CamH Posted December 9, 2009 Share Posted December 9, 2009 I have been running a set of DSM 450CC Injectors (blue top) for the last couple of weeks. I have been having issues with AFRs around my boost threshold at freeway speeds. (2500-3000RPM in 5th while cruising) I did not have this problem with my old 280ZX Turbo injectors. No matter how low I edit my VE table, I cannot get my AFRs to go above approximately 10, however they will momentarily jump above 10 (maybe up 11 or 12, but, really all over the board). This makes the car "surge" (wanting to accelerate, then falling on its face momentarily) Also, if I am accelerating hard through it, I will sometimes get backfires (I have been avoiding accelerating hard due to this reason) Another thing, I posted this in the Injector thread, but it may possibly be related: I have a question about the settings for the 450CC DSM injectors. I know what you state in the spread sheet, but there is some other information floating around for those injectors as well. Namely: http://forums.hybridz.org/showthread.php?p=562900 The part I am most interested in is that the other thread states the following: PWM current limit % 100 PWM Time threshold (ms) 25.5 Which does not at all match the spread sheet. Which settings should I trust? I am using the factory L28ET RRFPR still. Could this be causing issues by forcing more fuel in by momentarily jumping up the fuel pressure, and possibly dropping back down? Should I try to rectify the issue by capping off the vacuum reference ports for the RRFPR? Thanks for any help I can provide some datalogs and numerous "testing" MSQ files as examples this afternoon. I just wanted to see if I could get some ideas during the day. Quote Link to comment Share on other sites More sharing options...
S130Z Posted December 10, 2009 Share Posted December 10, 2009 Are they high impendance injectors or low impendance? Quote Link to comment Share on other sites More sharing options...
CamH Posted December 10, 2009 Author Share Posted December 10, 2009 z-ya posted that the 100%/25.5ms settings were if I was using a resistor pack, which I am not. So I was using the correct injector settings from his table all along. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted December 10, 2009 Share Posted December 10, 2009 Datalog it. There are so many things that could be set up wrong that's where I'd start. FWIW, I'm running the Ford 440cc injectors with a T3/T4 and don't have this issue, so suspect it's not the injectors, rather something in your tune. BTW, I have to ask a basic question. You said these injectors replaced the stock ones. Did you change req fuel? If not, that would explain why you can't get the AFR above 10 Quote Link to comment Share on other sites More sharing options...
CamH Posted December 11, 2009 Author Share Posted December 11, 2009 BTW, I have to ask a basic question. You said these injectors replaced the stock ones. Did you change req fuel? If not, that would explain why you can't get the AFR above 10 You are so right! I made this change this morning, and it seemed to help quite a bit. I reset my VE table to a more "sane" setting (I actually copied someone's VE table from the MSQ sharing thread) and it has almost completely solved the surging issue. However, I am still getting some slight backfiring. I'll post the MSQ and log this afternoon when I get home from work to see if I can get some additional good advice. Quote Link to comment Share on other sites More sharing options...
CamH Posted December 12, 2009 Author Share Posted December 12, 2009 Alright, here is the MSQ and datalog if someone feels like taking a look at it. http://henlin.org/msq&msl.zip Quote Link to comment Share on other sites More sharing options...
S130Z Posted December 12, 2009 Share Posted December 12, 2009 Hey Cam, Try setting your minimun accell enrichment on the TPS side at 100kpa/s and see if that helps with anything else. Did you try playing with your accel enrich after changing your injectors? Quote Link to comment Share on other sites More sharing options...
CamH Posted December 12, 2009 Author Share Posted December 12, 2009 Hey Cam, Try setting your minimun accell enrichment on the TPS side at 100kpa/s and see if that helps with anything else. Did you try playing with your accel enrich after changing your injectors? Hey, yeah I copied cygnusx's (I think) accel settings who has similarly sized injectors. I will give that a shot the next time I take it for a drive, but I'm kind of curious as to how you came up with that. Would you mind explaining your reasoning so I can get a better understanding? Quote Link to comment Share on other sites More sharing options...
niner11 Posted December 12, 2009 Share Posted December 12, 2009 I think that I have the same injectors running on my T3/T4oe 280zxt motor. I've just posted it in the MSQ thread, let me know if it works out for you. Quote Link to comment Share on other sites More sharing options...
S130Z Posted December 12, 2009 Share Posted December 12, 2009 Also, if your were running 10:1 for a while, change your spark plugs. I hit 10:1 for the first time the other day and I fould all my plugs out. Also, if you havent tried it before, try side gapping them. If you do, let me know the results. As for the accel enrich. In the tunning section of the MegaManual, it says to start with your lowest value of 100kpa/s. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted December 12, 2009 Share Posted December 12, 2009 You still have req fuel at 8.2 which is high for those large injectors. As a point of reference, with 440cc injectors I'm running req fuel = 3.0. Of course, this increases the range of values for the VE table. If you want to start from scratch, use the req fuel calculator in MT. For a stock block and 280 cc turbo injectors you'll get 11.0 ms. Do it with 450 cc and you'll get 6.8 ms. I cut it down further to expand the range of values in the VE table to above 100. I'd suggest you go back to your last good msq file from when you ran the stock injectors and scale (multiply) whatever you had for req fuel by 0.62 (=280/450) and start over. If you had a decent tune with the old injectors, and the new injectors have a similar opening time, then you shouldn't see much difference in the AFRs with the new injectors. Also, have you tried datalogging and then using MLV to tune? It looks like you need to take a few long drives while logging, and after each one, run MLV and let it recommend changes. If you haven't been using this tool, you're doing it the hard way. Quote Link to comment Share on other sites More sharing options...
S130Z Posted December 12, 2009 Share Posted December 12, 2009 I am running 440cc injectors with a required fuel @ 7.1 and have had no problem with dialing in my VE tables. Although this idea of lowering it really makes me want to give it a shot for a more accurate table. I have notived how sensitive my VE table is though. Maybe when I get back from my cruise in a week I will take a day or two off and make a new table. Cam, If you try this before I post results, let me know how it goes for you. Quote Link to comment Share on other sites More sharing options...
CamH Posted December 12, 2009 Author Share Posted December 12, 2009 OK, guys, it looks like I have a lot of different stuff to try on my next drive. Thanks for the advice everyone. I'll post another MSQ and log after my next drive Quote Link to comment Share on other sites More sharing options...
Zmanco Posted December 12, 2009 Share Posted December 12, 2009 A suggestion: hit the space bar on the laptop while datalogging to mark the event. That makes finding it a lot easier when you're reviewing. You can give us the time code from the bottom of the screen so we can find it too. Quote Link to comment Share on other sites More sharing options...
CamH Posted December 19, 2009 Author Share Posted December 19, 2009 Hey, guys, just an update: I think a part of my problem was that one of the injectors I got was junk. I swapped them out for a new set of RC Engineering PL9-550 550CC injectors and the car runs much better! It pulls extremely hard with no backfiring or anything. New turbocharger is going on very soon now. Quote Link to comment Share on other sites More sharing options...
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