 0
We need a Poll on this issue.

It would be nice to see if this happens right away or after a few miles?

Also if a PCM reset makes the problem go away for a while?

This is not the first time this problem has been noticed.

It certainly will not be the last..

Last edited by snap-on; May 15, 2004 at 03:36 PM.
Reply
Old May 15, 2004 | 07:31 PM
  #6  
TheDosDog's Avatar
Recovered Modaholic
 
Joined: Dec 2003
Posts: 496
Likes: 2
From: Napa, Ca.
I had a hesitation at 7-9k. Just felt kind of flat. Then it started throwing CELs. Turned out to be bad coils. I had them replaced last week (warranty) and now its running good as/better than new.
Reply
Old May 15, 2004 | 07:57 PM
  #7  
x28's Avatar
x28
Registered User
 
Joined: Sep 2003
Posts: 133
Likes: 0
I noticed the same problem and I hvae the canzoomer 1.1
Reply
Old May 15, 2004 | 09:04 PM
  #8  
rudy8's Avatar
Registered User
 
Joined: Feb 2004
Posts: 295
Likes: 0
From: michigan
I have canzoomer 1.1 and RE intake with M flash.
feels stronger after 7 K .
in fact, i was out tonight in those rpm range and noticed how nice it was.
Reply
Old May 16, 2004 | 09:07 AM
  #9  
olddragger's Avatar
Registered
iTrader: (3)
 
Joined: Apr 2004
Posts: 10,828
Likes: 40
From: macon, georgia
Guys,
I have the cz1.1, the L flash and rb catback. I think I was kind of spoiled with the Pre L flash's in which you could "feel the kick" at about 6-7k. There is more under the curve power now but I also agree that at about 7500 or so the power either flattens out or maybe actually drops just a little. Think maybe I have some bad coils? Engine is smooth otherwise. There is a differance with the dsc off but only a little. I had the L flash and added the catback and cz at the same time.
olddragger
Reply
Old May 16, 2004 | 11:13 AM
  #10  
TheDosDog's Avatar
Recovered Modaholic
 
Joined: Dec 2003
Posts: 496
Likes: 2
From: Napa, Ca.
I don't have a CZ and I doubt my issue was related to my "M" flash update. More the reason they applied the "M" in the first place. The defect in the coils was only apparent at high revs. Otherwise the motor ran great. If it hadn't thrown the CEL I probably would not have taken it in. It felt dead opposite of when the car was new. Fast accell to 7k then went flat, almost dragging to redline. Now with "M" and new coils the powerband is pretty even all the way up. The mechanic was able to diagnose the problem through visual inspection of the coils. I found another thread with pics that shows this pretty clearly.

https://www.rx8club.com/showthread.p...highlight=coil
Reply
Old May 16, 2004 | 04:59 PM
  #11  
zoom44's Avatar
Administrator
 
Joined: Jul 2002
Posts: 21,958
Likes: 115
From: portland oregon
haven't noticed this in my car yet. have not reset the pcm.
Reply
Old May 30, 2004 | 07:48 PM
  #12  
RX8_Denis's Avatar
Registered User
 
Joined: Apr 2004
Posts: 5
Likes: 0
From: Moncton, NB, Canada
I had somethin similar happen to me when car engine was still cold.... but rather at around 5k rpm... in 1st.... then shifted to second and again at 5k... I felt a flat spot... not sure what to make of it
Reply
Old May 30, 2004 | 08:04 PM
  #13  
guy321's Avatar
Humpin legs and takin nam
 
Joined: Nov 2003
Posts: 2,433
Likes: 0
From: Clearwater, Fl
just got my M flash.. and don't notice that problem with my CZ on or off. I did just get new plugs when getting my flash too..

I will keep an eye out for it.. but I have been running the car hard to heat it up so I can get under the exhaust to track down a rattle.. So I think I would have noticed since I've been listening and driving hard.

