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  • mssVT98
    replied
    Solution!

    Well, in my case it ended up being the AFM. Replaced it with new (alternatives just aren't feasible at the moment), and the problems appear to be gone. Plus the car is much smoother throughout the RPM range.

    So it wasn't the cheapest of parts to replace, but at least it's an easy install. And the shiny new metal looks nice.

    Hope this is helpful... seems to be a pretty common problem right about now.


    Mark

    Leave a comment:


  • arvzs1
    replied
    it was the oxygen sensor that's been causing the occasional power lose ive been experiencing for the past few days.what i did was disconnect the O2 sensor harness and the symtoms never comeback..
    the previous owner(1st) never change it sinced he bought the car brandnew and the car has hundreds of thousand mileage on it..imagine if the car runs on timing belt.
    checkout this thread, maybe it could help..
    http://www.s14.net/forums/showthread...5&pagenumber=1

    Leave a comment:


  • mssVT98
    replied
    In my case I don't think it's the TPS. At one point when I was having the problem, I disconnected it and still got the same symptoms. That was my first thought, but don't think it's the issue here.

    If it's the AFM, wouldn't the problem go away as soon as you changed throttle position? Then you wouldn't be in the dead spot anymore. When this started, I could depress the gas pedal several times and get no response. Then all of a sudden it would be fine. Now it's "progressed" to where if I give it gas it stalls. At idle I'm fine.

    The other thing I did before I was stranded was clean and reconnect the connector at the ECU. At first I thought that fixed it, but evidently not.

    Leave a comment:


  • arvzs1
    replied
    hey! can you pls. pm or email me

    when you get your car fix? im having the same exact problem too.
    my car will run normal at start and when on the highway, i'll press the gas at times and end up no power at all. i'll press and play the gas pedal or downshift to lower gear to recover the power. then it will kickback again to normal like nothing happen..
    to the next traffic lite, at full stop, the engine stall.
    kind of weird, the car run and operates normal and no signs of abnormal until awhile of driving..
    ty
    arvzs1

    Leave a comment:


  • mazenz
    replied
    Originally posted by wookie1976
    Also a bad AFM may cause similar problems especially if the mechanical "pot" is worn out. I believe that AFM's of our types tend to wear out most in common engine loading positions. This can lead to a dead spot, sending the ECU an incorrect signal.

    Try to see if another board member will let you try their AFM first. Its an easy swap and could lead to an easy (but not cheap) fix.
    the problem happens so intermittently that it could be weeks before it happens again for all i know. i dont think i could borrow somones afm for that long

    there are alot of suggestions here that i never would have thought about. when i get the time im going to try them all and ill post how it turns out.

    i also thought it might be a defective afm. if i had any money, id say its a perfect time to get rid of it

    Leave a comment:


  • wookie1976
    replied
    Originally posted by ColinM
    mssVT98 -- could be a malfunctoning idle control system.

    The idle system is triggered into action/inaction by the Throttle Position Switch (TPS).

    Diagnose the TPS and work from there.
    Also a bad AFM may cause similar problems especially if the mechanical "pot" is worn out. I believe that AFM's of our types tend to wear out most in common engine loading positions. This can lead to a dead spot, sending the ECU an incorrect signal.

    Try to see if another board member will let you try their AFM first. Its an easy swap and could lead to an easy (but not cheap) fix.

    Leave a comment:


  • ColinM
    replied
    mssVT98 -- could be a malfunctoning idle control system.

    The idle system is triggered into action/inaction by the Throttle Position Switch (TPS).

    Diagnose the TPS and work from there.

    Leave a comment:


  • mssVT98
    replied
    Been having the same problem

    I've been going through the exact same thing with my car. Until last night it was limited to zero throttle response, but only intermittently. Then I started having it stall every time I gave it any throttle. For better or worse, I was a lot closer to a local mechanic than to my house when it became undrivable, so I dragged it there. I'll post any solution that they come up with. Hopefully it's soon and not terribly $$$.

    Mark

    Leave a comment:


  • OnrailsM3
    replied
    At the back of the top of the motor behind and under the fuel rail is an aluminium elbow with a vapor return hose running into the intake. The elbow came loose and leaned the car out on me in the past. It caused symptoms similar to what you felt.

    It is under the hose that goes to the valve cover. Make sure it's tight cause it can lean out your motor and as our favorite house decorating convict would say "That's not a good thing"

    Leave a comment:


  • mazenz
    replied
    thanks for all the suggestions. its a crappy problem with many possibilities. again, thanks for the help.

    Leave a comment:


  • EVOIIIM3
    replied
    1. Change the fuel pump relay. it may shut off and cause this.
    2. check the 2 flywheel sensors, it's in the Bentley manual.
    3. Pull the plugs and make sure they all look the same. (sticking/leaking injector)
    4.Remove, clean & reinstall all the engine ground straps.

    Leave a comment:


  • mazenz
    replied
    Originally posted by Mmark
    The shutting off/cutting out/stalling at speed.
    Look for:
    1, broken ground wire near the ECU possibly.
    Are you getting alternator and spark noise thru the stereo?
    2, broken solder connections in the ECU.
    specifically , you open the case, remove the PCB and you'll see a big transistor with 3 connections to the PCB that is on a heatsink. this transistor is the ignition driver. sometimes the solder cracks at the connections, ie the thin circle around each connection. You may need a magnifier to see the break(s).
    3, The OBC box... driver side, green, 5"x8" can interrupt power from the main relay causing power loss and or no-start.
    If you use the OBC(code), it may need replacement. Otherwise you could pull the OBC plug and securely short the terminals in the plug together.

    RPM drop.
    Clogged fuel filter?
    fuel pump(s) problem?
    Bad wire causing a drop of one cylinder?

    Rear End

    This is in the suspension or the tranny mounts maybe.

    m
    1) no alternator noise
    2) and 3) never thought about that.
    rmp drop) i thought it might be the pump as well. it seemed strange that the problem was so intermittent, unrepeatable, and when the car was working normally, which is most of the time, it felt just as good as ever. ill have to check that out along with the filter. anyone suggest a possible fuel pump upgrade while im thinking of replacing it?

    is it possible to inspect the suspension mounts without disassembling the suspension?

    Leave a comment:


  • ADA///M
    replied
    TPS for 1 and 2

    Also check the motor and tranny mounts along with the guibo.

    Might as well check the diff bushing too.

    Leave a comment:


  • Mmark
    replied
    The shutting off/cutting out/stalling at speed.
    Look for:
    1, broken ground wire near the ECU possibly.
    Are you getting alternator and spark noise thru the stereo?
    2, broken solder connections in the ECU.
    specifically , you open the case, remove the PCB and you'll see a big transistor with 3 connections to the PCB that is on a heatsink. this transistor is the ignition driver. sometimes the solder cracks at the connections, ie the thin circle around each connection. You may need a magnifier to see the break(s).
    3, The OBC box... driver side, green, 5"x8" can interrupt power from the main relay causing power loss and or no-start.
    If you use the OBC(code), it may need replacement. Otherwise you could pull the OBC plug and securely short the terminals in the plug together.

    RPM drop.
    Clogged fuel filter?
    fuel pump(s) problem?
    Bad wire causing a drop of one cylinder?

    Rear End

    This is in the suspension or the tranny mounts maybe.

    m

    Leave a comment:


  • wookie1976
    replied
    I dont think the TP switch is the problem since it only really does anything at idle and WOT. You have problems all over the board. Id be more inclined to say fuel pump or clogged filter or line. You could have a corroded ground or power wire there as well.

    Leave a comment:

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