Notices
Series I Trouble Shooting This is the place to learn more about or discuss any issues you're having with your RX-8

Power Loss after engine heats up

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old 10-08-2010, 06:12 AM
  #1  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Angry Power Loss after engine heats up

Hi All. Some time ago my car started to loose power after driving for around 15 mins. Have to downshift to as low as 2nd gear to get it moving.
Got a CEL few days later: dead ignition coil. Changed those together with spark plugs but still same ****. Another thing is that it won't restart when i shut down if the engine is hot, i.e has been running for more than 15 mins. If it is cold then no prob in multiple starts.
Any ideas most welcome. Checked the other threads on the issue but haven't found anything conclusive. please help.

Thanks. Rud
2004, 5spd MT, stock.
Old 10-08-2010, 06:46 AM
  #2  
FULLY SEMI AUTOMATIC
iTrader: (9)
 
200.mph's Avatar
 
Join Date: Aug 2008
Location: BALLS DEEP
Posts: 5,649
Received 2,386 Likes on 2,014 Posts
mileage? cat? compression check
Old 10-08-2010, 10:53 AM
  #3  
Administrator
iTrader: (7)
 
Jedi54's Avatar
 
Join Date: Mar 2004
Location: The Dark Side
Posts: 22,411
Received 2,718 Likes on 1,959 Posts
^^^ what he said.

have you checked the cat? It could be clogged
Old 10-08-2010, 11:37 PM
  #4  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Hi. Mileage:90k km, around 56k miles. I'll check the cat. One question though, it seems that the previous owner used the wrong type of spark plug (what i heard from a friend who knows the previous owner well). Is it possible, by the symptoms, that i may have a broken apex seal? I was thinking of getting an engine kit from Atkins and redo all the seals. What do you guys think? is it worth?
Old 10-08-2010, 11:41 PM
  #5  
Registered
 
Bluerenesis's Avatar
 
Join Date: Aug 2010
Location: Boise, Idaho
Posts: 300
Likes: 0
Received 1 Like on 1 Post
Originally Posted by rud
Hi. Mileage:90k km, around 56k miles. I'll check the cat. One question though, it seems that the previous owner used the wrong type of spark plug (what i heard from a friend who knows the previous owner well). Is it possible, by the symptoms, that i may have a broken apex seal? I was thinking of getting an engine kit from Atkins and redo all the seals. What do you guys think? is it worth?
I wouldnt go to that extreme yet until you cross off all the easy possible fixes but I really think you should get the compression tested after checking the CAT like the others stated.
Old 10-09-2010, 10:44 AM
  #6  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
I've got the 9B like all of you but the 8C instead of 7C which is most common in the states. I got mine from the UK, made NGK. Interesting enough, while changing the spark plugs i found out that the rear rotor plugs were inverted. I put all plugs back to "normal" and that's when I flooded the engine.
I just took the car on the motorway and drove it like hell and it did satisfy me. It is running super fine for the first 15-20km. Pulled over, put the engine off. Checked the CAT, nothing glowing. But the damned thing won't restart. Waited 10 mins and it started again like everything's normal and drove just fine...
Can't find a rotary compression tester on island with only 2 dozens 8s and a coulple of 7s. Will try to get a "normal" compression test on Monday.
Coils are from the UK, OEM part. Suppression wires from B&B in the states.
Cheers from Mauritius.

