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Thread: Please Help! I'm going insane with 950 EFI idling issues!

  1. #1

    Default Please Help! I'm going insane with 950 EFI idling issues!

    Just wondering if there is anyone there who can possibly help me out with an idling problem!
    I’ve recently fitted a Holley 950 Pro MPI system on a 460 BBF. I’m running MSD dizzy, Crane HI6
    Ignition, Edelbrock Victor inlet, 502/245 with 50 duration, capped of with a Holley 950 version 3.7 MPI System. Fitted in a 78 F100. (Not using Spark Control)
    Have had my share of teething problems, but have worked my way through it pretty well.
    But I still have an idling issue.
    It idles @ 900 rpm pretty good, drives pretty good, (still, no doubt a bit of fine tuning still to do) yet as soon as you put it in gear it will drop to about 550 rpm and when the A/C is turned on it drops to about 450rpm and will eventually stall. (as if the IAC wont compensate) If you increase the idle to say 1000 to 1100rpms it sends the IAC straight up to 200. And one is your smashing it into gear as well as you still have the idle issue once in gear or A/C on, it just about dies.
    I just can’t seem to get the idle to stabilize when it gets that bit of load. I’ve read a lot of the blogs and looked at most forums on the net and so far haven’t come across this problem as yet.
    I have played around with the Fuel map for hours and hours to no avail,
    Has anyone had the same problem or got any ideas! It is sending me crazy!

    Regards, Chewy

  2. #2
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    Try the suggestions in this post I wrote:
    http://www.chevytalk.org/fusionbb/sh...hp?tid/253395/

    Try these 'IAC PID terms': Proportional - 22, Integral - 18, Derivative - 32.
    How much timing advance are you using at idle?
    What air/fuel ratio are you using at idle?
    What size camshaft? (There's a misprint in your post about it.)
    Which wideband O2 sensor are you using?
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  3. #3

    Default

    Thanks for the quick reply Danny!

    Sorry I did make a stuff up with the cam size.
    (I had my wife type it up for me and can't quite work out where she got her figures from.)
    Anyway true size is 214/224 stage 3 its from Engine-Pro.

    My timing advance is about 8 degrees.
    The IAC PID are the same as yours above (I had already seen this on one of your previous posts.)
    I,m using a narrowband O2 sensor. (It's what came with it from Ebay and I new no different at the time.)
    O2 readings are low 8's at idle.

    I'm running 42lb injectors with 43psi

    Apart from idle it really runs pretty good.
    Cheers, Chewy

  4. #4
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    Quote Originally Posted by chewy View Post
    My timing advance is about 8 degrees.
    8° isn't enough for a smooth idle. I highly suggest at least 15° of idle timing.
    Also, your ECU should be controlling the timing with a TFI distributor.
    Then you could utilize Idle Spark Control and easily tune the ignition timing.
    I've got a great timing map for a 460 BBF engine. (It's a TBI file but it's a great base map.)

    I'm using a narrowband O2 sensor.
    You're really wasting your time; you need a wideband O2 sensor in order to tune an engine.
    I highly suggest Holley's own 534-197 WBO2 sensor kit; it's "plug & play" with the C950 harness:
    http://www.race-mart.com/Holley_Perf...L-534-197.html

    O2 readings are low 8's at idle.
    I assume this is the Lambda reading because you have a narrowband O2 sensor.
    0.80 Lambda is 11.76 air/fuel ratio, so you're definitely too rich.

    Since you & I have MPFI big block Fords, you'll probably enjoy my EFI conversion thread:
    http://www.network54.com/Forum/85220...old+Conversion
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  5. #5

    Default

    Hi Danny,
    Thanks for the info on Race-Mart, I have ordered the wideband kit. Will probably take a couple of weeks until I get it. So I will be able to give you some peace for a while.

    I was under the understanding that i couldn't use the spark control with using a CD ignition system? Could you explain more?

    I am very interested in your base map, how can I get it?

    I haven't done anything else yet as I will wait for the WBO2 to arrive.

