Guest |580| Posted September 25, 2011 Report Share Posted September 25, 2011 I've got a CA18 turbo with rx8 440cc injectors and am experiencing the following: At cruise with AFR's being held at a desired 14.7 if I encounter anything that changes the load like a small incline or a small change of the TPS, my AFR's will go lean to around 15.7 which is enough to cause a slight hesitation. So after adjusting the accel enrichment settings for quite some time I discovered that no matter how much enrichment I added when I add the slightest bit of throttle input, my AFR's always go lean for a moment before fattening up. I'm not sure if it's injector response or what that could be causing this. Any ideas? Quote Link to comment Share on other sites More sharing options...
Simon Posted September 26, 2011 Report Share Posted September 26, 2011 Another area that can have an effect will be injector timing. (assuming you are running sequential) Not sure how much of an effect this will have. Quote Link to comment Share on other sites More sharing options...
gunnerthesnowman Posted September 26, 2011 Report Share Posted September 26, 2011 I've got a CA18 turbo with rx8 440cc injectors and am experiencing the following: At cruise with AFR's being held at a desired 14.7 if I encounter anything that changes the load like a small incline or a small change of the TPS, my AFR's will go lean to around 15.7 which is enough to cause a slight hesitation. So after adjusting the accel enrichment settings for quite some time I discovered that no matter how much enrichment I added when I add the slightest bit of throttle input, my AFR's always go lean for a moment before fattening up. I'm not sure if it's injector response or what that could be causing this. Any ideas? I had this same problem with my turbo sled , i though the same thing as you , have to increase enrichment , the problem ended up being to much enrichment which gave a miss fire which showed up as a high ( lean ) AFR , i took some enrichment out and no more problem AFR stays good , and sled works nuts. Quote Link to comment Share on other sites More sharing options...
Guest |580| Posted September 27, 2011 Report Share Posted September 27, 2011 I had this same problem with my turbo sled , i though the same thing as you , have to increase enrichment , the problem ended up being to much enrichment which gave a miss fire which showed up as a high ( lean ) AFR , i took some enrichment out and no more problem AFR stays good , and sled works nuts. I tried running with high enrichment, high enough to cause a 10:1 to appear on my wideband and kill any hope of power (but still deliver the lean spot just before the enrichment registers. I've also tried running with minimum enrichment and the same thing occurs. I'm really at a loss here. As for the idea of injector timing, I'm not sure how to attack that one because I don't know what I need to know to make that work properly. I'm using the default of 340deg and it has seemed to work fine, but I'm not sure if that should be altered. I've been so daring as to change it by 40deg +- and it didn't make a difference. I will note however that my SC300 with a PowerFC had this same issue and getting the "Injector Delay" settings correct seemed to resolve this issue more than any other thing. Is there an equivalent setting on the Vi-PEC? I tried the dead time settings but with no luck either. Quote Link to comment Share on other sites More sharing options...
Guest |851| Posted September 27, 2011 Report Share Posted September 27, 2011 I had similar problem in my setup, the root cause was that the idle throttle position was too high, so on low loads with low TP i had the idle valve open and some throttle open as well. dunno how your cruise is setup to work. Quote Link to comment Share on other sites More sharing options...
Guest |823| Posted September 28, 2011 Report Share Posted September 28, 2011 hello, check your throttle body for signs of damage from throttle plate,as agging will cause a small dent when throttle is resting and when you tip in you will suddenly have a larger section(only by few mm) and then it goes back to normal section, and beeing speed density pressure is same but flow diffrent.you can try and fix it by watching tps and rescaling around that area a 4d fuel map so you have lots of resolution in that area.....so check throotle body, plate, resting position minimum....Leaks around throttle plate axle Quote Link to comment Share on other sites More sharing options...