Rud
Old 10-09-2010, 02:23 PM
  #7  
Registered
 
Bluerenesis's Avatar
 
Join Date: Aug 2010
Location: Boise, Idaho
Posts: 300
Likes: 0
Received 1 Like on 1 Post
Is your car stock or does it have any performance modifications?
Let us know Monday about your compression results and any ideas the mechanics have.
Old 10-10-2010, 01:35 AM
  #8  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Yes, will post the results tomorrow. The car is bone stock, no mods whatsoever. Another new thing i witnessed: It had a sudden surge in power around 6k rpm on first gear, it was quite brutal, not smooth, never had that before. 2nd gear was ok up to 8k rpm and so was 3rd.
Old 10-12-2010, 01:12 AM
  #9  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Hi all. Couldn't do the compression test yesterday, the bugger wouldn't start again!!! She flooded again. By the time I got her started, all garages were closed.
Can someone please explain to me why she wouldn't start when hot but when I push-start her, she starts just fine. Battery is fine, alternator is fine, starter is good, new coils, new spark plugs!!! I just can't find a logical explanation.
To de-flood it, i removed my plugs and unplugged the coils and removed the fuel fuse and turned the engine on starter to evacuate the gas. Something i noticed is that the gas came out with more pressure from the rear rotor than the front. Is it normal?
It's really getting me on my nerves, have to borrow my mum's old Civic to go to work...
Old 10-12-2010, 02:29 PM
  #10  
Grasshopper
iTrader: (1)
 
Jon316G's Avatar
 
Join Date: Dec 2006
Location: Streetsboro, OH
Posts: 6,779
Likes: 0
Received 46 Likes on 33 Posts
Originally Posted by Charles R. Hill
No.

Compression test.
Compression test.
Compression test.
Agree.
Not sure why people lately are ignoring this advise when given.
Guess they like to waste money and time on other unlikely components.
Old 10-13-2010, 05:41 AM
  #11  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Jon316G
Agree.
Not sure why people lately are ignoring this advise when given.
Guess they like to waste money and time on other unlikely components.
Hi Jon, I'm not ignoring your advice, on the contrary. I'm from a small country lost in the middle of the indian ocean, and on top of that I work 12-14 hours a day...not an easy life i assure you, my two year old son will tell you something about it...

Good news, i got someone to do the test for me as I am "too busy". Reported results: Front Rotor 100-102 psi, rear rotor 106-108 psi.

He also got an Air Flow Sensor malfunction (IAF?), which did not generate any CEL. He says there is an overvoltage when the engine is hot and it closes the air supply when i try to start the engine. He will do some more tests by tomorrow.

Charles, Jon and all you guys, I really appreciate your help and advice and I'm very grateful. Please let me know what you think about the results. He will do another compression test maybe tomorrow.

Thanks.
Old 10-13-2010, 05:51 AM
  #12  
Grasshopper
iTrader: (1)
 
Jon316G's Avatar
 
Join Date: Dec 2006
Location: Streetsboro, OH
Posts: 6,779
Likes: 0
Received 46 Likes on 33 Posts
Originally Posted by rud
Good news, i got someone to do the test for me as I am "too busy". Reported results: Front Rotor 100-102 psi, rear rotor 106-108 psi.
We need to see the compression numbers of all three rotor facings, per rotor, and at what RPM.

Originally Posted by rud
He also got an Air Flow Sensor malfunction (IAF?), which did not generate any CEL. He says there is an overvoltage when the engine is hot and it closes the air supply when i try to start the engine. He will do some more tests by tomorrow.
What was the voltage reading on the MAF at idle?
There is no way to close the air supply since the primary intake runners don't have valves.
Only the throttle body could "close" air supply... and even that stays open at 5 degrees and is easily visible to verify when the flexible tube is removed.
Old 10-13-2010, 06:15 AM
  #13  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Damn, I really don't know if there is a rotary compression gauge on the island... All 8s in Mauritius are second hand imports from Japan, our local dealer does not do 8s, and with only around 15-20 rotaries here...tough job.
Ok for the MAF voltage, i'll ask for those.
Do you have any idea why it starts fine when i push start it???
I did check the throttle a few days ago, curious but i did not notice the 5 degree opening, will check that again.
Regarding the compression test, I don't know how accurate his instrument is. But when i tried to de-flood the engine there were the three distinct "Phsst" from both rotors.
Old 10-13-2010, 06:30 AM
  #14  
Grasshopper
iTrader: (1)
 
Jon316G's Avatar
 
Join Date: Dec 2006
Location: Streetsboro, OH
Posts: 6,779
Likes: 0
Received 46 Likes on 33 Posts
Originally Posted by rud
Do you have any idea why it starts fine when i push start it???
Could be a combination of battery and starter.
Many people misunderstand the problem with these components and say, "I'll just get them tested."
Thing is, they will test OK because there is nothing wrong with them alone.
The original battery did not supply enough crank amps and the starter wasn't delivering enough torque consistently.
I myself had issues where it would start fine cold, but then had trouble starting when it was warmed.
New battery and starter solved that for me (and my compression is still good).

