Page 1 of 2 12 LastLast
Results 1 to 15 of 23

Thread: Voltage Drop on Acceleration Issue

  1. #1

    Voltage Drop on Acceleration Issue

    Hey guys:

    I have a 2003 trilogized Marauder with an unusual issue & would like your opinions. Under heavy acceleration my voltage gage drops from 14.5 down to 12.5 & stays there for a few minutes. Then returns back to normal. The issue is intermittent & does not always happen. It also affects the performance of the car. Any suggestions on what to look for.

    Thanks

  2. #2
    Join Date
    Nov 2003
    Location
    Horntown, VA
    Age
    65
    Posts
    4,810
    Quote Originally Posted by bones View Post
    Hey guys:

    I have a 2003 trilogized Marauder with an unusual issue & would like your opinions. Under heavy acceleration my voltage gage drops from 14.5 down to 12.5 & stays there for a few minutes. Then returns back to normal. The issue is intermittent & does not always happen. It also affects the performance of the car. Any suggestions on what to look for.

    Thanks
    This is normal - alternator is shut of at WOT by the factory program. They all do it.
    SOLD '03 300A Black - "805" of 7838
    Plate - "EVILMERC"

    I won't be wronged. I won't be insulted. I won't be laid a-hand on. I don't do these things to other people, and I require the same from them.

    Gillom Rogers: [Books is giving Gillom a shooting lesson] Mr. Books, How is it you've killed so many men? My spread wasn't much bigger than yours.
    John Bernard Books: First of all,friend, there's no one up there shooting back at you. Second, I found most men aren't willing, they bat an eye, or draw a breath before they shoot. I won't.

  3. #3
    It shouldn't affect the performance of the car, It's a 12v system so 12.5v is enough to run everything fine such as an upgraded fuel pump and high flow injectors. What exactly happens?
    FRPP dealer owner of SpartaPerformance.com
    We are an authorized independent AMSOIL dealer.

  4. #4
    Join Date
    Mar 2007
    Location
    Lehigh Valley, PA
    Posts
    5,956
    Quote Originally Posted by 2007VistaBlueGT View Post
    What exactly happens?

    When you go WOT, the computer disengages the alternator clutch so theirs less drag on the belt setup, freeing up a few HP



    thats whats happening


    2016 Ford Mustang GT PP - Lund nGauge, BMR vertical links, MGW Shifter, BMR CB005

    2004 Mercury Marauder - Eaton M112, Billetflow 3.4, Accufab SBTB + Plenum, T-56 Magnum, 4.10s, Stainless Works LTs, 2.5" Exhaust, Borla Stingers, Ridetech Coilovers + Adj rear shocks, FX-R projectors, Wilwood 13" BNSL6 + FNSL4 BBKs, S55 Gauge Cluster
    440rwhp & 406rwtq Tuned by Adam @ Revolution Automotive
    2063/3214

    (Sold) 2003 Mercury Marauder - Stainless Works LT's, Stainless Works 2.5" Catback, JLT Intake, Mo's Xcal4 Tune
    5377/7838

    2000 BMW M5 - Evolve Intake, Evolve Alpha-N tune, Stoptech ST-40 BBK, UUC SSK, Dinan front STB, Dinan RSB

    1996 Ford Bronco - 4" lift, 35" BFG A/T's, Punisher Valve Body, MH1 Projectors

  5. #5
    Join Date
    Jun 2003
    Location
    McDonough, GA
    Posts
    2,394

    Not Right!

    Your voltage should not drop that much. I would first check your soldered joint where the original alternator wiring was extended for the alternator's new position on the PS. If the extension was crimped - remove the crimp and insure it is well soldered with a good flame.

    Also, I would put another voltage gauge on the engine to measure the voltage. 14.5 is a little high. Note that the engine will not run up much past 4,500 without missing in park. It is a factory PCM command to do that.

    Glenn
    Trilogy #124 SOLD - 8/2014
    11.80 @ 117.16 MPH: SSHS9
    1.74 sec - 60'
    443 RWHP/437 RWTQ
    "Stock Internal Engine" - Click Below

  6. #6
    Join Date
    Jan 2003
    Location
    Hiram, Georgia
    Age
    61
    Posts
    17,780
    Low voltage on a fuel injected motor can lead to a blown motor, especially on a boosted motor.

  7. #7
    Join Date
    Jun 2005
    Location
    East Lansing, MI
    Age
    40
    Posts
    3,528
    Quote Originally Posted by offroadkarter View Post
    When you go WOT, the computer disengages the alternator clutch so theirs less drag on the belt setup, freeing up a few HP



    thats whats happening
    The clutch on the Alt. is not for acceleration, it is for decel. The EEC controls whether or not the Alt. charges...


