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ECMlink Stuttering/hesitation-ahhh!

Posted by Vegas smith, Dec 4, 2018

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  1. Vegas smith

    Vegas smith Proven Member

    2,191
    949
    Joined Dec 2, 2002
    Houston, Texas
    1). Any boost, vac, or exhaust leaks?
    No
    Boost leak tested 5psi above your max boost with no leaks?
    Yes

    2). Verified mechanical timing?
    Yes

    3). Verified base timing?
    Yes

    4). Ignition system
    COP or Stock Coil: Stock
    Wire brand and Age: NGK
    Spark Plug brand, type and Gap: NGK-BR7ES/.028



    5). Motor health (Compression Test)
    Cylinder 1: 160
    Cylinder 2: 160
    Cylinder 3: 160
    Cylinder 4: 160

    6). Performed basic throttle body adjustments?
    Idle Switch: Yes
    Throttle Cable: Yes
    TPS: Yes
    BISS: Yes

    7). Compression ratio
    8.5:1

    8). Any known bad sensors or brittle wiring?
    No

    9). Any DTC/CEL codes?
    No

    10). Electrical system
    Car off (not running): 12.4 volts
    Car running: 13.9 volts

    11). Base fuel pressure and injector values
    Base Fuel Pressure: 43.5
    Injector Size (cc/min): FIC hiz-1650

    12). Properly calibrated and configured wideband sensor
    Sensor Brand: LC2
    Calibration Date: 11/30/2018

    13). Type of fuel
    Type: 93 Octane
    Percent of Ethanol: 8%

    14). Watched ECMlink how-to videos?
    Yes

    Hello all, A couple months ago I completely rebuilt my car and ever since then I've had this severe stuttering/hesitation. As you can see from the logs the car sputters and you see a jagged TPS, wideband and MAP. I have no idea why this is. Kevin Jewer thinks it has something to do with the TPS but I can't find anything wrong with any of the wiring. I've tried all new sensors and jiggling of wires near tps and ecu with no difference. The TPS is not improperly grounded either. No idea what this could be. I've looked for shorts everywhere and have checked and re-checked mechanical timing and other sensors as well. Thanks
     

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    Attached Files:

    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  2. boostdawd

    boostdawd Supporting Member

    1,101
    295
    Joined Apr 6, 2010
    phoenix, Arizona
    Cant see your log due to no laptop but when does it hesitate? Wot?

    If hesitation is at wot try closing the gap on your plugs to 22. How much boost are u running?
     
    My DSM:
    1997 Eagle Talon TSi AWD

    Street Build

    16g   automatic
    1991 Eagle Talon TSi AWD

    Drag Race Build

    GT35   manual
    1992 Mitsubishi Eclipse GSX (sold)

    Street Build

    16g   manual
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  3. Vegas smith

    Vegas smith Proven Member

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    Houston, Texas
    It hesitates at all loads. I cant even go WOT on the car with this issue. I've tried different PTUs, CAS, TPS, Coil, plugs, wires, o2 sensor, wideband sensor (happen to have all this stuff laying around). Injectors have been cleaned. Fuel pressure is good. Ecu was in for repairs last year and I can't find any obvious damage on the board. New gasoline.
     
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  4. boostdawd

    boostdawd Supporting Member

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    phoenix, Arizona
    Did u rececently replace cams or did any timing work? My car had a stumble/lack of power after I swapped cams back to stock. Turns out one of the rockers was not seating right on cylinder 1 causing this.
     
    My DSM:
    1997 Eagle Talon TSi AWD

    Street Build

    16g   automatic
    1991 Eagle Talon TSi AWD

    Drag Race Build

    GT35   manual
    1992 Mitsubishi Eclipse GSX (sold)

    Street Build

    16g   manual
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  5. bastarddsm

    bastarddsm Supporting Vendor

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    Mendota, Illinois
    Try another ecu.
     
    My DSM:
    1991 Eagle Talon N/T

    Showcar Build

    9.805 @ 144.00 MPH
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  6. Bleakley

    Bleakley Supporting VIP

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    Joined Jan 29, 2017
    Pittsburgh, Pennsylvania
    What are you using specifically to show crank and / or cam signal to PCM?
    Rebuild, hesitation at all loads, circuits checking out. I’d question the validity of the timing of the electrical signal to the pcm.
    I haven’t gotten TOO in depth with these cars yet. But look and see if your electronic values for your timing are lining up with the actual timing.
    Example, if there’s a way to identify crank signal is sensing 10* BTDC #1 cylinder at rest —> verify that cylinder is where the sensor says it is. Same with cam.
    If I ever get to a computer I’d like to look at the log.
    Will be keeping tabs on this...