Originally Posted by rud
I did check the throttle a few days ago, curious but i did not notice the 5 degree opening, will check that again.
Its easier to just observe the valve while someone is in the car pressing the gas pedal.
No need to start the car, just turn the key to 'ON'.
The valve remains slightly open at rest in case throttle control signals are lost and the PCM enters a fail-safe mode.
This position provides a high idle speed to allow the car to be driven.

Originally Posted by rud
Regarding the compression test, I don't know how accurate his instrument is. But when i tried to de-flood the engine there were the three distinct "Phsst" from both rotors.
If you can hear the three "Phsst" sounds from both rotors, you may be fine (or enough to at least run the engine).
If the sound is consistent and doesn't appear to "skip" or miss a sound, that's a good sign.
We were concerned with the comment about gas coming out with more pressure.
Usually if its that noticeable, then there is a noticeable compression difference between the two rotors.
Old 10-14-2010, 03:01 AM
  #15  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Hi Guys. I was really sceptic yesterday when the garage called me to give the compression test results, and rightly so. Was just there this morning and redid the test, twice.
All of you guys were right, i got a 1:4 ratio on both rotors instead of the rated 1:10.

Well atleast now i know where the trouble comes from, even if that means spending some more money...
Old 10-15-2010, 08:02 AM
  #16  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
No comments from anybody... : (
Checked the compression again today with another manometer, the hand hardly moves during compression, nothing really to do with the sensitivity of the instrument, needle went up on my Civic, but moves very little on the 8... I definitely need some courage to tackle this one, guess my car will have to stay in the garage for quite some time, till i get parts flying from the states...
Old 01-18-2011, 06:37 AM
  #17  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Hey Guys, I'm back. Just got the engine back to where it should be yesterday, fired it up today.
Had a broken apex seal and a broken side seal in my rear rotor! Plus oil scraper rings were fully worn out. Anyway, got everything new in that engine and hope it will last some time.
I will road test the car tomorrow but i have one important question: What is the Break-In period for a rebuilt rotary?
Your comments and advice will be most appreciated.
Cheers.
Rud
Old 01-18-2011, 06:47 AM
  #18  
Registered
 
EricMeyer's Avatar
 
Join Date: Oct 2007
Location: Indianapolis, IN
Posts: 684
Likes: 0
Received 13 Likes on 12 Posts
Originally Posted by rud
Hey Guys, I'm back. Just got the engine back to where it should be yesterday, fired it up today.
Had a broken apex seal and a broken side seal in my rear rotor! Plus oil scraper rings were fully worn out. Anyway, got everything new in that engine and hope it will last some time.
I will road test the car tomorrow but i have one important question: What is the Break-In period for a rebuilt rotary?
Your comments and advice will be most appreciated.
Cheers.
Rud
The break-in period revolves around new and used bearings. Same for seals. Quite honestly we warm up the car for 30 minutes idle. We then spend an hour at about 2,000 rpm and then drive the heck out of it.
Old 01-19-2011, 08:05 AM
  #19  
rud
Registered User
Thread Starter
 
rud's Avatar
 
Join Date: Jan 2010
Location: Mauritius
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Hey Eric. Thanks for the advice. Tried the car today, had a 80 km ride, not a single hot stop/start problem. Power was consistent all over.
I think it was well worth the wait and money. I just hope it lasts...
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Audio Concepts ATL
New Member Forum
21
09-26-2021 01:59 PM
ladnarf1
New Member Forum
4
04-29-2021 11:53 PM
vapor2
West For Sale/Wanted
11
11-03-2020 03:38 PM
Skyl3r
New Member Forum
148
12-02-2019 04:51 PM
CMRine04
New Member Forum
15
07-29-2015 02:07 PM



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

Quick Reply: Power Loss after engine heats up



All times are GMT -5. The time now is 10:48 PM.