    11.90 @ 117.5mph on 93 octane
    324 shortblock, Novi 2000, Now with optional axle removing tires
    Igziabeher

  8. #8
    Join Date
    Jan 2003
    Location
    Hiram, Georgia
    Age
    61
    Posts
    17,780
    The more I reread the OP, the more I am concerned for you.

    This is not "normal" especially if it is lasting for a few minutes and noticeably affecting the performance of the car.

    Het the alternator tested ASAP or you are in danger of losing a motor. Low voltage = a dangerously lean condition!

  9. #9
    Join Date
    Jul 2009
    Location
    NH
    Age
    55
    Posts
    7,606
    Worth checking your alternator and battery. You can pull the gauge pod and get a reading with a multimeter. Since you said the engine runs crappy though, im sure the reading is right.
    11.931 @ 116.33 (MT ET Streets)
    12.073 @ 118.43 (Nitto 555)

    I love the smell of Nitromethane and rubber in the morning!
    Drag racers prayer:
    As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

  10. #10
    Join Date
    Aug 2007
    Location
    Tulsa, OK
    Age
    50
    Posts
    102
    An alternator on a Trilogized motor doesn't have a clutch. It has a regular pulley, because the alternator is mounted backwards.

    Brian

  11. #11
    Join Date
    Feb 2003
    Location
    Purgatory, FL
    Age
    53
    Posts
    10,164
    I would check with Lidio at Alternative about this.
    (#6178 in black per FPIC)
    Call 1-800-FORD-788 and press "1". Have the last 6 of your VIN handy. You will get the numbers for FREE. You'll pay $$$ for the certificate.

    MM traded in 8/9/13 @ 128909 miles. It was fun for almost 8 years. I met airmercpun on 1/17/14. He was the new owner of my former ride. -Now gone.

    Update: back in the game with a late build 03 GMGS with some MM add ons like Escape audiophile radio w/Sirius sat radio, rear sway bar, catback exhaust, and header panel.

    Rest In Peace:
    Alex "Marauderboi" Vachon 3/2/92-8/13/10
    Paula Babineau 1/9/67-8/2/11
    Rex Weinbender
    Peter


    See my garage file for part numbers and whatnot.

    IMHO, this site- the members that I chat with- and the ones that I now Hang with- are like my 2nd family. There is such an ongoing welcome feeling here that even members who don't or no longer own the MM can feel.

  12. #12
    Join Date
    Jan 2003
    Location
    Near Knoxville TN
    Age
    67
    Posts
    10,717
    Sounds tune related. Maybe the alternator is still being shut off at WOT like the factory tune.
    Thanks to Darrin @ BC Automotive:
    $1800 and it was worse than when he started!

    Brian (FordNut) FPG # 1458 of 7838
    03 MM 300A (Lotsa mods, 130k mi) was 303rwhp/318rwtq N/A
    then 476/410 D1SC ProCharged on stock block
    then 660/555 D1SC PC on 5.3 wet sleeved Teksid alum big bore stroker
    then 365/369 N/A on 5.3 wet sleeved Teksid alum big bore stroker
    Now 751/617 3.4L Whipple on 5.3 Boss5.0 iron big bore stroker

    03 MM 300B Silver (Mostly stock, originally wife's car, 370k mi) FPG # 7053 of 7838 or 49 of 417 SB
    03 MM 300B Silver, Stock, wife's next one, 136k mi FPG # 7134 of 7838 or 89 of 417 SB
    04 MM Silver, Stock, on standby 85k mi, FPG # 1212 of 3214 or 432 of 997 SB
    01 F150 longbed
    01 F150 shortbed
    00 F150 4x4 stepside
    01 F150 4x4 7700
    68 Stang FB (70 351C 4V, 4 wheel discs, project car)

    Mods listed here (some items not current): FordNut's Mods

  13. #13
    Join Date
    Mar 2004
    Location
    Baltimore, Md.
    Age
    64
    Posts
    11,665
    Quote Originally Posted by offroadkarter View Post
    When you go WOT, the computer disengages the alternator clutch so theirs less drag on the belt setup, freeing up a few HP
    thats whats happening
    NO

    Quote Originally Posted by RR|Suki View Post
    The clutch on the Alt. is not for acceleration, it is for decel. The EEC controls whether or not the Alt. charges...
    YES

    Quote Originally Posted by Filby'sMarauder View Post
    An alternator on a Trilogized motor doesn't have a clutch. It has a regular pulley, because the alternator is mounted backwards.

