Jump to content

Photo

'95 Miata, fuel starvation on hard left hand corners, what gives?

- - - - -

  • Please log in to reply
28 replies to this topic

#21
Keith Novak

Keith Novak

    Steadily Improving Member

  • SMembers
  • PipPipPipPipPip
  • 1,128 posts
  • Location:Seattle
  • Region:Northwest/Oregon
  • Car Year:1995
  • Car Number:88

 I was attempting to re-ask the same question Chris asked. Keith, what pump are you using.

I'm using the pump that came with my car when I bought it as a donor.  I thought it was stock but I can't say for sure.  It appeared to me when I first opened the tank that it did not look like a 125k filter so the pump may have been replaced.  If it's not the problem, it's due anyways just for peace of mind along with any other time limited parts. It's possible something going on in my pump could explain the weird AFRs I saw on the dyno as well.

 

It's definitely fuel path related and not electrically related since it is at very precise but different fuel levels on different tracks doing different things.  What really surprises me is that it is only one corner on each course and nowhere else but very bad at those 2 spots.  The conditions are just right that it passes a big bubble through the system where it never did before.

 

What's also a bit frustrating is that it's hard to duplicate.  I can't exactly go drive it around the block taking corners at 70 mph in various ways.  :)


Donor - Made PayPal donation Bona fide - A bonafide Spec Miata driver We have a Winnah! - Won their 1st race... Congratulations!

#22
Bench Racer

Bench Racer

    Different strokes for different folks : )

  • Members
  • PipPipPipPipPip
  • 5,415 posts
  • Location:Wauwatosa, WI
  • Region:Milwaukee
  • Car Year:1990
  • Car Number:14
Keith, do you have a fuel pressure gauge that you can see while driving when the engine faults????
Broken record - You are starting to sound like a broken record. Donor - Made PayPal donation Bona fide - A bonafide Spec Miata driver

#23
Keith Novak

Keith Novak

    Steadily Improving Member

  • SMembers
  • PipPipPipPipPip
  • 1,128 posts
  • Location:Seattle
  • Region:Northwest/Oregon
  • Car Year:1995
  • Car Number:88

I don't but I can add one.  No offense but what will it tell me when it coughs other than, "ain't got no gas in it"?  I did a 20 min session just to listen to it and it sounds just like if you've drained the tank, but didn't leave the jumper in the diag. box to prime the system before trying to start.... nothing, nothing, cough, fire. 


Donor - Made PayPal donation Bona fide - A bonafide Spec Miata driver We have a Winnah! - Won their 1st race... Congratulations!

#24
Bench Racer

Bench Racer

    Different strokes for different folks : )

  • Members
  • PipPipPipPipPip
  • 5,415 posts
  • Location:Wauwatosa, WI
  • Region:Milwaukee
  • Car Year:1990
  • Car Number:14

 On one course, it will cut out with less than 3.5 gallons but only on one specific corner after a set of switchbacks. 

 

On another it will cut out with 2.5 gallons under breaking after a couple seconds of slight left hand turn leading to the braking zone. 

 

It happens nowhere else.

 

 Maybe it's come loose or maybe this is something else entirely.

I question the regulator being the issue in my case.  It started last year with the stock regulator.  I just installed the Aeromotive and it did the exact same thing. 

 

Same corner and precisely the same 3.5 gallons after much testing. 

 

I have run this track multiple times before (The Ridge for those in the area) with no issues including a 6hr enduro. 

 

Seems there is a message within these comments above.

Do other folks at the same track with the same year car have your same fuel issue?

Are all NA fuel tanks the same? 

No offense intended, if I knew I had zero fuel pressure under your very specific conditions I would pull the pump assembly and do pressure testing with the sock off and the inlet pluged. If no leak issue, I would install a new fuel pump.

As Dave Wheeler says, well intended. Take my comments as intended to spur thoughts to eliminate your issue.