gunnerthesnowman Posted September 28, 2011 Report Share Posted September 28, 2011 I tried running with high enrichment, high enough to cause a 10:1 to appear on my wideband and kill any hope of power (but still deliver the lean spot just before the enrichment registers. I've also tried running with minimum enrichment and the same thing occurs. I'm really at a loss here. As for the idea of injector timing, I'm not sure how to attack that one because I don't know what I need to know to make that work properly. I'm using the default of 340deg and it has seemed to work fine, but I'm not sure if that should be altered. I've been so daring as to change it by 40deg +- and it didn't make a difference. I will note however that my SC300 with a PowerFC had this same issue and getting the "Injector Delay" settings correct seemed to resolve this issue more than any other thing. Is there an equivalent setting on the Vi-PEC? I tried the dead time settings but with no luck either. Yes , just decreasing the Accel clamp table was not enough , i also had to decrease the Accel Hold and increase the Accel Decay , the hesitation i had was from just off idle to about 1/2 TPS, any time i move the TPS i had a hesitation ,it showed as a high (lean) AFR then went low (rich) , i had this problem for two years tuning with a Vipec dealer/tuner and he could not get it to work right , he was tuning main fuel/ingition tables making up 3D,4D,5D tables , The standalone ECU is only as good as the tuner , and there is a lot of bad so called TUNERS out there , i can show you the bills to proof it. Tuning a standalone 1L turbocharge sled for 400+HP and still have good low end/off boost throttle response is not easy You say this happen at a cruise , so your TPS should be well of of its stop , may be something different in your case. Quote Link to comment Share on other sites More sharing options...
Guest |823| Posted September 29, 2011 Report Share Posted September 29, 2011 what fpr do you have? Quote Link to comment Share on other sites More sharing options...
Guest |140| Posted September 29, 2011 Report Share Posted September 29, 2011 Claudiumxg What is fpr? Augusto Quote Link to comment Share on other sites More sharing options...
Guest |823| Posted September 29, 2011 Report Share Posted September 29, 2011 Fuel pressure regulator Quote Link to comment Share on other sites More sharing options...
Guest |140| Posted September 29, 2011 Report Share Posted September 29, 2011 Claudiomxg Fuel menu Accel Enrichment Deadband Accel - 0.2% of TP is equal to 2%. Watch this leads to error in this calibration. Sorry for the poor english Augusto Quote Link to comment Share on other sites More sharing options...
Guest |823| Posted September 30, 2011 Report Share Posted September 30, 2011 not shure if i get it right , but you should not have negative value in accel deadband, you should have something betwen 0,5 and 1%. this does not add fuel just arms the enrichment strategy Claudiomxg Fuel menu Accel Enrichment Deadband Accel - 0.2% of TP is equal to 2%. Watch this leads to error in this calibration. Sorry for the poor english Augusto Quote Link to comment Share on other sites More sharing options...
gunnerthesnowman Posted September 30, 2011 Report Share Posted September 30, 2011 Ya , stupit why they would do it that way , mine is set for .6% so 6% TPS movement and the Accel enrichment kicks in. Claudiomxg Fuel menu Accel Enrichment Deadband Accel - 0.2% of TP is equal to 2%. Watch this leads to error in this calibration. Sorry for the poor english Augusto Quote Link to comment Share on other sites More sharing options...
Guest |140| Posted October 2, 2011 Report Share Posted October 2, 2011 CLAUDIUXG The number is not negative. accel deadband: 0.2% equals 2%. Do the test in your ecu. Augusto. Quote Link to comment Share on other sites More sharing options...
Guest |823| Posted October 3, 2011 Report Share Posted October 3, 2011 ok, then just make it slightly bigger ps. did you manage to check your fpr? Quote Link to comment Share on other sites More sharing options...
Guest |708| Posted October 3, 2011 Report Share Posted October 3, 2011 To the original poster, BoostLee I've got a CA18 turbo with rx8 440cc injectors and am experiencing the following: At cruise with AFR's being held at a desired 14.7 if I encounter anything that changes the load like a small incline or a small change of the TPS, my AFR's will go lean to around 15.7 which is enough to cause a slight hesitation. So after adjusting the accel enrichment settings for quite some time I discovered that no matter how much enrichment I added when I add the slightest bit of throttle input, my AFR's always go lean for a moment before fattening up. I'm not sure if it's injector response or what that could be causing this. Any ideas? Did you ever resolve the problem? This is exactly the same problem I have been facing for a year now. I have tried everything you said you have done in the accel enrichment (both obscenely high and low values) and it did not help. I found the only way to temporarily alleviate the problem was to create a 4D table that uses the x-axis of "TPS delta" and y-axis of "MAP" to try and add fuel immediately as the tip-in occurs. It has helped, but by no means has fixed the issue, and does not seem like the proper solution. Also, in my case, when I slightly close the throttle (I suppose you could call it, tip-out), my AFR's become rich. Do you have this problem as well? Please let me know, as you are the only other person on this forum who has also had this problem. Hopefully we can work together to figure this out. Mike Quote Link to comment Share on other sites More sharing options...
