Engine & Gearbox Hesitation/revs drop

Discussion in '7th Generation (2003-2008) [Acura TSX]' started by Dave, Saturday 9th May, 2015.

  1. Dave Expert Advisor ★ ★ ★ ★ ★

    Sometimes when I go to pull away from standstill as I let the clutch peddle up the revs seem to drop right off and if I don't literally almost slip the clutch and keep the revs high it will stall. This doesn't happen all the time it could possibly be worse when it's warmed up.

    Now this has always been the case it's not getting any worse and it's been like it for the last 50-60k miles.

    It's more of an annoyance than anything else also if the revs are below about 1400rpm and you hit the loud peddle there is a bit of a delay before anything happens.

    Has anyone got any ideas? I've no faults stored, no warning lights, type of diesel makes no difference and you all know it's over serviced with genuine parts
     
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  2. Zebster Expert Advisor ★ ★ ★ ★ ★

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    I'm thinking it might be the Accelerator Pedal Position Sensor (also called the Throttle Position Sensor). This can usually be confirmed by contrasting how the car accelerates in response to the throttle pedal (where some hesitation/lag may be felt) versus how the car accelerates under cruise control when 'resuming' a previously set target speed (e.g. accelerates smoothly).
     
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  3. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Has it got a MAF sensor? I can't remember but had the exact same problem on my wife's yaris and cleaning it sorted things.
     
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  4. Dave Expert Advisor ★ ★ ★ ★ ★

    I'll try the cruise resume thing and see if it does it then. @ArcticFire what did you use to clean the MAF?
     
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  5. Ichiban Founder Staff Team

    England CJ Leeds
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    Dave you are around on Wednesday come down I can hook up the HIM on it and see what its moaning about?
     
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  6. ArcticFire-Account Closed Banned Getting Started

    Scotland Graham Scotland
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    Electrical contact cleaner
     
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  7. Dave Expert Advisor ★ ★ ★ ★ ★

    Unfortunately I'm not mate would be nice to get it plugged in sometime just to know if there is anything wrong with it and see if the injectors need calibrating and whether it's due any updates of any form.

    Still runs spot on for the mileage she's been a good one!
     
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  8. NottsBiker Top Contributor ★ ★ ★ ★ ☆

    Ben Nottingham
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    Great offer of help there buddy! Wish I had someone near me who knew about the throttle system as my snatchy set-up is driving me nuts (no pun intended!)
     
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  9. Zebster Expert Advisor ★ ★ ★ ★ ★

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    If your car accelerates OK when on cruise control (as I described above in my previous post) but then you suffer jerkiness, etc when using the throttle pedal it is almost certainly an APP sensor/TPS problem... it's easy to get at and the solution can usually be found in a can of electrical switch cleaner - I use some cheap Screwfix 'No Nonsense' penetrating oil, which is also a decent electrical switch cleaner (and comes in a ridiculously large can!)... No Nonsense Penetrating Lubricating Oil 750ml | Lubricants | Screwfix.com
     
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  10. NottsBiker Top Contributor ★ ★ ★ ★ ☆

    Ben Nottingham
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    OK thanks. That does sound like the problem or at least one to be looked at.
     
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  11. NottsBiker Top Contributor ★ ★ ★ ★ ☆

    Ben Nottingham
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    I removed my entire throttle system yesterday to check it out / clean it where possible.

    The TPS I assume is located where the throttle cable terminates? I removed the entire assembly but the electrical part of the assembly was sealed and I could not see how to inject any cleaner into it. I also removed the throttle body and completely disasembled it but found no obvious faults. The throttle cable free play was very loose so I adjusted this with only a small amount of free play but again this did not make a massive improvement. I did notice that the the gears inside have a negative stop and can only guess that the ECU can close the butterfly valve beyond where it normally sits in the idle position.
     
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  12. Zebster Expert Advisor ★ ★ ★ ★ ★

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    So your reported problem definitely isn't present when on cruise control then?

    Yes, it's where the cable terminates... it converts the physical position of the throttle to an electrical signal for the ECM/ECU. I can't help you with advice on dismantling your particular TPS... never done one on a K24, but I'm surprised there isn't some way of dismantling it to access the actual electrical converter.
     
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  13. NottsBiker Top Contributor ★ ★ ★ ★ ☆

    Ben Nottingham
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    Yes its great on cruise control and accelerates fine using the + / - buttons.
     
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  14. Zebster Expert Advisor ★ ★ ★ ★ ★

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    The proper test is to see how well it resumes a set speed from a much lower speed, as there is then a large differential and a more significant throttle response is required.
     
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  15. NottsBiker Top Contributor ★ ★ ★ ★ ☆

    Ben Nottingham
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    What would you suggest as a lower and upper speed to provide a decent range?
     
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  16. Zebster Expert Advisor ★ ★ ★ ★ ★

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    I suggest you set the cruise to be as fast as conditions allow in a high gear (not necessarily top gear), then tap the brake pedal to disengage cruise (but leave the setting active) then slow down to as slow as that gear will comfortably tolerate and then hit 'resume'... you may need to to experiment with different gears and/or speeds, but it should soon become apparent if the car is accelerating in a smoother manner when on cruise, compared to how it performs when under the control of the throttle pedal. If it's OK on cruise, then the problem must almost certainly be the TPS (APP sensor)... and maybe you won't be able to fix it with a spray, sometimes a secondhand part is called for,
     
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  17. NottsBiker Top Contributor ★ ★ ★ ★ ☆

    Ben Nottingham
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    Many thanks - I'll give it a go the next time I go up the M1
     
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  18. Zebster Expert Advisor ★ ★ ★ ★ ★

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    I hope this experiment gives you a clear and definite answer!
     
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  19. NottsBiker Top Contributor ★ ★ ★ ★ ☆

    Ben Nottingham
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    Yes me too. The snatchy throttle combined with the creaky clutch pedal is ruining the driving experience for me at present.
     
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  20. GSD2013 Premium Member Club Supporter

    I had this too, replaced both sensors under warranty as car went limp, i began to see the tachometer needle jumping and the car behaved like it was searching for fuel at 30 to 40mph around town. Eentually, it went limp and AA diagnosed 'fly by wire' pedal and throttle sensors were faulty. Fault codes 2510 and 250e.
     
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