Install LT-1 and Translator

Discussion in 'All Topics, Chips, and Tech for Buicks' started by Tom Kelly, May 3, 2019.

  1. Tom Kelly

    Tom Kelly Active Member

    I just got my LT-1 MAF and translator. Before I get started I have just a few questions. I see that there are three settings for lean/rich at idle. I am guessing that these will come into play after the ecm has “relearned” long term fuel trim. My current BLM is around 135. Will changing to the new MAF sensor have a predictable effect on BLM or is every car different? Also, how far from 128 does it need to be before I fuss with the settings to bring it up or down?

    Also, as to the WOT settings for fuel. Can I assume that I should leave this as O – no change and continue to use my turbotweak 5.7 chip and scanmaster to make my WOT fuel adjustments or is there some advantage to using the translator for changes?

    Thanks for providing the parts and service that helps us all with our GN’s

  2. EricM

    EricM Administrator Staff Member

    Once you get it installed and reset the ECM, drive around a let the BLM's learn. If the idle BLM is more than 8-10 numbers higher or lower than 128, then you can use the MAF base "richer" or "leaner" to get it closer to 128.
    WOT should normally stay at zero for the 5.7 chip, and use the WOT parameter in the chip to adjust if necessary.
  3. Tom Kelly

    Tom Kelly Active Member

    Eric, installed the new LT-1 and translator. Old hose will not reach as the LT-1 is shorter than stock MAF. Need to over about five inches. Do any of your adaptor hoses do the trick? I have a 3" pipe.
    Also, got the scanmaster 2.2 working. Two questions. 1. Scanmaster shows A/F reading higher (by about 2 full numbers) than the AEM gauge. Both connected to the same wideband sensor so what would that be from?
    Also no "Bst" reading on scanmaster although MAP sensor connected to it. I had thought MAP sensor was a 3 bar unit installed by previous owner. If it is a stok MAP sensor would that be why not betting Bst reading? Also wondering what "E" = 32 is on scanmasster..
  4. Tom Kelly

    Tom Kelly Active Member

    Got the boost reading correctly on the scanmaster now and figured out that "E" is EGT. Only remaining issue is why AEM gauge and scanmaster are showing different A/F numbers (Scanmaster 2 full numbers leaner). Also still wondering if you have a hose adapter that will stretch to accommodate the shorter MAF. Thanks
  5. EricM

    EricM Administrator Staff Member

    Make sure you set the type of wideband in the powerlogger software while connected to the ECM.

    I do not have any 3" to 3" hose couplers, only adapters.
  6. Tom Kelly

    Tom Kelly Active Member

    Thank you. I will set it for AEM gauge 1-5. I am almost there. thanks for your help. Tom
  7. EricM

    EricM Administrator Staff Member

    It depends on which AEM you have, there are 2 settings in the software, but you can try both to see which one makes it match up.
  8. Tom Kelly

    Tom Kelly Active Member

    Yes I now see the other one (Inline) I have the X-series sensor and gauge I bought from your shop.
    ShaunKris likes this.
  9. EricM

    EricM Administrator Staff Member

    Ok, yes the X-series uses the "inline" setting.
    ShaunKris likes this.
  10. Tom Kelly

    Tom Kelly Active Member

    Good tip! Thanks again,
  11. Tom Kelly

    Tom Kelly Active Member

    Hi Eric,

    Finally got the right length 3” hose for the new LT-1 MAF and it is now installed along with the translator. I noticed a couple of things.

    My 86 has always idled perfectly. So perfectly you couldn’t see any movement at idle. Perhaps this is at least partially due to the expert balancing during the rebuild. Anyway, A/F ratio at idle was pretty consistent at about 13.6-13.7. I have read in other posts that the turbotweak chip does this intentionally (a bit rich). Also, long-term fuel trim was always at about 137.

    After installing the new MAF and translator, (set to the neutral settings) it ran a bit rough. I figured that the roughness might be the ecu getting used to the new MAF after being reset. But the roughness continued and the long term trim was showing about 142. Idle A/F was now showing about 14.5-14.7.

