crashed240z Posted May 24, 2011 Share Posted May 24, 2011 Ok guys here is a quick disclaimer. I have been able to find all the information I needed so far, from this site by searching. I am stumped right now as to what is causing my current issue. If you can point me to a previous thread I'll gladly read it, but I haven't found one. The problem I am having is I cannot make it run any leaner at idle then about 10.5:1 AFR No matter what I input into the VE table. I have gone to a reputable dyno shop and their AFR meter matched mine so my gauge isn't off. Never got to do a dyno pull since we couldn't even control the idle mixture. Here is what I am running. With the help from this board L28ET MSII V 3.0 EDIS PWM flyback is active. Toyota supra 440cc injectors (Low impedance from my understanding) Fuel rail pressure is at 60 psi 240sx throttle body Magnecor wires Brand new NGK plugs Injector opening times are set to .9 ms injector firing has been switched between alternating and simultaneous with no effect. I have no IAC valve but I didn't think this would cause my issue am I wrong? I'm kind of stumped at this issue as the car runs fine except this idle problem. Any help is appreciated Thanks for your time. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted May 24, 2011 Share Posted May 24, 2011 What is your timing advance at idle? Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted May 24, 2011 Share Posted May 24, 2011 (edited) Try lowering the ReqFuel. Do you have it in closed loop or open loop mode? Edited May 24, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
crashed240z Posted May 24, 2011 Author Share Posted May 24, 2011 The timing is about 18 degrees at idle. It idles at 1000 rpm. I have advanced it and retarded it to no real effect. I used the fuel calculator and came up with 5.8. I'll lower it and see what happens. But I am not going to be able to look at it till Wednesday afternoon. As for closed loop open loop I'm honestly not not sure what that means, Sorry still learning MSII. Thanks for your fast replies I will get back as soon as I can after checking what you have suggested. Quote Link to comment Share on other sites More sharing options...
Noddle Posted May 24, 2011 Share Posted May 24, 2011 Fuel rail pressure is at 60 psi Is this a little high ?, I run my at about 40psi ( L24, 440cc injectors ) Nigel Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted May 24, 2011 Share Posted May 24, 2011 (edited) Open loop would be non-ego feedback. In other words, the O2 sensor signal value is not used to modify the pulsewidth (VE numbers) while running. Closed loop is when the O2 signal has authority to modify the pulsewidth, in order to maintain your AFR table settings. If it's in closed loop (EGO control enabled), and your AFR table is calling for 10:1 AFR, then no matter where you try to move your VE values, the ECU will fight you and try to maintain 10:1. This will vary depending on the authority given to the O2 signal. Edited May 24, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
crashed240z Posted May 26, 2011 Author Share Posted May 26, 2011 Oh ok I got you. I have run the car in both open loop and closed loop. It doesn't seem to care. Controller authority is at 25%. AFR tables are set at 14:1 at idle. Still idles at 10.5 -11 AFR. I have not been able to adjust the req fuel as I haven't been able to go home yet. The fuel pressure is at 60 psi because I am running a Camaro gas tank and that is the stock pressure from the pump. Not sure if this is good or bad. I wont be able to look at the car till sunday it looks like. I will get back as soon as I can look at it more thoroughly. Thank you again. Quote Link to comment Share on other sites More sharing options...
NewZed Posted May 26, 2011 Share Posted May 26, 2011 Is it possible to log and view the actual injector open duration? This would show you how MS is controlling fuel. And is there a minimum duration for Megasquirt? With big injectors and high pressure, maybe you're at the minimum duration. Just guessing, I know a little data acquisition and control but don't have Megasquirt. Quote Link to comment Share on other sites More sharing options...
thayeti Posted May 30, 2011 Share Posted May 30, 2011 40psi = 440cc/min 60psi = 537cc/min 60/40 = 1.5 square root of 1.5 is 1.22 440*1.22 = 537cc/min You have increased your injector output by increasing the fuel pressure so much. If you entered 537cc/min in your Req/Fuel section MS will be injecting the amount of fuel it is expecting to inject. I am an active member on Zcar and a troll here. Thought I should start getting my foot in the door here. Quote Link to comment Share on other sites More sharing options...
crashed240z Posted June 8, 2011 Author Share Posted June 8, 2011 OK I have been able to look at it again. The injector pulse width is like 3.2 ms. at idle I calculated the req fuel at 5.7 with 440cc injectors at 60psi so like thayeti said 537cc. I had to cut the req fuel in half before it started to idle at 13:1 AFR This has been the only way I have been able to affect the idle mixture so far. When I did this the pulse width dropped to 1.3 Whether it is in open loop or closed loop it doesn't seem to care. If I give it more then 40% controller authority the engine dies. Is there something simple that I might be missing in the MSll set up? Is there something I should be looking for? The injector drivers are not overheating, the PWM is active at 30%, AFR table is set to 14.7:1 I"m a little lost... The engine runs strong it just idles stupidly rich. Thanks for any help guys. Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted June 8, 2011 Share Posted June 8, 2011 Does MSII have "Idle VE" as an option for idle control? On my MS III there is an option for "idle VE" where it has a different table set for idle, similar to idle advance, where if TPS is under X% and MAP is between values X and Y after a delay of Z seconds then it references the "idle VE" settings rather than your regular VE table. Having this feature turned on when it is not set properly can make you think that MS is not responding when in fact it is, but it is using your "idle VE" settings rather than your normal "VE" settings in it's injector pulswidth equation. My recomendation would be to search your menu in tunerstudio/megatune and see if you have an "idle VE" setting and turn it off for now, then experiment with it after you have the motor running smoothly on the standard VE table. Quote Link to comment Share on other sites More sharing options...
DCZ Posted August 22, 2011 Share Posted August 22, 2011 Hey Crashed240z, Did you ever figure out your idle AFR problem? I am having very similar symptoms on my new MS install. Idling pig rich but revs good otherwise. I haven't driven it yet because I'm firming up the wiring. If I try to lean the idle using the V/E table, I get bad off-idle stumbling. stock L28et MSII board V3.57 TunerStudio Stock Optical CAS MS triggering stock ignitor Ford XR4Ti injectors 370cc Stock idle control valve Timing 15 deg. LC-1 AFR Quote Link to comment Share on other sites More sharing options...
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