    Edit: Give an example, I’ve seen first hand on a Ford where the trigger wheel for crank sensor on harmonic balancer (which is pressed on btw) somehow f***ing moved, placing everything out of time electrically. Fricken wild... The Ford was so out of time it wouldn’t start, but if yours is only little out, maybe? It could cause that?
    What are fuel trims doing?
     
    My DSM:
    1995 Eagle Talon TSi

    Street Build

    16g   automatic
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  7. Vegas smith

    Vegas smith Proven Member

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    Houston, Texas
    New gsc s2 cams (gets yelled at by bastarddsm for too big a cam ), new CB 2g head, new fidanza cam gears. I'll check rockers again but I'm pretty sure they're good.

    Yes sir, will do.
    Fuel trims are OK. A little too inconsistent. I'll check on the timing verification.
     
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  8. bastarddsm

    bastarddsm Supporting Vendor

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    Mendota, Illinois
    Unplug tps and drive it. See if problem goes away.
     
    My DSM:
    1991 Eagle Talon N/T

    Showcar Build

    9.805 @ 144.00 MPH
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  9. Vegas smith

    Vegas smith Proven Member

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    Joined Dec 2, 2002
    Houston, Texas
    Good suggestion, will do that.
     
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  10. Bleakley

    Bleakley Supporting VIP

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    Pittsburgh, Pennsylvania
    Agreed.

    But Bastard, what will ecu use to determine load though?
     
    My DSM:
    1995 Eagle Talon TSi

    Street Build

    16g   automatic
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  11. bastarddsm

    bastarddsm Supporting Vendor

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    Mendota, Illinois
    The ecu normally never uses tps for load.
    It uses airflow/rpm
     
    My DSM:
    1991 Eagle Talon N/T

    Showcar Build

    9.805 @ 144.00 MPH
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  12. Vegas smith

    Vegas smith Proven Member

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    Joined Dec 2, 2002
    Houston, Texas
    TPS unplug did not help....now I gotta track down somebody in Houston who will let me borrow link.
     
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  13. bastarddsm

    bastarddsm Supporting Vendor

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    Mendota, Illinois
    Did you get a check engine light? Is your ecu a factory eeprom, or a converted one?
     
    My DSM:
    1991 Eagle Talon N/T

    Showcar Build

    9.805 @ 144.00 MPH
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  14. motomattx

    motomattx Proven Member

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    Joined Dec 9, 2010
    wampum, Pennsylvania
    Your likely backfiring through the intake which is bouncing your throttle plate, causing your tps signal to spike all over the place and your map signal to spike all over the place and your fueling issue is causing your wideband to also be all over the place. Sounds like you have a fueling issue, too much or too little or ignition timing is out, also are you sure that your cas is not installed 180 degrees out?
     
    My DSM:
    1995 Mitsubishi Eclipse GST

    Drag Race Build

    GT42   manual
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  15. Bleakley

    Bleakley Supporting VIP

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    Pittsburgh, Pennsylvania
    On MAF, I think he’s Speed Density.

    I need to get to a computer so I can view your logs. Lol. Suspense is killing me.
    I’ve seen on IDS on Fords w/ EGR the pulses will def foul sh*t up. Supporting what motomatt said.
    if that helps at all...
     
    My DSM:
    1995 Eagle Talon TSi

    Street Build

    16g   automatic
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  16. bastarddsm

    bastarddsm Supporting Vendor

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    Even on speed density it uses airflow/rpm to come up with load for the map indexes. It without doubt never uses TPS for load unless your in a crazy limp home mode.
     
    My DSM:
    1991 Eagle Talon N/T

    Showcar Build

    9.805 @ 144.00 MPH
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  17. Bleakley

    Bleakley Supporting VIP

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    Pittsburgh, Pennsylvania
    Gotchya. Def got more reading to do.
    Clearly misinterpreted some info I think. What I’ve deduced is while the throttle plate may dictate load (airflow), the throttle position signal does not. That sound about right?
    Thank you. :)
     
    Last edited: Dec 6, 2018 at 4:27 AM
    My DSM:
    1995 Eagle Talon TSi

    Street Build

    16g   automatic
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  18. Vegas smith

    Vegas smith Proven Member

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    Joined Dec 2, 2002
    Houston, Texas
    I didn't even bother driving the car because it was falling on it's face just revving it with my hand, therefore, I'm not sure if it pulled a code. I'm also uncertain about the ecu as I don't know a whole lot of about our ecus. Haha, I probably knew this answer 15 years ago, though. I can look into all this tonight after work. Thanks.

