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Thread: Unusual idle occurance after injector replacement/IFR adjustment

  1. #11
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    Quote Originally Posted by Thumper View Post
    Sorry to hijack, but i have a noob question.
    Why is your MAP pressure so high at idle? My logs show around 55-60 KPa at Idle for my car. What would cause this difference?
    Low idle speed + 112LSA cam = less vacuum present in the manifold during idle would be my asumption.
    Dave
    -'07 Acura TL Type-S
    -'07 Honda Ridgeline RTS
    -'00 Pontiac Trans Am WS6

  2. #12
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    Quote Originally Posted by jfpilla View Post
    xxxxxxYou have a wideband, tune it properly. VEs have an impact under
    4000rpms in assisting fueling when the maf can't handle it.

    Alright, i'm gonna go ahead and work with the VE map in the idle area and see what kind of results I get. I'm also going to go ahead and perform an 'AutoVE' run through since I noticed on an extended cruise that my LTFT's were maxing at 25% indicating my map must be especially off. Thanks for the input thus far!
    Dave
    -'07 Acura TL Type-S
    -'07 Honda Ridgeline RTS
    -'00 Pontiac Trans Am WS6

  3. #13
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    Quote Originally Posted by VTC_WS6 View Post
    Low idle speed + 112LSA cam = less vacuum present in the manifold during idle would be my asumption.
    I have a cam with a 114lsa. My manifold pressure is lower than the posted log.
    Just intereseted to know.
    VX commodore, Promagum 1.75:1, 216/220 114 cam Comp 915 springs. Attempting to tune

  4. #14
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    **PROGRESS!!**

    I know I'm fielding my own audience here but I'm too happy to see some kind of progress to keep it to myself!

    So after taking in some of the advice I've recived in this thread I decided to go ahead and take a few 'blind' stabs at a few different calibration properties and see what kind of results they deliver. As of right now I'm still stuck with two main concerns, first is a major lean surge during initial startup, and second it the surging and hesitating while driving accompanied by a maxed out 25% LTFT. Basically anytime the PCM would deliver less than 25% additional fuel in correction to the commanded the car would buck and surge and I'd see the AFR swing wildly lean.

    Attempt 1: Add 25% to Main and Backup VE maps.
    Result: Initially the startup lean surge was delayed compared to previous logs, but it still ended up at 20+ AFR till the vehicle went CL and the O2's slowly brought it back to normal AFR. Same thing while driving, lots of bucking anytime the LTFT would drop from 25% accompanied by a major lean spike. Failure.

    Attempt 2: Add an additional 15% to Main and Backup VE maps.
    Result: This was performed as an 'off the side off the road' update so I don't have any cold idle logs, but initial startup was still extremley lean till the O2's kicked in, driving was no different with lots of bucking whenever I'd enter a new part of the map and LTFT's droped as the AFR would rocket up to 20+. Failure.

    I then got the bright idea to trace some steps. The only real change to the map of note since I installed the injectors has been the IFR table and now the VE maps which yeilded little to no change in outcome.. what if I was chasing the wrong tail? I immedaitley pulled off and shut her down, switched over to the calibration and dropped the IFR rate figuring if such an increase in VE yielded no increase in stable fueling, maybe i'm starting with less fuel than I thought?

    Attempt 3: I reduced the IFR some 15% and reloaded the PCM.
    Result: Initial startup keeps the AFR 'normal' for a few more seconds but still goes to 20+ untill the O2's come into play, I do notice the car then idles at normal AFR with only 20% LTFT. Take it for a drive and I FINALLY see some results! Bucking is virtually gone, LTFT's are hanging in the mid-teens with steady AFR readings, alas I'm getting somewhere.