Broken record - You are starting to sound like a broken record. Donor - Made PayPal donation Bona fide - A bonafide Spec Miata driver

#25
Jim Drago

Jim Drago

    East Street Racing / 2 Time National Champion

  • Administrators
  • 6,393 posts
  • Location:Memphis, Tn
  • Region:Mid South
  • Car Year:2005
  • Car Number:2

I don't but I can add one.  No offense but what will it tell me when it coughs other than, "ain't got no gas in it"?  I did a 20 min session just to listen to it and it sounds just like if you've drained the tank, but didn't leave the jumper in the diag. box to prime the system before trying to start.... nothing, nothing, cough, fire. 

 

Keith

I feel fairly certain the new pump you are installing should do away with this issue. That sounds like many of teh fuel pump issues we have had. I would like to know what causes it and why it always starts in those lefts.. But ultimately, I just want it fixed. :) Please keep us posted.

Jim


East Street Auto Parts
Jim@Eaststreet.com
800 700 9080

NASA Champs Winner - NASA Champs Winner Hoosier Super Tour points Champion - Hoosier Super Tour points Champion ARRC Champion - Won the ARRC Race in a Spec Miata Series Champ - Won a points based series in a Spec Miata BFG Supertour Winner - Majors Winner - Circuit of the Americas Winner - We have a Winnah! - Won their 1st race... Congratulations! June Sprints winner  - June Sprints winner June Sprints winner  - June Sprints winner June Sprints winner  - June Sprints winner June Sprints winner  - June Sprints winner SCCA National Champion - Won SCCA Runoffs at Road America SCCA National Champion - Won SCCA Runoffs at Road America

#26
Keith Novak

Keith Novak

    Steadily Improving Member

  • SMembers
  • PipPipPipPipPip
  • 1,128 posts
  • Location:Seattle
  • Region:Northwest/Oregon
  • Car Year:1995
  • Car Number:88
Fuel pump it is!

I'm back at the track where it would cut out at 3.5 gallons and getting it down to just over 1 with no sign of a cutout after installing a new pump.

Thanks all!
Donor - Made PayPal donation Bona fide - A bonafide Spec Miata driver We have a Winnah! - Won their 1st race... Congratulations!

#27
ChrisA

ChrisA

    Veteran Member

  • Members
  • PipPipPipPipPip
  • 643 posts
  • Location:Richmond, VA
  • Region:NCR
  • Car Year:1999
  • Car Number:58
Keith, what brand pump did you install?

Chris

 

Happiness is a dry martini and a good woman ... or a bad woman.
- George Burns


#28
Keith Novak

Keith Novak

    Steadily Improving Member

  • SMembers
  • PipPipPipPipPip
  • 1,128 posts
  • Location:Seattle
  • Region:Northwest/Oregon
  • Car Year:1995
  • Car Number:88

I installed a Denso 950-0118.  From Mazda now you can only buy it as the entire assembly with the steel tubing, cap, and the whole shebang.  It seemed like a decent one and it's working now.  The fuel pressure did go up one psi.  I will be very interested to put it on a dyno and see if it fixed my weird AFR rising fuel rate issue.


Donor - Made PayPal donation Bona fide - A bonafide Spec Miata driver We have a Winnah! - Won their 1st race... Congratulations!

#29
Sphinx

Sphinx

    Veteran Member

  • Members
  • PipPipPipPipPip
  • 589 posts
  • Location:ATL & SFO
  • Region:ATL

Ran into this problem yesterday at the turn 13-15 complex (sustained left hander) at Atlanta Motorsports Park.  Car had 4 gallons at the start of the session and then "lost power" at 5800 RPM for about a second.  And then back to normal.  Happened no where else on the track on two laps back to back.  Was told by the on-site prep shop that this is common in that turn in an SM, some cars worse than others.  Mine had about 2-2.5 gallons left when it lurched.

 

Will look at getting a new fuel pump per this thread.






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users