Spec B Posted March 21, 2013 Share Posted March 21, 2013 Tuning a friend's 06 STI and I have run into a problem I can't figure out. Mods: Typhoon intake Invidia DP Cobb Exaust DW 1100cc sidefeed injectors Walboro Pump WB02 Basic Stage 2 setup with larger injectors. Installed the injectors and created a base map. Once warmed - the problem started, the idle would "bounce" between 650-850 and occasionally settle down perfectly for 10 seconds before starting to bounce around again. I naively thought I would work on the latency and get the fuel trims and the rest of the tune buttoned down and hopefully, the idle issue would work itself out. So I finalized the tune and the car runs perfectly, hits AFR targets perfectly and fuel trims are within 1-2% but the bouncing idle remains. At idle, AFR is bouncing between 14.5-15.4 and vacuum is -9.4-10.4. When it occasionally settles down for 10-20 seconds intervals, the AFR is 14.7-14.9 (much more stable) and vacuum is also stable and in the mid -10's. I should also note that while dialing in the injectors, I noticed that if the car idled incredibly rich (10.6 AFR), the bouncing idle issue went away, it would idle perfectly (although incredibly rich). Could these symptoms be a result of bad injectors? Vacuum leak? Anything else we should be looking at? Link to comment Share on other sites More sharing options...
GTTuner Posted March 21, 2013 Share Posted March 21, 2013 First, you cannot scale a MAF for an intake and determine proper latency at the same time. I suggest you install the OE air box (with the stock airbox MAF scaling) and tune your latency to within + or - 5%. Keep in mind the spec sheet from DW is a reference point and your latency will probably not be what the sheet says. My 740's had a latency spec of 1.14 and properly tuned the latency is .84ms (stock latency @14v was .68ms). So dial the latency and scaling in first, then you can throw the intake on and go from there. Second, if you pinched an O ring (the lower one) on a side feed it will run rich. So watch for that. Those injectors are awfull big for a relatively stock STi. I'm running an 18g on 740's and my WOT IDC is still less than 70% at 18.5 psi. I run a Typhoon also, it's a difficult intake to tune, or it was for me anyway. Link to comment Share on other sites More sharing options...
Spec B Posted March 21, 2013 Author Share Posted March 21, 2013 Thanks. I should mentioned it before - the only new parts added were the injectors and pump. Everything else was already installed and tuned for. So the maf scale was set while he was still on the stock injectors. I could probably work on the latency a little more - but I don't think it would cause such an erratic idle? The 1100's were in preparation to go bigger turbo on E85 in the future. Link to comment Share on other sites More sharing options...
GTTuner Posted March 22, 2013 Share Posted March 22, 2013 Ok so think of it systematicly....it ran fine before I did XXX to the car. Go back and go over what you did step by step. Get a fuel pressure gauge and make sure that pump isn't surging pressure....pull the injectors back out and make sure the o rings are OK. Put the old injectors in and see if it still does it. You're probably overlooking something simple! I don't think the latency would cause your issue either, it would run like shit all the time. I would log your MAF voltage when this is happening, maybe you have some type of post MAF leak. Maybe you shold log all the basics running well and running poorly and compare the results. Are you running the factory AF sensor in it's stock location still? I was thinking about the injector o rings.....I THINK it might have a hard start symptom restarting a warm engine if that were the case. A fuel pressure gauge would verify that. Link to comment Share on other sites More sharing options...
Spec B Posted March 22, 2013 Author Share Posted March 22, 2013 I wasn't there for the installation part - a good suby tech installed the injectors and then a few days later the pump. The problem started immediately after the injectors were installed. I will eyeball the install work, it looked ok to me, but your advice is solid...we should go over every step. Just did a LV - first one since we finalized the tune last week (I still need to make some tweaks to timing) and it showed +11% on the idle trim - could a leak be causing all this nonsense? Here is a log from a few moments ago. AFR is all over the place. romraiderlog_20130321_212828.csv Link to comment Share on other sites More sharing options...
GTTuner Posted March 22, 2013 Share Posted March 22, 2013 Gotta be something with the injectors, possibly a bad spray pattern on one IMO. Were the brand new or used? At any rate the side feeds are super easy to swap out just for test purposes. Looking at fuel trim, are you sure the FPR vacuum hose is on? Link to comment Share on other sites More sharing options...
