78zstyle Posted April 26, 2012 Share Posted April 26, 2012 I have so much trouble with this darn thing. AFRs keep fluctuating from 12-16 or what have you. In the mornings when I first start it, it runs pig rich with no warmup acceleration but runs much better when warm. My idle AFRs just keep going up and down, taking my RPM with it. Cruising is ok. I've attached my tune and a log of it idling showing whats going on. Any help would be appreciated. I have all EGO corrections turned off. Is it possible that the Original BG code just doesn't work right? Datalog42512.txt Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted April 26, 2012 Share Posted April 26, 2012 (edited) What is your battery voltage doing at idle? Is it fluctuating as well? You may have to adjust injector compensation tables. I've recently adjusted mine (different system, not MS), and it has helped greatly with a surging idle I'd occasionally get. Edited April 26, 2012 by Six_Shooter Quote Link to comment Share on other sites More sharing options...
78zstyle Posted April 26, 2012 Author Share Posted April 26, 2012 What is your battery voltage doing at idle? Is it fluctuating as well? You may have to adjust injector compensation tables. I've recently adjusted mine (different system, not MS), and it has helped greatly with a surging idle I'd occasionally get. My battery voltage dies as the idle goes down (while its going rich at the same time). I've tried adjusting the compensation down and it gets way worse. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted April 26, 2012 Share Posted April 26, 2012 My battery voltage dies as the idle goes down (while its going rich at the same time). I've tried adjusting the compensation down and it gets way worse. Think about that for a minute..... Ok.... Try adjusting it the other way, (increasing the numbers) at lower voltage. Quote Link to comment Share on other sites More sharing options...
78zstyle Posted April 26, 2012 Author Share Posted April 26, 2012 Think about that for a minute..... Ok.... Try adjusting it the other way, (increasing the numbers) at lower voltage. Not supposed to go past .2 on that value. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted April 26, 2012 Share Posted April 26, 2012 A wise tuner once said: "Give the engine what it wants" Why are you not supposed to go past ".2" on that value? Quote Link to comment Share on other sites More sharing options...
78zstyle Posted April 26, 2012 Author Share Posted April 26, 2012 Gives a warning not to do it unless you are an EFI expert, plus I don't see anyone else using more than .2 correction, so I really think we are focusing on something other than the problem. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 26, 2012 Share Posted April 26, 2012 Are EGO corrections turned off? Quote Link to comment Share on other sites More sharing options...
78zstyle Posted April 26, 2012 Author Share Posted April 26, 2012 Are EGO corrections turned off? Yes they are, that was one of my first things to check. Is it possible that maybe there is electrical interference getting to my injector wires messing with them? Quote Link to comment Share on other sites More sharing options...
mobythevan Posted April 26, 2012 Share Posted April 26, 2012 I don't know any details of your car. Is this a stock cam and do you use a stock style cold idle valve that closes as coolant heats up? Are you using high or low impedance injectors and if they are low do you have dropping resistors or do you use PWM? Just trying to see if anything seems obvious to me that would make your idle hunt. Large injectors that are hard to control will cause it. A large cam may cause it, but I haven't personally witnessed how large cams act with megasquirt. Quote Link to comment Share on other sites More sharing options...
78zstyle Posted April 26, 2012 Author Share Posted April 26, 2012 I don't know any details of your car. Is this a stock cam and do you use a stock style cold idle valve that closes as coolant heats up? Are you using high or low impedance injectors and if they are low do you have dropping resistors or do you use PWM? Just trying to see if anything seems obvious to me that would make your idle hunt. Large injectors that are hard to control will cause it. A large cam may cause it, but I haven't personally witnessed how large cams act with megasquirt. Im using the 240sx tps. Stock cam. Low impedance injectors with resistors no pwm. Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted April 27, 2012 Share Posted April 27, 2012 78zstyle, I downloaded your datalog and converted to .xls to open with MegaLogView. I'm guessing something must be lost in transation. Your max RPMs are 71? Is that correct? And MAP only varies between 21 and 65? PW is pretty consistenly 1.3ms with occasional spikes to 6.3? I'm assuming your file didn't translate correctly, or I did something wrong, because that data log is junk. No car will run like that. Do these numbers correspond with what you are seeing? Quote Link to comment Share on other sites More sharing options...
78zstyle Posted April 27, 2012 Author Share Posted April 27, 2012 78zstyle, I downloaded your datalog and converted to .xls to open with MegaLogView. I'm guessing something must be lost in transation. Your max RPMs are 71? Is that correct? And MAP only varies between 21 and 65? PW is pretty consistenly 1.3ms with occasional spikes to 6.3? I'm assuming your file didn't translate correctly, or I did something wrong, because that data log is junk. No car will run like that. Do these numbers correspond with what you are seeing? Oh wow, you are right, I didn't look closely enough to see how low those RPMs were. In megatune while its running it shows the correct RPM, what gives? Quote Link to comment Share on other sites More sharing options...
78zstyle Posted June 6, 2012 Author Share Posted June 6, 2012 I thought I'd give this a bump. I recently transplanted my engine into a new chassis and got a chance to double check all wiring. Everything is wired correctly, all grounds good.. etc. It's still doing this.. I really am considering just ripping megasquirt out and going with another ECU (Z31) Quote Link to comment Share on other sites More sharing options...
loy Posted June 6, 2012 Share Posted June 6, 2012 How bout that datalog? Quote Link to comment Share on other sites More sharing options...
letitsnow Posted June 6, 2012 Share Posted June 6, 2012 post another datalog that's the regular format, just put it in a zip file and upload it. Quote Link to comment Share on other sites More sharing options...
78zstyle Posted June 7, 2012 Author Share Posted June 7, 2012 Gotcha ill upload it tomorrow night when i get to my dads place. Quote Link to comment Share on other sites More sharing options...
78zstyle Posted June 8, 2012 Author Share Posted June 8, 2012 Good news, I had my father install the "dave capacitor" and it totally killed my RPM spike. I am still having a surging idle though. Im hoping that is tune related. I added my datalog just in case you see something. datalog201206072020.rar Quote Link to comment Share on other sites More sharing options...
letitsnow Posted June 8, 2012 Share Posted June 8, 2012 Turn off ego correction first, then change the VE map to get it to idle nice. Any idea why rpm is divided by 100, possibly part of the BG code? Is MAT really 130*? Sitting idling for quite a while? Quote Link to comment Share on other sites More sharing options...
78zstyle Posted June 8, 2012 Author Share Posted June 8, 2012 I cant get it to idle nice. It surges the whole time.. Just not as bad. I believe that mat tempature is correct. I am using the gm iat sensor. I was sitting for a bit. I am also using a j pipe Quote Link to comment Share on other sites More sharing options...
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