Guest |823| Posted October 4, 2011 Report Share Posted October 4, 2011 hello, it seems this problem is relatively isolated and seems to be related to a particular set up. you have to understand that speed density alone on map without tps corection is a very rough aproximation of air flow, and tip in enrichment is a old age problem with sd and this is why is why oem use maf and very rarely sd with lots of correction maps. THIS means you NEED tps correction especially if you use a big throttle body or a liniar opening throttle(a proggresive openig throttle is way better). you have to map this combo you have on the car on a load dyno , because you can't reproduce certain conditions on the road and only after you get a correct map (with 300-400 rpm and 0,1 bar, resolution at least in the problem area). a picture of your setup or a description would be great Quote Link to comment Share on other sites More sharing options...
Guest |580| Posted October 4, 2011 Report Share Posted October 4, 2011 My FPR is a sard unit. It is set to 60psi base and ramps up from there with boost. I will have to check the Deadband later this week. If I recall correctly, it's currently set to either 2% or 6%, but I'm not 100% on that. Quote Link to comment Share on other sites More sharing options...
Guest |823| Posted October 4, 2011 Report Share Posted October 4, 2011 You have quite a big base pressure, i would drop static pressure to 43.5psi (engine off, no vacum line , only pump runing)and increase fuel master so injector deadtime does not have such big impact on fueling( do you have correct injector dead time ?) what fuel pump, what is max boost? Quote Link to comment Share on other sites More sharing options...
Guest |580| Posted October 7, 2011 Report Share Posted October 7, 2011 Max boost so far is 18psi. Fuel pump is a Walbro 341. What's the method you use to determing the correct injector deadtime. I read a previous post in this thread describing the advantage of MAF systems for addressing specifically the problem that I'm having by providing higher resolution to tune with. While that may be true, my other vehicle a SC300 with a 1.5JZ (with upgraded injectors) and a powerFC that once exhibited this same issue no longer does (after changing injector delay settings). I believe that compared to the Vi-PEC the powerFC is a unit nowhere near as capable, but somehow was able to resolve this issue that is becoming one of my largest headaches on this car. Anyhoo... can you help me with information on determining injector deadtime? Secondly if this is not the equivalent to the PowerFC injector delay setting, what is? Quote Link to comment Share on other sites More sharing options...
Guest |955| Posted October 7, 2011 Report Share Posted October 7, 2011 Anyhoo... can you help me with information on determining injector deadtime? Secondly if this is not the equivalent to the PowerFC injector delay setting, what is? Do you have access to an oscilloscope? If you do, then I can try to remember where I found it, but there is a way to determine injector deadtime. I will start looking over the weekend for the article somewhere. Quote Link to comment Share on other sites More sharing options...
Guest |823| Posted October 7, 2011 Report Share Posted October 7, 2011 Max boost so far is 18psi. Fuel pump is a Walbro 341. What's the method you use to determing the correct injector deadtime. I read a previous post in this thread describing the advantage of MAF systems for addressing specifically the problem that I'm having by providing higher resolution to tune with. While that may be true, my other vehicle a SC300 with a 1.5JZ (with upgraded injectors) and a powerFC that once exhibited this same issue no longer does (after changing injector delay settings). I believe that compared to the Vi-PEC the powerFC is a unit nowhere near as capable, but somehow was able to resolve this issue that is becoming one of my largest headaches on this car. Anyhoo... can you help me with information on determining injector deadtime? Secondly if this is not the equivalent to the PowerFC injector delay setting, what is? injector delay = injectror dead time. injector lattency(=dead time=lag )is proper terminology. to detect deadtime you need injector with target pressure in fuel lines, oscilloscope and a knock sensor ......it's a bit too complex for home tuning, easy metod is to check miata forums where they use those injectors a lot with megasquirt. if not, easyest would be to switch to a injector with known dead time eg evo, sti, s14....on ebay you find them very cheap. as i said before base pressure is very high and that is why dead time has such big impact on fueling-lower it and it would be better if lower it a bit as you only use 18psi boost.... 3rd method for dead times ) :-in attached picture you have rx8 inj prymary and secondary deadtimes - is a 3d table rather than the standard 2d beacuse rx 8 has fuel pressure reg (fpr)in tank on the pump and no vacum line to fpr so it needs barro corection/what you vacum to fp does.... use values from 0.92 column(prymary injector-upper map) as a start and drop fuel pressure(43.5psi-no vac) for resolution-use bigger master Quote Link to comment Share on other sites More sharing options...
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