Spec B Posted March 22, 2013 Author Share Posted March 22, 2013 Yeah..we checked all the vacuum lines and they looked fine and connected. i recommended he get leak/smoke test to rule out the issue all together. We also swapped the maf sensor, in the event it was causing the issue, no change. Injectors and pump are brand new. Once above idle speed, the injectors and the car performs as expected. I noticed his battery voltage a little low and that when a electrical load is added (headlights, rear defrost, wipers), the idle gets slightly better..almost perfect. Not sure how this is related, but wanted to mention it. Link to comment Share on other sites More sharing options...
GTTuner Posted March 22, 2013 Share Posted March 22, 2013 The battery voltage is good, pretty steady @ 13.8 volts however the IDC is all over the place, I'm not used to seeing that much of a swing idling and you can see the rpm flare correlates with the IDC increase and vice versa. My car idles very steady around 1.12ms ( or 1.21. I forget, but it is steady ) Log your car and see if the IDC is steady at idle. Does the wide band read close to what the calculated AFR is in your logs? I think if I were looking at this I would reinstall the stock injectors and send the DW back for testing if the problem is corrected on stock injectors. Link to comment Share on other sites More sharing options...
Spec B Posted March 22, 2013 Author Share Posted March 22, 2013 We will start with the injectors. Wbo2 and and stock sensor match pretty closely. Link to comment Share on other sites More sharing options...
GTTuner Posted March 22, 2013 Share Posted March 22, 2013 Did you see the swing in the IDC in your log? I think your gonna need to send those 1100's back for testing. Link to comment Share on other sites More sharing options...
Spec B Posted March 22, 2013 Author Share Posted March 22, 2013 I am starting to think the same thing - looks like bad injectors. Uggh. I will check my logs tonight - I doubt my IDCs swing at all. Link to comment Share on other sites More sharing options...
Spec B Posted March 22, 2013 Author Share Posted March 22, 2013 Here is a crappy video of the issue...gotta turn the speakers up. http://tinypic.com/r/35kinnl/6 Link to comment Share on other sites More sharing options...
GTTuner Posted March 23, 2013 Share Posted March 23, 2013 Update??? Link to comment Share on other sites More sharing options...
Spec B Posted March 23, 2013 Author Share Posted March 23, 2013 None yet - working on it tonight. My friend spoke to a few mechanics yesterday. Mechanic who installed the injectors says if there are no misfires or other issues, he doubts it is injectors...he is reluctant to go through the trouble of removing them. Another local suby shop thought it could be some kind of vacuum leak or the tune. Plan is to remove the intake and TMIC tonight and go over all the vacuum lines. I have never installed injectors myself, so I will leave that to the pros do that after we confirmed there are no leaks. Read a few threads on romraider that say to look for a post maf leak. Link to comment Share on other sites More sharing options...
Spec B Posted March 24, 2013 Author Share Posted March 24, 2013 Just finished a thorough check of all the vacuum lines and and the injector install one by one. We found nothing. The problem is getting weirder - we have discovered that the issue can be initiated at idle by adding load. For example, car started perfectly after we put it back together from our inspection. While idling perfectly I hit the defrost button to log - the unstable idle immediately began. Turned off the defrost, idle returned to normal. If I turn the steering wheel or if the radiator fans kick on, the lumpy idle returns. This is different than before - when it did it pretty much all the time. I think rules out the injectors as being the issue. At one point it idled perfectly for about 15-20 minutes until the radiator fans kicked in. Logs showing the effect of the defroster causing the idle and AFR correction to go crazy. romraiderlog_20130323_194155.csv romraiderlog_20130323_194215.csv Link to comment Share on other sites More sharing options...
apexi Posted March 24, 2013 Share Posted March 24, 2013 So it sounds like you're still using regular gasoline and haven't switched to e85 yet? I wonder if that's the problem, because when you go to the DW website they say "This injector was developed specifically for use with E85. Use of this injector with gasoline may result in less than ideal idle quality.". http://www.deatschwerks.com/products/fuel-injectors/sport-compact/subaru/sti/2004-06-sti/02j-00-1100-4-detail Link to comment Share on other sites More sharing options...
