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Thread: Tuning help needed - '91 TBI 383 w/ Vortec heads

  1. #46
    Fuel Injected!
    Join Date
    Jan 2017
    Posts
    190
    Quote Originally Posted by donf View Post
    Sounds like a good plan. I use to work in front of a machine shop. I had to do their R&R's sometimes when things went wrong. The big thing that got them over and over was hone grit. They would get in a hurry and just hone it with what ever they thought was standard. Different brands and ring types will tell you what grit to hone the cylinders. As far as beating on it, vs not I really don't think that makes the difference compared to having a machinist who reads and follows the ring manufactures instructions. Some cylinder pressure behind the rings though will push them out against the walls harder. I do think if your rings have not fully seated, switching to conventional oil may help. It doesn't even have to be the good stuff if you do not have a flat tappet cam. If it does, one with zinc will help.
    What he said to seat rings...wind it up and let the compression slow the vehicle down repeat like a dozen or so times.
    Last edited by stew86MCSS396; 2 Days Ago at 07:41 PM.

  2. #47
    Fuel Injected!
    Join Date
    Apr 2017
    Posts
    39
    Quote Originally Posted by stew86MCSS396 View Post
    What he said to seat rings...wind it up and let the compression slow the vehicle down repeat like a dozen or so times.
    Switched to Rotella T4 (conventional) over the weekend. We'll see what happens. Back to tuning.

    I like the idea of winding it up and using compression to slow it down to seat the rings but there's a problem......that's where I have my worst tuning problems. After oil change I took it on a home depot run and it ran great until I came off the freeway on a downhill ramp. I dropped it down twice, when I hit second it went up to about 3000 and I started getting some popping/light backfiring out the tailpipe. And it seems like after that event happens, my idle gets messed up. 100-200 higher than commanded and some hunting with a range of about +/- 75 rpm. Then after an engine stop and restart, it seems to be back to normal, idling at commanded speed and no hunting. I have only seen that behavior a few times though so I don't know if it's consistent.

    I've been shopping for a WB kit. Suggestions? I'll probably just go with a typical AEM kit with gauge and sensor. How does logging work with a kit like this? Sorry for the dumb questions, but does data go through my ECM (extra channels?) or does it go directly to my laptop/tuner pro and then logged simultaneously? I've read some threads on the former method and it seems like that may be out of my league. Or maybe I should forego simultaneous logging altogether to keep it simple? Again, if it sounds like I don't have a clue what I'm doing, it's because I don't! Is there a WB tuning for dummies thread that someone could point me to?

  3. #48
    Fuel Injected!
    Join Date
    Apr 2017
    Location
    Oregon
    Posts
    166
    Popping out the tail pipe is rich, not unusual, I had to take some fuel out there too but I only have 19.5 psi. I think it will be especially bad if you have the fuel pressure jacked way up to almost 30 lbs. That is why I don't like to run any higher fuel pressure than really necessary as there is a trade off sometimes in transitions not being as clean. Hopefully you can work it out by adjusting the VE table more. I like the AEM X-series that has some improvements over the older version you linked to. I use the wide band sensor in that series, you have to redo the math, but its fairly easy.

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