Results 1 to 13 of 13

Thread: RAMJET - OTR. MAF Lean - Solved. Opinion

  1. #1
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767

    RAMJET - OTR. MAF Lean - Solved. Opinion

    I bought a RAMJet OTR. A wideband.... dialed it all in...... for months now i've been trying to solve a very odd leaning out issue which is primarily when the car is hot and off throttle....... it leans out to til 25+ ...... MAF or VE ..... or Transient compensation never fixed it..

    Anyway ...... So I have a question as I think I found the problem. I had a transmission cooler where the OTR now is but.... I moved it to the lower part of the front of the bay....... but infront of the OTR filter.... is a loop of metal pipes which run down to the transmission cooler.

    My thoughts are...... The heat of those pipes sitting directly infront of the OTR is throwing the maf out off throttle....

    What do you guys recon? .... there's quite a bunch of bent loopy pipes there, I will take a photo when I get home.... I just want to confirm this before I go about fixing it.....

    air/fuel ratio's are right etc........ I looked at other peoples tunes with OTR's they just have done maf etc...... like me, i'm the only one with this problem but i'm the only one with these stupid transmission cooler pipes right infront of it.....

    You guys recon thats my issue?

  2. #2
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    Nup doubt it's it...... no particular map, throttle or temp seems to do it...... crap. Tune and Scan Posted.
    Last edited by BigDaddyCool; 11-21-2012 at 03:59 AM.

  3. #3
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    Alright, well...... after spending 6 months attempting to fix my issue..... (reverted back to the stock box for a while) ..... at long last i'm onto the solution...... after reading a lot.

    Need to mess with the o2 mv gear...... so it switches faster.... Dropped them from about 450 to 43.... Trying different combinations...... helps a lot. At the moment I'm a tad rich in area's, lean in others....

    I'll have to mess around with the proportional etc..... What surprises me, the Greg Banish DVD's didn't really go into this when turning a intake change with a wideband.....

  4. #4
    Senior Tuner eficalibrator's Avatar
    Join Date
    Mar 2006
    Location
    Detroit
    Posts
    1,023
    Quote Originally Posted by BigDaddyCool View Post
    What surprises me, the Greg Banish DVD's didn't really go into this when turning a intake change with a wideband.....
    That's because I have a few rules about how I go about this:

    1) I don't trust aging narrowband O2 sensors when I have a laboratory grade wideband right in front of me that I just calibrated.
    2) I try to keep the IAT in the same relative location as stock. There's a charge temp bias model that adjusts the effective charge temp based on heating from the manifold that ASSumes the IAT sensor is in the stock location. If you move the IAT sensor, you probably need to readjust the bias model.
    3) You MUST have correct injector data before using wideband error to solve for MAF or SD airflow numbers/corrections. Otherwise, you bake errors in that change significantly with temperature.
    4) A MAF sensor doesn't care about ambient temperature. I like using these and often do this part of the calibration first as long as there isn't a ton of reversion skewing the numbers. Just make sure it has a clean, consistent signal.

  5. #5
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    Yes no my problem still exists....... there is a reversion table thats 0'd out...... i haven't played with that.

  6. #6
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    TOTAL FAIL........... Went out with the wideband today MAF tuning........ still does the same BS to the wideband as it does with the narrowbands....

    Surges upto around 1.26 lambda on the wideband off throttle.... messed around with the manifold vaccume reversion gear no change.... so i dunno.... stuck. next stop will be transient fueling i guess.....

    Anyway see my attached wideband log...

  7. #7
    You really need to post a copy of your tune before anyone can offer much help.
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  8. #8
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    My problem with posting tunes is it gives people essentially your knowledge on alot of other things........... I will post it, atleast you have a SSV..... I seem to be the only person who has this issue..... and it's really peeving me off..... and I've done maf tuning before on another car with a wideband and never had these issues..... mind u that was a cai not otr.

    The tune attached is the one used while maf tuning with the wideband....
    Last edited by BigDaddyCool; 11-24-2012 at 06:20 AM.

  9. #9
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    It's such an odd issue... It's like the maf drops off to really low readings and the o2's seem to get stuck or run super slow? ........ eg. maf drops down.... eg. 600-1200 rpm ranges, o2's drop to around say 9-60mv... and stick, it leans right out and then all of a sudden after like leaning out to about 20+ say... starts working again...... so weird. It does it throughout the entire rev range...... mostly while driving..... as opposed to park etc.

  10. #10
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    I would love like some idea's to try.... not one person on this forum has helped me on this issue in 6 months.... so i think from now on, anyone pm'ing me...... asking me advice, i'm done

  11. #11
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    I half wonder if it's just that the ramjet has the pvc hole cut out on the wrong side....... all the other otr's have it on the same side as the stock intake........

    makes more sense considering the wires are also on that side of the maf.... I'm gunna try compensating with VE.....

  12. #12
    I'm no expert but it looks to me like the issue is mostly at very low air flows and throttle positions, it looks like its when your VE and MAF dont agree, you could try rotating you MAF to see if that helps or try an air straightener but at the end of the day it just looks like a good example of why GM uses a blend of VE and MAF that heavily bias the VE at low air flows and engine speeds rather than pure MAF.

    Someone has posted an issue the same as this before, I remember looking at the logs with the same behaviour but I cant remember the title or who posted it.
    Last edited by Xjas; 11-26-2012 at 03:11 AM.
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  13. #13
    Advanced Tuner BigDaddyCool's Avatar
    Join Date
    May 2009
    Location
    Brisbane, Queensland
    Posts
    767
    yeh i had the same idea..... but tuning ve is alot harder without a dyno......

    It's a bit of a bugger really, because messing around with VE especially in the idle zone half the time makes idle horrible....... I think this coming weekend I will try 'retuning' but just doing the VE........ then I'll monitor for week.