Spec B Posted March 24, 2013 Author Share Posted March 24, 2013 Hmmm. thanks. yeah still on pump, but i can't imagine the idle being this bad. My buddy planned on running E85 all the time, might make sense to try to tune it and see what happens. Link to comment Share on other sites More sharing options...
joeleodee Posted March 24, 2013 Share Posted March 24, 2013 I run this injector right now strictly on pump gas and it is no picnic dialing them in and living with them everyday. I've yet to tune them on e85 as that will occur once spring decides to show up in my area. That having been said, what tuning software is being used? What is your current injector scaling number? What is the bench flow of the injectors? What are your exact latencies? What is your idle speed/temp set at? I ask so I can compare your numbers with what has worked for me. As well, I had to make some MAF scaling adjustments here and there from known proper maf scaling before the injectors went in. A local tuner swears by ID injectors for higher flow necessities and the issues I have are due to just the nature of big sidefeeds, but I'm working with what I got. Mine will bounce consistently about 75-100 rpm which doesn't really bother me and they'll subtly surge under light load cruising. Link to comment Share on other sites More sharing options...
Spec B Posted March 24, 2013 Author Share Posted March 24, 2013 - Using Romraider - I set Flow to 1,100 (actual average flow is like 1,135) Latency: 6V - 7.34 9V: 2.58 12V:1.31 14V: 1 16V: 0.72 I ended up with higher latency numbers than expected - but AFRs are very consistent. Idle speed - I adjusted as high as 850 but the bouncing idle issue persisted, ended up back to stock (700 RPM). I was thinking of bringing it up to 1,000 just to see if the bouncing would stop. Glad to know the bouncing idle is not unique to my buddies setup, we have been chasing this issue all week. Link to comment Share on other sites More sharing options...
Spec B Posted March 24, 2013 Author Share Posted March 24, 2013 Please let me know what latency numbers you are running, I tried running less - but it required major MAF scale adjustment. Even after adjusting - the problem remained. We are switching to E85 later today, I will let everyone know how/if the problem was resolved. fingers crossed. Link to comment Share on other sites More sharing options...
joeleodee Posted March 24, 2013 Share Posted March 24, 2013 I have my idle set to 1050, actually. I've always had it set 300 over stock with these big injectors. My latencies when using romraider/OS tuning were as follows. 7v-2.22 9v-1.54 11v-1.21 14v-.95 17v-.7 My actual flow range on my set was 1204-1221 and my scaling number was 1085. It might be your scaling is a touch higher than it should be. Those values are different now since I'm tuning using Cobb StreetTuner, but the conversions would equal the same. Let me know how the switch to e85 goes as this info will aide when I switch over. Link to comment Share on other sites More sharing options...
Spec B Posted March 25, 2013 Author Share Posted March 25, 2013 Ok - set up the tune for E85 yesterday and the idle issue is still there, but much, much less pronounced. I raised the idle to 850 - and it is totally streetable, but pretty disappointing overall. My 850s idle just like stock, the 1100s are not that much larger - I am surprised that they do not idle better. As for the tune, I adjusted the injector scale 30% smaller (770 ish cc) - and that alone got all the trims within 5-7% - tweaked the maf slightly and finalized a rough tune. Target AFRs are in the 11.2 range in the top end and very, very consistent. I added some timing (2-3) degrees and the performance gain is impressive - even on this pretty rough tune. Link to comment Share on other sites More sharing options...
Spec B Posted March 25, 2013 Author Share Posted March 25, 2013 Any danger in damaging something by running rich at idle? Car idles perfectly at 12-13 AFR... Assuming it is safe to do - is there any way to do it without setting of system to rich CEL? Link to comment Share on other sites More sharing options...
joeleodee Posted March 25, 2013 Share Posted March 25, 2013 Any danger in damaging something by running rich at idle? Car idles perfectly at 12-13 AFR... Assuming it is safe to do - is there any way to do it without setting of system to rich CEL? You might burn through sensors quicker. I know I did when mine was running that rich at idle. It would throw the Cel every couple days. I'm still at work and on my phone, but look through threads I started and you'll see how that was resolved. The car had better driveability then, but too rich when idling. Of course with e85, that might be okay. I'll be able to get more detailed later tonight when I'm home from work if you're interested. Link to comment Share on other sites More sharing options...
Spec B Posted March 25, 2013 Author Share Posted March 25, 2013 Cool - Thanks. There are no noticeable drivability issues after the conversion to E85 - Just the lingering idle issue. I wonder if there is a way to disable the to rich code from popping up. Link to comment Share on other sites More sharing options...
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