I think that RX8friend said that M flash does some wierd stuff above 7k RPM's tho..
Reply
Old Jun 2, 2004 | 08:50 AM
  #14  
Velocity-8's Avatar
Whuumpha!!
 
Joined: Jan 2004
Posts: 512
Likes: 0
From: New Jersey
I have the M flash and the RX8Store exhaust. My 8 has a very noticable power drop at 6K when downshifting and accelerating. The power drops for about 400 rpm then is kicks back on.

My CZ1 is on it's way so I'll see if that gets rid of the power loss.
Reply
Old Jun 6, 2004 | 12:53 PM
  #15  
LewNutz's Avatar
Registered User
 
Joined: May 2004
Posts: 35
Likes: 0
From: Atlanta, GA
Originally posted by RX8_Denis
I had somethin similar happen to me when car engine was still cold.... but rather at around 5k rpm... in 1st.... then shifted to second and again at 5k... I felt a flat spot... not sure what to make of it
This might explain your problem.

Page 5-4 of the Manual (US Version) in the Note box:

"To protect the engine, when the engine coolant tempurature is low, the engine does not run at high speeds. The fuel supply will be cut at an rpm lower than the red zone."
Reply
Old Jun 25, 2004 | 11:51 PM
  #16  
gr8rx8's Avatar
Registered User
 
Joined: May 2004
Posts: 8
Likes: 0
From: Tucson, Arizona
I've noticed similar behavior a couple of times when accelerating in 4th: at about 6500-7000 rpm, the engine starts making "knocking" noises and starts losing power. Mazda has evidently noticed it, too. A new PCM reflash called "MSP04" addresses this problem. It was released on 6-2-04, and describes this problem almost exactly. This bulletin is listed on the Rosenthal Mazda website:

http://www.finishlineperformance.co.../01-022-04.html

(The site home is: http://www.finishlineperformance.com/rx8/index.html)

Three weeks ago, I took my car in to get this problem diagnosed because it was starting to worry me. The mechanic drove my car 25 miles and couldn't duplicate the problem. Afterwards, he flashed the PCM with the new MSP04 as part of the dealership's standard procedure to perform the latest reflashes and recalls when a customer brings a car in for service. When I picked up the car, the advisor said, " Our tech couldn't isolate the problem," so I drove home thinking the problem might still be there. When I got home, I researched the MSP04 they had performed, and realized they had fixed the problem without even knowing it! Anyway, my 8 is running fine now, the problem has not reappeared, and I've even detected a bit more mid-range torque.
Reply
Old Jun 26, 2004 | 01:17 AM
  #17  
zoomed's Avatar
Registered User
 
Joined: Mar 2004
Posts: 52
Likes: 0
From: Bakersfield, CA
You know, on most cars that either have a cam shift or secondary intake kick in at high rpm, you get this satisfying rush of power. I think I was on K and now on L, and in both cases, you can feel the secondary ports open around 7k and you get a little more power, but it isnt that great, and fairly uneven. I blame it on emissions tuning. But it is my primary disappointment with the engine.
Reply
Old Jul 16, 2004 | 03:28 PM
  #18  
Maolin34's Avatar
Registered User
 
Joined: Jul 2004
Posts: 92
Likes: 0
I agree with the power drop. I had the M flash two days ago. Before the reflash I had a noticeable bump at the 6250rpm intake opening....now it is just smooth power until I hit 6500-7000, and it simply goes flat....then comes back in at about 7500-8000....I am very disappointed. Also, if someone has really bad gas mileage, let me know!!! I am averaging 12-13 mpg. HELP!
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
RevMeHarder
New Member Forum
8
Jun 1, 2026 02:30 PM
JimmyBlack
Series I Major Horsepower Upgrades
273
Feb 10, 2020 10:23 PM
TeslaMSI
New Member Forum
11
Dec 10, 2015 01:10 AM
juicemantwon
New Member Forum
3
Sep 26, 2015 12:30 PM


Thread Tools
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -5. The time now is 12:01 PM.