    I've always felt like this is the case. I think the tps/map/wideband are symptoms of some other problem. I'm pretty sure the cas isn't 180 out because you can really tell when it is. The car has a bigger lope with the S2s than the bc272s that they replaced but I wouldn't call it abnormal. I don't think the timing and ve tables are far out balance so I don't suspect a tuning issue either. I've even tried disconnecting my arc-2 and that doesn't help either.
     
    Last edited: Dec 6, 2018 at 8:04 AM
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  19. Bleakley

    Bleakley Supporting VIP

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    Pittsburgh, Pennsylvania
    Standardized durations of:
    BC0101 —> 208/212 @ 0.050”
    BC0104 —> 220/220 @ 0.050”
    GSC S2’s —> 230/230 @ 0.0394”

    So uhh, I’d have to look at the entire spec of the cams to determine LSA’s / overlap, but looking strictly at those durations —> if you tuned on BC0104 and jumped to GSC S2’s, that’s a pretty sizeable difference for airflow/VE (estimating maybe 226-228 @ 0.050” for the S2’s).
    If you jumped from the BC0101’s, good god!
     
    My DSM:
    1995 Eagle Talon TSi

    Street Build

    16g   automatic
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  20. Vegas smith

    Vegas smith Proven Member

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    Houston, Texas
    I'm not making the argument that the car will run great on an old tune but I also don't buy the car would be almost undriveable just because of the new parts. I'd expect the car to be choppy but not backfiring/stuttering so badly.
     
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  21. bastarddsm

    bastarddsm Supporting Vendor

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    It's tough to say on this. Everything affects everything, and weird sh** happens. I cannot imagine a backfiring issue modulating the throttle plate and showing up on the datalog - but anything is possible. Generally I'd believe that a cam swap shouldn't make it underiveable, it might run poorly, but it shouldn't be that hard to fix up the VE map. I don't think it's that much of a cam swap here.

    Does this car have a crank trigger? Are the plug wires on right? I've seen that happen, plug wire switched. It'll start and run sometimes, but not well.

    We are getting OT here, but throttle angle is not a good indicator of engine load on a turbo car, so it is never used. You can have wildly varying manifold pressure at a constant throttle angle.
     
    My DSM:
    1991 Eagle Talon N/T

    Showcar Build

    9.805 @ 144.00 MPH
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  22. Vegas smith

    Vegas smith Proven Member

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    Joined Dec 2, 2002
    Houston, Texas
    It does not have a crank trigger. I've tried new plugs, a COP setup and a new CAS. Nothing has helped at all. Wires are on right and that's further evidenced by the problem also occurring with the COP setup. Tried a different PTU as well.

    Also, I've tried different ve maps and have tried to tune the ve map myself as well as use the Sd Adjust tool. None of that has helped this problem at all.
     
    Last edited: Dec 6, 2018 at 1:34 PM
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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  23. Bleakley

    Bleakley Supporting VIP

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    Helps me learn though. Thanks Bstddsm.
    (Thanks Vegas for allowing a very small subsection of thread jacking)
     
    My DSM:
    1995 Eagle Talon TSi

    Street Build

    16g   automatic
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  24. jakk220

    jakk220 Proven Member

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    Akron, Ohio
    +1 on checking this. My last engine build my friend hooked up the spark plug wires as if it were his Evo. So he was counting cylinder 1 as cylinder 4. The CAS was also 180 out if I remember correctly. Either way the car started and sounded like a normal cam idle. The motor would rev up decently well but didn't sound right. When I tried to set the timing with a light and could not get it right that gave away that something was wrong.
     
    My DSM:
    1997 Eagle Talon N/T (sold)

    Autocross Build

      manual
    1993 Mitsubishi Eclipse GSX

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    16g   manual
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  25. Vegas smith

    Vegas smith Proven Member

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    Joined Dec 2, 2002
    Houston, Texas
    My timing light worked fine when I set the timing. It's unlikely that the wires are the cause as I threw on my COP setup. Also, I'll double check the CAS.
     
    My DSM:
    1993 Eagle Talon TSi AWD

    Street Build

    GT30   manual
    1992 Eagle Talon TSi AWD (sold)

    16g   manual
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