    Cheers Chewy

  6. #6
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    Quote Originally Posted by chewy View Post
    I was under the understanding that i couldn't use the spark control with using a CD ignition system? Could you explain more?
    Are you kidding? Most of us use computer-controlled timing with a CD box.
    Look at the Wiring Diagrams in Appendix 10 of the C950 manual.
    Figure 75 - C950, TFI distributor with a CD box. (A BBF can be setup this way.)


    I am very interested in your base map, how can i get it?
    Click on my username and "Download vCard" for my email address.

    FYI: An Edelbrock Victor intake manifold with a 214°/224°@.050" camshaft is a
    major mismatch of engine components and not good for low to mid RPM torque.
    Last edited by Danny Cabral; 04-12-2012 at 03:19 AM. Reason: additional info
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  7. #7

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    Hello Danny,
    I sent you an email about 2 weeks ago now and haven’t heard anything, so thought I might drop you another line.

    Just to refresh you it’s a 1978 F100, I fitted a 460 BBF, cam 214/224 lobe separation 112, MSD 8540 Dizzy, Commander 950 Pro injection system, and it is now ECU timing controlled.
    About June last year you sent me a BBF-85-950 base map, and you recommended that I do an upgrade with a wideband oxygen sensor. That was the last time we communicated.
    It took until November to receive the unit, as the first one they sent got lost in transit etc.
    The BBF-85 base map didn’t come through properly; it couldn’t read the fuel map for some reason.
    I ended up pushing it back in the corner of the shed until now.

    Anyway, I have got it all together now and have a more confusing issue now.
    Am using the 347 base map from the Holley manual.
    Starts and idles reasonable at this point, (haven’t gone into fine tuning) but now I have another problem.
    At attempting to synchronizing the timing. And trying to follow your timing info I have taken from your other articles.
    Set my idle and locked the dizzy down. Can’t rev above 1750 rpm as starts to backfire severely.
    Sacrificed a dizzy cap and drilled an inch hole in top. Checked phasing with timing light.
    Found that it was trying to fire between 1 and 8. Bought an adjustable rotor from MSD, and got that right.

    But in doing this I found out what was happening when the backfiring is going on.
    When you rev it up everything is good until it gets to 1750 rpm, at this point it starts to backfire
    and while holding the timing light on the dizzy at number 1, the rotor starts to go crazy jumping from number 1 to 5 back to 1.
    Basically all over the place. I’ve replaced: - Dizzy cap and rotor, plug leads (Taylor Spiro-Pro), spark plugs,
    re-routed all wiring and plug leads, checked at night in dark for arcing. Tried playing around with spark map to no avail.

    You mentioned in your last reply that 214/224 and an Edelbrock Victor was a bad mismatch!
    What would you suggest? It’s not that bigger job to change it!
    I would appreciate your knowledgeable input into this please.
    I know it is something stupid and simple, but can’t put my finger on it.
    It’s getting close to being thrown back of the shed again.
    Kind Regards Always, Chewy

  8. #8
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    Quote Originally Posted by chewy View Post
    Hello Danny, I sent you an email about 2 weeks ago now and haven’t heard anything, so thought I might drop you another line.
    Sorry, I answer all emails, but I don't recall a recent one from you.

    MSD 8540 Dizzy, Commander 950 Pro injection system, and it is now ECU timing controlled.
    That's the wrong MSD Ignition part number?

    When you rev it up everything is good until it gets to 1750 rpm, at this point it starts to backfire
    and while holding the timing light on the dizzy at number 1, the rotor starts to go crazy jumping from number 1 to 5 back to 1.
    Seems like you know the problem...now to find the cause. Firing order correct? Wiring correct? Misfiring? TFI module? PIP sensor?
    http://www.holley.com/data/TechServi...l/R10149-7.pdf (Commander 950 EFI Manual - Ford TFI wiring, pages 100 & 101)

    You mentioned in your last reply that 214/224 and an Edelbrock Victor was a bad mismatch!
    What would you suggest? It’s not that bigger job to change it!
    An Edelbrock Performer dual-plane intake manifold is a much better match for your camshaft.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

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