    So I used the translator’s adjustment to enrichen at idle and the idle smoothed right out and after a short ride the long term trim is already down to 137. I suspect it will continue to decrease over time.

    However the idle A/F is still at 14.5-14.7. Not a problem as it is idling perfectly but wondering if that is a normal outcome from switching to the LT-1.

    Also, selected “AEM inline” and now the gauge and scanmaster agree. Thanks for that tip. Tom
  12. EricM

    EricM Administrator Staff Member

    Did you set the Translator for the LT1 MAF?
  13. Tom Kelly

    Tom Kelly Active Member

    Yes. Initially at “neutral” (3) but moved to setting “4” to get the long term trim closer to 128.
  14. EricM

    EricM Administrator Staff Member

    Ok. Normally I reset the ECM when changing Translator settings so it can relearn from scratch, but it's not a big deal. Once everything has learned, I normally expect idle AFR around 13.5 give or take, when it goes into open loop idle mode.
    ShaunKris likes this.
  15. Tom Kelly

    Tom Kelly Active Member

    I understand what you’re saying. I’ll give it some time. As I said it’s idling perfectly. I was just wondering about the change in A/F. Thanks again.
  16. Tom Kelly

    Tom Kelly Active Member

    Hi Eric

    I took your advice today and reset the ECU to get things started fresh. I noted a few things.

    A/F ratio at idle continues to hover between 14.6-15.2. Under normal (careful) driving around town (under 40 mph) it rarely goes below 14.7 and actually hangs out right about there. Rapid acceleration, not WOT but brisk, can bring it down to 10’s briefly. So gauge is working. Scanmaster now agrees with gauge exactly.

    Important: Unlike how it was before, idle seems stuck in closed loop (dot on scanmaster not flashing as it used to) This is after a fresh reset.

    The scanmaster 2.2 has two additional readings that I don’t know. Perhaps you could enlighten me please:

    1. After cc there is something that looks like Pw which moves between 1.0 and 2.1

    2. Then comes Sp which moves between 26.4 and 27.1

    Additional information

    Bst (vacuum) is a healthy 19

    E (EGT) stays at 32. Is there no stock input for this? I suspect not.

    No MAL codes.

    Car runs fine. Smooth idle and crisp throttle response.


  17. Tom Kelly

    Tom Kelly Active Member

    I forgot to mention that long term trim jumped right up from 128 at the fresh start to 142. this is with the translator pin set to be rich at idle (4) With the old MAF it used to hover around 135-137
  18. EricM

    EricM Administrator Staff Member

    On a fresh reset, open loop idle is not enabled the first time you run it, so that's normal.
    PW is injector pulsewidth, and SP is spark advance. There is no input for EGT, so you can turn it off in the powerlogger software under scanmaster options.

    The BLM is not a huge concern. However, since it's been on the higher side with the old and new MAF, there might be something causing it, like fuel pressure is actually lower than what your gauge says, or your PCV is leaking air through (or if you have one of those check valves instead of PCV), or some other vacuum leak. But if the car is running fine, there's no particular reason to mess with it.
    ShaunKris likes this.
  19. Tom Kelly

    Tom Kelly Active Member

    Once again. Thank you.
  20. Tom Kelly

    Tom Kelly Active Member

    You are very experienced obviously. I followed up on your suggestion of a vacuum leak. Rather than look at everything I tested the cruise control and the air conditioner (the part where you can control outlet) and both were inoperative. Bingo. So I traced the vacuum line to a gang connection near the intake and sure enough, one of the temporary plugs (we’re troubleshooting the boost gauge) must have fallen out.

    With vacuum leak solved and after a brief spin around the neighborhood, BLM fell to 126 which is consistent with old readings and the “enrichen” switch on the translator being selected.

    So now about A/F in idle. Here is what is going on. Idle in neutral continues to be just about and a little higher than 14.7. Putting it in gear (or turning on the A/C) instantly lower A/F to 13.9. Normal? If so, I am ready to start tuning. Just recorded two runs on the highway to get the feel of it. Incredible tool. Looking forward to tuning out the knock and getting the maximum boost.


    p.s. If your weather today is like Connecticut, you are forgiven for not monitoring your forum on a beautiful day like this.

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