Idle issues - 460CC RX7 injectors, AEM EMS
06-02-2010, 10:13 PM
#1
Elite Member
Thread Starter
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,320
Total Cats: 13
Idle issues - 460CC RX7 injectors, AEM EMS
So I've lived with a crappy idle for quite some time now, and I'm hoping you folks can help me figure it out. Here's the important stuff:
97 motor
M-tuned dual feed rail
RX7 460CC injectors
AEM EMS ECU
Unknown Walbro fuel pump
My problem is that I can't get the car to idle any leaner then 12.5 to 1 fuel ratio. If I try to lean it out farther then that, the car starts sputtering and stumbling all over the place. When the car is in motion, running 14.5 to 1 is not a problem, it's only at idle that I have this issue. When the fuel ratio is 12.5 to 1 the car idles perfectly, but I'd be a lot happier with a leaner idle.
Now is it possible that a huge walbro fuel pump could cause me to have problems making the injectors idle any leaner? Several years ago (2003 I believe), my fuel pump failed and my mechanic went and put some expensive Walbro pump in. Ever since then my gas mileage has been the *****, but the car has always run fine. Could it be the pump is overloading the stock regulator and thereby limiting the injectors to be leaned out enough to idle at a proper value, or are the injectors just piles of crap that need to be replaced? I'm tempted to order a stock fuel pump, but also worried that my car is suddenly going to be crazy lean after.
Thanks for the help folks
97 motor
M-tuned dual feed rail
RX7 460CC injectors
AEM EMS ECU
Unknown Walbro fuel pump
My problem is that I can't get the car to idle any leaner then 12.5 to 1 fuel ratio. If I try to lean it out farther then that, the car starts sputtering and stumbling all over the place. When the car is in motion, running 14.5 to 1 is not a problem, it's only at idle that I have this issue. When the fuel ratio is 12.5 to 1 the car idles perfectly, but I'd be a lot happier with a leaner idle.
Now is it possible that a huge walbro fuel pump could cause me to have problems making the injectors idle any leaner? Several years ago (2003 I believe), my fuel pump failed and my mechanic went and put some expensive Walbro pump in. Ever since then my gas mileage has been the *****, but the car has always run fine. Could it be the pump is overloading the stock regulator and thereby limiting the injectors to be leaned out enough to idle at a proper value, or are the injectors just piles of crap that need to be replaced? I'm tempted to order a stock fuel pump, but also worried that my car is suddenly going to be crazy lean after.
Thanks for the help folks
Reply
0
0
06-02-2010, 10:16 PM
#2
Im running on stock pump, Id imagine you could get a stock pump if you wanted and just adjust the fuel accordingly, maybe remove the vacuum line on the FPR and see if it changes with what should be a higher fuel psi rate? Hint of maybe a bad regulator? Sorry I couldnt be of much help on this.
Reply
0
0
06-02-2010, 10:23 PM
#3
Elite Member
iTrader: (8)
Join Date: Dec 2008
Location: Kingston, Ontario
Posts: 2,910
Total Cats: 51
try adding some timing while pulling fuel.
you have sync'd timing with the ems right?
when i used your map and modded it for me... this is what i had to do...
i dont have my current ECU tune on my computer to compare to yours that you sent me, but i will get it this weekend.
you have sync'd timing with the ems right?
when i used your map and modded it for me... this is what i had to do...
i dont have my current ECU tune on my computer to compare to yours that you sent me, but i will get it this weekend.
Reply
0
0
06-02-2010, 10:26 PM
#4
Elite Member
Thread Starter
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,320
Total Cats: 13
try adding some timing while pulling fuel.
you have sync'd timing with the ems right?
when i used your map and modded it for me... this is what i had to do...
i dont have my current ECU tune on my computer to compare to yours that you sent me, but i will get it this weekend.
you have sync'd timing with the ems right?
when i used your map and modded it for me... this is what i had to do...
i dont have my current ECU tune on my computer to compare to yours that you sent me, but i will get it this weekend.
Last edited by dustinb; 06-02-2010 at 10:45 PM.
Reply
0
0
06-03-2010, 07:23 PM
#7
Elite Member
iTrader: (22)
Join Date: Dec 2006
Location: Sunny Spanish speaking Non US Caribbean
Posts: 3,224
Total Cats: 3
Post your cal. Let me see your idle settings and I'll suggest some changes.
BTW, my car idles at 14.7 to 15 without issues. My biggest problem used to be the a/c and I finally licked that too.
Reply
0
0
06-03-2010, 08:48 PM
#8
Elite Member
Thread Starter
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,320
Total Cats: 13
That won't help your issue either. I have 550cc injectors with a Walbro 255 and my idle is pretty good. It sure took me a long time to get there!
Post your cal. Let me see your idle settings and I'll suggest some changes.
BTW, my car idles at 14.7 to 15 without issues. My biggest problem used to be the a/c and I finally licked that too.
Post your cal. Let me see your idle settings and I'll suggest some changes.
BTW, my car idles at 14.7 to 15 without issues. My biggest problem used to be the a/c and I finally licked that too.
http://www.dbmiata.com/miataturbo/2010-06-03.V1.19.cal
Should also mention I have no idle motor hooked up.
Reply
0
0
Thread
Thread Starter
Forum
Replies
Last Post
StratoBlue1109
Miata parts for sale/trade
21
09-30-2018 01:09 PM