    Brian
    YES

    Alternator clutch is to allow the alternator to momentarily 'freewheel' at higher rpms during an upshift when the engine suddenly slows from 6,000 rpm to @ 4500 rpm. It eliminates the belt chirp when the belt suddenly slows down the heavy alternator.
    It's like a bike's rear hub...you can drive it forward, but it freewheels when you backpedal.
    (That's why the reverse mounted Trilogy set-up requires a non-clutched alternator pulley)
    Engine computer can shut off the alternator's charging function at WOT to save on parasitic losses, if programmed to do so.
    Lot's of tuner's leave the alternator charging function on at WOT to avoid any potential drop in fuel pump function/fuel delivery.
    Most high HP cars even add a Boost-a-Pump to keep full voltage/slight overvoltage on the fuel pump(s).

    Your situation, because of the extended duration of the symptom, does NOT sound normal.
    Last edited by Joe Walsh; 10-22-2009 at 10:05 AM.
    2020 Ford Ranger STX DFI Turbo 2.3L 10 speed Auto
    2017 Ford Fusion Sport DFI Twin Turbo 2.7L V6 6 speed Auto (14.000 ET bone stock in 82 degree heat)
    1985 Mustang GT 5.0 Hatchback 4bbl 5 speed manual (525 HP 363 Dart block/AFR heads with Magnum 6 speed in the works)
    1984 Mustang GT 2.3 Turbo Convertible FI. 5 speed manual
    1966 427 Cobra (ERA) 468 all Aluminum FE 2x4bbl 5 speed manual

    SOLD : 2003 Mercury Marauder FI. 4 speed Auto
    w/Crower Cams & Springs, +1mm SS valves, mild port job on the cylinder heads.
    Extrude honed intake w/PHP spacer.
    Kooks Headers w/2.5" High Flow Cats & X-Pipe, Magnaflow mufflers, OEM tailpipes w/Megs Tips
    B&M Trans cooler w/fan, Level 10 Shift Kit, Art Carr Hughes Deep Sump Trans Pan,
    SVO Rearend Girdle, Redline Gear lube; OEM 3.55s
    'Real Gauges' + matching Trans Temp, Oil Temp, Water Temp, Fuel Pressure, Vacuum/Boost Gauge
    Built: 10/15/02 Bought: 12/16/02 Sold: 10/15/18

  14. #14
    Join Date
    Oct 2004
    Location
    Kentucky
    Posts
    3,000
    Sounds like what happened when my OEM alternator went out.

    As others have stated, I'd test it.


    1. Black Sunshine (2003A F.I.T #3) (SOLD!)
    2. 2004 SAP P71 (Gone)
    3. The 2001 P71 (Flying Snow). (Sold)
    4. The 1998 P71 Jinbei. (Sold)
    5. 1990 5.7L IROC-Z (Sold)

    Keeping a black car clean is not a hobby. It's a part-time job.

    Support the troops.

  15. #15
    Join Date
    Dec 2003
    Location
    New Port Richey,Florida
    Age
    56
    Posts
    827
    Quote Originally Posted by Glenn View Post
    Your voltage should not drop that much. I would first check your soldered joint where the original alternator wiring was extended for the alternator's new position on the PS. If the extension was crimped - remove the crimp and insure it is well soldered with a good flame.

    Also, I would put another voltage gauge on the engine to measure the voltage. 14.5 is a little high. Note that the engine will not run up much past 4,500 without missing in park. It is a factory PCM command to do that.

    Glenn
    Do what Glenn recommends chech the wire were it is soldered. If that is not the problem it could be the voltage regulator failing at high RPM this happened to me in my Marauder. Does your battery light come on at all?
    also use a multi meter under the hood at the battery while car is running.
    Sunshine State Marauders
    David
    Trilogy Supercharger#145
    2003 Black Marauder Now Grabber Blue
    300A Born 08-28-02 #4360

    [B]2003 Black Marauder
    300A Born 10-18-02 #5613
    Totaled 08-13-10
    Marauderboi (Alex)(RIP)My Son 03-02-92 to 08-13-10
    [B/]
    [IMG][/IMG]

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Voltage issue...
    By whtknt2 in forum Shop Talk
    Replies: 29
    Last Post: 09-14-2009, 06:25 PM
  2. supercharger acceleration
    By mercurymarauder in forum Community Discussion
    Replies: 72
    Last Post: 05-09-2007, 09:50 AM
  3. Headlight voltage drop
    By valleyman in forum Shop Talk
    Replies: 5
    Last Post: 10-26-2005, 10:08 AM
  4. Unintended Acceleration
    By JTBusfield in forum Shop Talk
    Replies: 16
    Last Post: 02-16-2003, 07:46 AM
  5. Voltage Drop
    By Zack in forum Community Discussion
    Replies: 5
    Last Post: 12-22-2002, 07:16 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •