Bringing TBI and Multi Port Fuel Injection to a New Level.     EFI Conversions and Tuning! Seattle to Portland! E-mail Tuning Consultant!
Page 2 of 2 FirstFirst 12
Results 16 to 20 of 20

Thread: Considering Going to Open Loop Only - TBI

  1. #16
    Fuel Injected!
    Join Date
    May 2014
    Age
    36
    Posts
    24
    Open loop is the best way to go if You don't use catalic convetrer. CL is only to protect cat conv not to melt and work properly, all emission related. I run LT1 (92 and 95) OL, with ignition and VE finetuned (i'm MAF delete guy) i was able to get more MPG and power at the same time. CL is always targeting 14.7 AFR (except WOT situation) so you won't get bes overall performance and that limits MPG savings.

    best regards

  2. #17
    Fuel Injected!
    Join Date
    Apr 2017
    Posts
    69
    Quote Originally Posted by 1project2many View Post
    But your engine is not so radical that it should need these modifications. Think about a new driver who keeps stalling the truck when letting the clutch out on hills. The new driver blames the hills while the experienced driver sees it differently. You could set out to level all the hills but is that really the right approach?
    I agree, that’s why I’ve been frustrated. 383, Stock vortec heads, cam, valvetrain (except 1.6 ratio rockers, forgot to mention that) and 9.5:1 CR is not radical in my opinion so since I got it running I thought I’d be able to tune all the issues out, but haven’t succeeded yet. I still think I can get everything working right except one issue: the RPM oscillation during decel. That’s really the one issue that has given me the most frustration. OL makes it go away so that’s where I’m thinking of heading. However..... a few days ago my Moates AutoProm arrived and I do plan to dive back into tuning: learn how to use it, incorporate my Wideband data and start trying some different things. I’m wondering if I should try and get my VE table in better shape with WB in OL and then switch it over to CL after that and see where I’m at?

    The Autoprom arrived the day before we went on vacation so I didn’t get a chance to use it - won’t be till next week before I get to try it out.

    Thanks for the input, I do appreciate it.

  3. #18
    Fuel Injected!
    Join Date
    Apr 2017
    Posts
    69
    Quote Originally Posted by WASyL View Post
    Open loop is the best way to go if You don't use catalic convetrer. CL is only to protect cat conv not to melt and work properly, all emission related. I run LT1 (92 and 95) OL, with ignition and VE finetuned (i'm MAF delete guy) i was able to get more MPG and power at the same time. CL is always targeting 14.7 AFR (except WOT situation) so you won't get bes overall performance and that limits MPG savings.

    best regards
    Thanks for the input. So what about if there is a cat in the picture? Even though I could get away without in my part of WA state, I did decide to go with one - it’s a straight flow aftermarket type, low back pressure. Will running in OL fry my cat?

  4. #19
    Fuel Injected!
    Join Date
    May 2014
    Age
    36
    Posts
    24
    if You keep cats You should keep CL, CL fueling is mainly for keeping cats safe and opperatonal

    best regards

  5. #20
    Fuel Injected!
    Join Date
    Apr 2017
    Posts
    69
    Quote Originally Posted by WASyL View Post
    if You keep cats You should keep CL, CL fueling is mainly for keeping cats safe and opperatonal

    best regards
    Thanks, yeah, I think I'm backing away from my OL only plan. I have driveability issues with both CL and OL, but I think I can live with those on the CL side for now and keep plugging away with tuning to try and minimize them. I have my autoprom now (haven't had an opportunity to try it yet) so I'll be able to adjust parameters on the fly.

    And today I finally found the source of some of my driveability issues, both CL and OL. On the way home today it started idling and light accelerating poorly, which has been an intermittent problem recently. I opened the hood when I got home with engine idling and immediately saw a big blue arc at the plug boot of #3 plug wire. Obviously causing a significant miss. New Delco plug wire set on order already.

Similar Threads

  1. Open Loop EE Advice
    By spfautsch in forum GM EFI Systems
    Replies: 19
    Last Post: 06-03-2017, 01:13 PM
  2. Replies: 3
    Last Post: 09-06-2016, 07:06 AM
  3. Open loop afr
    By myburb in forum GM EFI Systems
    Replies: 10
    Last Post: 07-13-2016, 07:05 PM
  4. Open to closed loop
    By myburb in forum GM EFI Systems
    Replies: 0
    Last Post: 05-20-2016, 01:43 PM
  5. Open loop tune
    By bigtoyz in forum GM EFI Systems
    Replies: 0
    Last Post: 09-22-2015, 09:27 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •