PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

WTF this is driving me banannas

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Old Oct 12, 2004 | 07:48 PM
  #1  
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Default WTF this is driving me banannas

I am still having a part throttle hesitation and the LTRIMS/STRIMS are going whacked.

Here is what I have done to see what is happening:

1) smooth bellows in place of MAF (To see exactly what the LTRIMS and STRIMS are doing)
2) ATAP logging MAF, timing, LTRIM, STRIM, O2B1S1, O2B2S1, cell, MAP, KR etc.

At light cruise under 2500rpms my LTRIMS are at -10.8 but the STRIMS are at some ridiculous number (-28!)

I am getting tip in hesitation and other weird ***** happening.

At part throttle under 3000rpm the LTRIMS are -2 to zero and at 3/4s throttle it jumps up to zero to +2

At full throttle the LTRIMS and STRIMS are perfect zeros across the board and the car pulls like mad above 3000rpm.

Driveability wise is pretty much the same with the MAF plugged in versus unplugged with the smooth bellows.

I am throwing a slow switching O2 code on bank 1.

WTF can I do about this? I have to drive to the dyno to get LS1edit work done on the car at the moment while I wait for the focking HPTUNERS with wideband to be completed.

Anyone have any ideas for me?

What will happen if I unplug the O2's??

Will it default to full SD mode and run rich/safe at part throttle??

I dont give a **** if I get 12mpg as long as the driveability is decent and WOT performance unaffected.

Car is running GREAT at the track but around town it is irritating....

Can I do a quick and dirty part throttle SD tune on the dyno (keep it at 13:1 or so at cruise, tip-in and WOT?) Copy the High Octane timing table into the Low octane table and tune it for WOT?

Help appreciated, I am going nucking futs...

Thanks,
Chris

ps- Here is the combo

385 stroker
LS6 ported heads (327cfm at .600 lift)
236/242 110LSA cam (XER lobes)
stock MAF, stock throttle body (ported) stock LS6 intake
dual cats (ORY coming soon)
1 3/4 to 1 7/8 edelbrock headers with slip fit collectors (Few very small leaks which is probably focking things up more)

HELP!
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Old Oct 12, 2004 | 08:02 PM
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Looks like you are running way rich. If you had HPTuners this would be worlds easier sinceit tabulates and averages all data . You are gonna need some more work on your secondary ve table averaging the trims at those rpms and map values (lots of work trust me I know ). If you unplug the o2 sensors and your ve table isnt correct you can be either running real rich (worse hesitation) or real lean because in open loop your open loop fuel air table is nothing but a divisor of 14.7/1.13 should be 13.0:1 IF THE VE TABLE IS ACCURATE.


Until you get that ve table dialed in you will have problems. How are you tabulating and averaging the data? This may be where you are having the most problems?
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Old Oct 12, 2004 | 08:15 PM
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Do you think I should just go ahead and buy HP tuners and not wait till the wideband option is available?

What would happen if I swap back in stock 98 injectors, stock 98 IFR values and stock VE values and go from scratch on the PE/RPM tuning?

(I am at 46XRWHP and ~44X RWTQ through a heavy drivetrain - 12 bolt, heavy DS and heavy clutch)

Would I be maxing out my stock injectors?

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Old Oct 12, 2004 | 08:34 PM
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Have you allready purchased a stand alone WB unit. If not I would buy HPTuners now. The WB option you speak of still requires a stand alone unit, they just offer the capability to merge the data stream from an independant source...

I wouldnt get into changing to much things...

How did you come about the IFR table for your current injectors and what size are they?

How computer savy are you? Have any experience with MS Access? if not i can walk you through a time consuming excersize that will help you tabulate the data. Actually it is a repetatvie command/query used to help with the data. Once you get the hag of it, it will be real easy depends on how much patience you have

I would start with the stock ve table. Initially i will be really lean so you WILL see + trims but this is ok because you wont be beating on it and the o2 feedback will take of that via trims.


IM me on aim at lhas9978 or msn lhas9978@hotmail.com


Edit leave the ve table alone. We will start from there since you allready have data using the current table
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Old Oct 12, 2004 | 08:52 PM
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I'm guessing you have bigger than stock injectors.

Normally bigger Cams like yours like more timing at part throttle which will also affect A/F readings. Also if your MA is unscreened it can give funky part throttle L-terms.
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Old Oct 12, 2004 | 09:14 PM
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I think he has the ultimate descreened MAF - a piece
of hose.

If you pull O2s then you will be full time open loop. I
think then you will get your mixture commanded by the
Open Loop Fuel Air table, so that would want to be
kinda right (probably is, at least at low MAP). The
clow O2s may be doing you more harm than good,
tend to push you rich as the low "asleep" voltage
looks like lean. If you pull the O2s of course then you
can't look at them... but if you could plug the fronts
into the back O2 harnesses then you can datalog them,
and tweak VE to get O2 voltages (presuming they are
lit) of 300-600mV and call it good. You might have to
"clear its throat" every so often to get them hot, I
guess; but should not take too long to get idle sorted.

If you sort of home in on it like a binary search and
keep track of where you've been you can probably get
fairly close in a few flashes.
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Old Oct 12, 2004 | 10:04 PM
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Jimmy. offtopic how come your name appears in green at times?
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Old Oct 13, 2004 | 08:46 AM
  #8  
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Originally Posted by HumpinSS
Jimmy. offtopic how come your name appears in green at times?
Because I'm part of the New User section moderator
tag-team.
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