    This leads me to two conclusions. First, I either way over calculated my IFR numbers, or I don't actually have 42# injectors, and second, my VE map may not be nearly as off as I though. Either way i'll put some more tinkering into it tomorrow, drop the IFR some more and start a little more logging to see of I can't get it down to where I need it. Either way I'm just glad to finally see the light at the end of the tunnel. And big thanks to you guys for helping!
    Attached Files Attached Files
    Dave
    -'07 Acura TL Type-S
    -'07 Honda Ridgeline RTS
    -'00 Pontiac Trans Am WS6

  5. #15
    Lifetime Member hquick's Avatar
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    From what I understand....decreasing the IFR richens everything globally. Alot of tuners use this method.
    Howard

    YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
    MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
    DUCT TAPE.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.


    98 K1500 'HOLDEN' Suburban.
    Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit

  6. #16
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    Quote Originally Posted by hquick View Post
    From what I understand....decreasing the IFR richens everything globally. Alot of tuners use this method.
    That's basically what I was counting on. In my case I deduced that because I was making what I belive to be rather large changes to VE with zero results, maybe my IFR was off to begin with, causing the PCM to run max increase (LTFT) to keep the AFR's where commanded.
    Dave
    -'07 Acura TL Type-S
    -'07 Honda Ridgeline RTS
    -'00 Pontiac Trans Am WS6

  7. #17
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    I'm glad to hear you're making progress. Keep us posted.
    2000 Camaro SS Convertible
    M6,
    LTs, AFR 205s, Comp xer 220/224, LS6 intake, Ported TB, AR TT IIs

  8. #18
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    Well I did a little more tinkering today but no breakthroughs. I'm glad SD and TAQuickness have shared some info latley how basic tune ideas and fundamentals because I think i'm at the point where I'm going to revert to either a true stock tune and work up from there or at least go back to my tune before the injectors were installed and go from there.

    I dropped the IFR about another 5% and as expected I saw the LTFT drop even further, but what bugs me is that i'm running a relativley low IFR (at least based on what I belived my injectors to be) and my VE's are all screwed up from my previous attempts to get my car inline. And even though drivebility has improved I'm getting more bucking and a rougher idle than I did when I was having those huge lean surges. Basically I've got a mess on my hands and I want to start with a fresh slate so..

    I'll definatley keep you guys updated as I progress and try some new approaches based on my readings and hands on tinkering. More to come woohoo!!
    Dave
    -'07 Acura TL Type-S
    -'07 Honda Ridgeline RTS
    -'00 Pontiac Trans Am WS6

  9. #19
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    We installed 42# Delphi injectors in a 5.3l last weekend along with a Whipple and a cam.
    After my initial approach of using 6.1xxxxg/s I also got LTFTs at 25%. I then reduced IFR to 5.03 and got LTFTs from -5% to 10% with some areas very close to 0%.
    The VE table is raised quite a bit, too. Too bad we could not hook up the wideband as the connector did not fit .
    2005 RCSB 2500HD GMC Sierra DURAMAX LLY
    1955 Chevy Truck 1st series, being restored
    2002 Mercedes C270 CDI

  10. #20
    Lifetime Member hquick's Avatar
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    Just for the sake of it....here's my current tune and a log from this morning.
    I'm running OLSD and have the VE table pretty well dialled in. Cruising is absolutely spot on.
    Lately I've been toying with the lean tip-in and rich decel/lean...after decel (won't see that in this log as I re-enabled DFCO).
    You can see that my VE table looks like no other???
    Waiting for my RR to arrive so I can play with the injector settings (pulse widths..etc) a little easier.
    Attached Files Attached Files
    Howard

    YOU ONLY NEED TWO TOOLS IN LIFE - WD-40 AND DUCT TAPE. IF IT DOESN'T
    MOVE AND SHOULD, USE THE WD-40. IF IT SHOULDN'T MOVE AND DOES, USE THE
    DUCT TAPE.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.


    98 K1500 'HOLDEN' Suburban.
    Custom Whipple SC, Mercruiser Marine intake, 0411 PCM, 4L80E w/shift kit

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