Went to get a tune a few weeks back and got some bad news... - RX7Club.com - Mazda RX7 Forum

Go Back  RX7Club.com - Mazda RX7 Forum > Generation Specific > 3rd Generation Specific (1993-2002)
Reload this Page >

Went to get a tune a few weeks back and got some bad news...

3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.

Went to get a tune a few weeks back and got some bad news...

Reply

 
 
 
Old 07-09-18, 01:59 PM
  #1  
Junior Member
Thread Starter
 
IceMan1990's Avatar
 
Join Date: Apr 2012
Location: Alamogordo, NM
Posts: 45
Thanked 2 Times in 2 Posts
Went to get a tune a few weeks back and got some bad news...

Hi guys!! This is my attempt to get more active on the forums since I bought my FD and have settled down since returning from overseas.

So the issue I was having with my car after the first month was that it was running insanely rich, to the point where my co-workers would regularly complain about the smell of gas (and premix) while we were leaving work. After a few mountain runs, my friends were amused at how much flames my car spit out, but on the inside I knew this wasn't optimal. And it's only boosting .4 bar, which pisses me off!!

So I took it to El Paso to get a tune. After talking to the tuner and the technician, they decided to do a compression test before hooking it up to the dyne. Here are the results.




My problem is that the PO claims that the engine was rebuilt in September. The car runs fine, there's no signs of the engine going as far as I can tell (other than the frequent flooding due to low compression). I have since bought a 2nd car as a daily driver and I'm considering letting my technician do the rebuild and single turbo conversion. It's not in dire need of a rebuild, but if I can't tune it, is it worth starting from scratch?

Thanks guys!!
IceMan1990 is offline  
Reply With Quote
Old 07-09-18, 02:15 PM
  #2  
Senior Member
 
Join Date: Dec 2016
Location: Florida
Posts: 331
Thanked 8 Times in 8 Posts
If you trust you mechanic/tech do the rebuild. The compression test has to be done correctly. If you have compression of 70's, your engine is due. If you do a rebuild, do single turbo conversion while you are at it. All relies on your trust on your mechanic and his competence. If you have doubts, shop around..
Red94fd is offline  
Reply With Quote
Old 07-09-18, 02:25 PM
  #3  
SEMI-PRO
iTrader: (2)
 
ZoomZoom's Avatar
 
Join Date: Feb 2001
Location: New Jersey
Posts: 2,834
Thanked 21 Times in 21 Posts
Was it done with a rotary compression tester?
ZoomZoom is offline  
Reply With Quote
Old 07-09-18, 03:46 PM
  #4  
RX-7 Bad Ass
iTrader: (50)
 
DaleClark's Avatar
 
Join Date: Jan 2002
Location: Pensacola, FL
Posts: 10,720
Thanked 171 Times in 145 Posts
A motor with low compression won't start as easily, will be lacking in low-end power, may stall, etc. Also the running rich holds true as well.

The motor being recently rebuilt doesn't mean much, you can put most anything together and have a motor that will start, run and drive but won't be the tightest or longest lasting motor.

Would be nice to have a compression test with a proper rotary tester to make sure, but the evidence backs up the claim.

Big thing here is to take your time and evaluate how you want to remedy the problem. There's doing it yourself all the way up to shipping it to a rotary shop with a blank check and lots in between. Big thing is there is no end of money you can spend on an engine, be realistic and set a vision for what you want.

Regardless keep that CYM on the road and happy!

Dale
DaleClark is offline  
Reply With Quote
Old 07-09-18, 04:56 PM
  #5  
Junior Member
Thread Starter
 
IceMan1990's Avatar
 
Join Date: Apr 2012
Location: Alamogordo, NM
Posts: 45
Thanked 2 Times in 2 Posts
The test with done with a Mazda Rotary compression tester. He even did it a 3rd time to demonstrate how to do it and verify the numbers.

Thanks for all the replies guys. Iím waiting on the estimate with the parts list and final prices for everything, including the single turbo conversion.

Best believe I will do what it takes to keep her on the road. Waited 7 years to get this car.

Last edited by IceMan1990; 07-09-18 at 04:59 PM.
IceMan1990 is offline  
Reply With Quote
Old 07-11-18, 06:24 AM
  #6  
Rotary Specialists
RX7Club Vendor
iTrader: (11)
 
Banzai-Racing's Avatar
 
Join Date: Jan 2008
Location: Indiana
Posts: 4,462
Thanked 52 Times in 42 Posts
What was the RPM reading for those numbers and what is your elevation? Was the throttle held open during the test?

I have seen plenty of falsified compression tests.

Last edited by Banzai-Racing; 07-11-18 at 06:27 AM.
Banzai-Racing is offline  
Reply With Quote
The Following 2 Users Say Thank You to Banzai-Racing For This Useful Post:
dfwrx7 (07-11-18), GoodfellaFD3S (07-11-18)
Old 07-11-18, 05:47 PM
  #7  
Original Gangster/Rotary!
iTrader: (204)
 
GoodfellaFD3S's Avatar
 
Join Date: Mar 2001
Location: FL-->NJ/NYC again!
Posts: 29,966
Thanked 100 Times in 89 Posts
^This man is on point
GoodfellaFD3S is offline  
Reply With Quote
Old 07-11-18, 09:35 PM
  #8  
Junior Member
Thread Starter
 
IceMan1990's Avatar
 
Join Date: Apr 2012
Location: Alamogordo, NM
Posts: 45
Thanked 2 Times in 2 Posts
Iím not certain of the RPM numbers but the test was done in El Paso, TX.

According to a few of the rotary guys in Albuquerque, the symptoms Iím having are in line with a low compression motor. No low end power, problems on hot starts, constant stalling, and frequent flooding just to name a few.

Falsified compression test? Please do tell...
IceMan1990 is offline  
Reply With Quote
Old 07-11-18, 10:25 PM
  #9  
38 years of 7's
iTrader: (1)
 
mikejokich's Avatar
 
Join Date: Jan 2012
Location: Alabama
Posts: 125
Thanked 14 Times in 14 Posts
I believe Iceman you misunderstood the two posts from two other very knowledgeable members. As I understood it, they did not believe that the shop that did your compression test purposely falsified the test. They were just pointing out that if the test is not done a certain way for a rotary engine, even with a rotary compression tester, the compression reading will be incorrectly low and the test is inaccurate or false. I don't think you would want to rebuild your engine if it wasn't needed. The two posters are trying to save you time and money in pointing these things out. That's all.
Mike
mikejokich is offline  
Reply With Quote
Old 07-11-18, 11:24 PM
  #10  
#include <stdhdr.h>
 
dfwrx7's Avatar
 
Join Date: Aug 2001
Location: Allen, Tx
Posts: 369
Thanked 3 Times in 3 Posts
For example, if the throttle isn't held open during the test the compression values will be artificially low simple because the butterfly valves are obstructing the intake. Likewise if done in Denver (or El Paso) you'll get a much different value than I will here in Dallas which is a mere 600ft above sea level. Likewise I would expect a different value than in Pensacola.
dfwrx7 is offline  
Reply With Quote
Old 07-12-18, 01:28 AM
  #11  
Very Stable Genius
iTrader: (1)
 
WANKfactor's Avatar
 
Join Date: May 2011
Location: omnipresent
Posts: 1,164
Thanked 57 Times in 50 Posts
Really even readings across all 6 faces, you wouldnt see that on a crapped out engine too often.
might just need a tune.
WANKfactor is offline  
Reply With Quote
Old 07-12-18, 06:59 AM
  #12  
Rotary Specialists
RX7Club Vendor
iTrader: (11)
 
Banzai-Racing's Avatar
 
Join Date: Jan 2008
Location: Indiana
Posts: 4,462
Thanked 52 Times in 42 Posts
Additionally if the rpm was 175rpm the reading must be normalized to 250rpm which yields much higher results. Weak battery, high altitude, closed throttle all effect readings.

here is a thread I created on the subject https://www.rx7club.com/3rd-generati...sting-1098715/

All of your symptoms also describe a crappy tune.

Last edited by Banzai-Racing; 07-12-18 at 07:08 AM.
Banzai-Racing is offline  
Reply With Quote
The Following User Says Thank You to Banzai-Racing For This Useful Post:
dfwrx7 (07-12-18)
Old 07-12-18, 11:57 AM
  #13  
It Just Feels Right
iTrader: (10)
 
TomU's Avatar
 
Join Date: Feb 2014
Location: Arlington, VA
Posts: 1,450
Thanked 26 Times in 25 Posts
check it with a piston tester to see if you get a different reading
TomU is online now  
Reply With Quote
Old 07-12-18, 11:58 AM
  #14  
Junior Member
Thread Starter
 
IceMan1990's Avatar
 
Join Date: Apr 2012
Location: Alamogordo, NM
Posts: 45
Thanked 2 Times in 2 Posts
Ok gentlemen, Iím willing to go with a retune to see if that helps at all.

In case my tuner wonít (turned me away after compression test due to liability concerns), does anyone know any reputable Adaptronic tuners?
IceMan1990 is offline  
Reply With Quote
Old 07-12-18, 12:05 PM
  #15  
#include <stdhdr.h>
 
dfwrx7's Avatar
 
Join Date: Aug 2001
Location: Allen, Tx
Posts: 369
Thanked 3 Times in 3 Posts
Call Steve Kan @ PRT Performance in Ft. Worth. He'll steer you right.

PRT Performance | Lewisville Performance Shop | Dallas Auto Services | Dyno Tuning
dfwrx7 is offline  
Reply With Quote
Old 07-12-18, 12:23 PM
  #16  
It Just Feels Right
iTrader: (10)
 
TomU's Avatar
 
Join Date: Feb 2014
Location: Arlington, VA
Posts: 1,450
Thanked 26 Times in 25 Posts
I would still double check your compression first
TomU is online now  
Reply With Quote
Old 07-13-18, 04:37 PM
  #17  
Senior Member
iTrader: (5)
 
Join Date: Apr 2006
Location: sb
Posts: 723
Thanks: 0
Thanked 20 Times in 18 Posts
Don't just go out and get a re-tune as you might just be wasting money. Nobody is saying that the shop you've gone to is steering you wrong just that you should have it double checked before you axe the engine.
dguy is online now  
Reply With Quote
The Following User Says Thank You to dguy For This Useful Post:
IceMan1990 (07-16-18)
Old 07-16-18, 01:01 PM
  #18  
Junior Member
Thread Starter
 
IceMan1990's Avatar
 
Join Date: Apr 2012
Location: Alamogordo, NM
Posts: 45
Thanked 2 Times in 2 Posts
Understood!
IceMan1990 is offline  
Reply With Quote
 
 
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
64mgb
1st Generation Specific (1979-1985)
31
09-24-06 05:06 PM
felixwankel88
2nd Generation Specific (1986-1992)
18
06-23-05 11:20 AM
MazdaRx7Power
2nd Generation Specific (1986-1992)
1
05-07-02 03:25 PM


Thread Tools
Search this Thread
Quick Reply: Went to get a tune a few weeks back and got some bad news...


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.