Hesitation under acceleration - GS

toole26

toole26

Junior Member
Messages
94
Hesitation under acceleration seems to have developed today, 1st, 2nd and 3rd when progressively applying the throttle - its almost like slight fuel starvation or something similar, potentially gearbox related.

Any ideas what this could be? its not the usual jerky changes around town at low speed, this is something different.
 
toole26

toole26

Junior Member
Messages
94
Problem fixed, apparently the throttle needed reset as the exhaust guy caught the brake and throttle at the same time when starting the car.
 
toole26

toole26

Junior Member
Messages
94
switched on ignition, (not starting the car) put car in neutral then left it with dash lights on for 30 secs, then put accelerator hard to the floor for 30 secs, I then started the car and went for a drive and it seem to have cleared it, its very smooth now through the full rev range.
 
conaero

conaero

Forum Owner
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34,632
Glad it’s fixed. If it keeps doing it consider changing the pedal pot, we do loads of them with similar issues
 
T

TimR

Member
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2,731
Having just swapped the pedal pot’ on my manual 42gt, it would makes sense if it was necessary to do the same thing with respect recalibrating the thing by resetting the throttle as above....
Anyone care to confirm it should be done...?
Cheers
 
philw696

philw696

Member
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25,483
TimR said:
Having just swapped the pedal pot’ on my manual 42gt, it would makes sense if it was necessary to do the same thing with respect recalibrating the thing by resetting the throttle as above....
Anyone care to confirm it should be done...?
Cheers
Click to expand...
If you disconnected the battery first you won't have upset the happy medium.
 
T

TimR

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2,731
philw696 said:
If you disconnected the battery first you won't have upset the happy medium.
Click to expand...
Mmm..I didnt. Because that resets the whole "throttle learning" set up !
Reading between the lines..the potentiometer doesnt need the ecu to see where shut & open is then..( Of course it does, but that replacing it with a another potemtiometer isnt likely to introduce enough variation to the ECU for it to go a bit weird...) Just plug it in, and go !
Hah..I see there's a pedal bump stop down there.. I was thinking I might just wind it in some. Gotta be good for a good +10BHP I reckon !
 
toole26

toole26

Junior Member
Messages
94
This issue has returned, I think I’ll need to replace the pedal pot by the looks of it.
 
T

TimR

Member
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2,731
Bummer...!
I’d recommend removing the front seat to make access easier. It’s pretty simple.
An ex tree climber sometime retired, access and work- positioning in the footwell d4mn near killed me tbh.
:p
 
toole26

toole26

Junior Member
Messages
94
TimR said:
Bummer...!
I’d recommend removing the front seat to make access easier. It’s pretty simple.
An ex tree climber sometime retired, access and work- positioning in the footwell d4mn near killed me tbh.
:p
Click to expand...

so this unit sits just above the pedal box does it and pretty straight forward to swap out?
 
T

TimR

Member
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2,731
toole26 said:
so this unit sits just above the pedal box does it and pretty straight forward to swap out?
Click to expand...
I can make the simplest jobs difficult but essentially; yes!
The access, with both hands free to manipulate the few screws it takes to get it free, is the “crypton -factor” element here really...
As Phil noted- might be best best to isolate the battery before disconnecting it. Reset it as per your above post I’d say. Having the right length Allen keys will also make a molehill of an otherwise awkward mountain... Also then do a throttle reset ( because the battery isolation resets the trim values in the ECU to default factory..) This helps the ECU relearn all those values within adaptive parameters
I’ll post the process below for you....
 
toole26

toole26

Junior Member
Messages
94
TimR said:
I can make the simplest jobs difficult but essentially; yes!
The access, with both hands free to manipulate the few screws it takes to get it free, is the “crypton -factor” element here really...
As Phil noted- might be best best to isolate the battery before disconnecting it. Reset it as per your above post I’d say. Having the right length Allen keys will also make a molehill of an otherwise awkward mountain... Also then do a throttle reset ( because the battery isolation resets the trim values in the ECU to default factory..) This helps the ECU relearn all those values within adaptive parameters
I’ll post the process below for you....
Click to expand...

ideal thanks Tim, very helpful
 
T

TimR

Member
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2,731
1, complete your work
2, drop the driver's window at least 20mm
3, switch off the battery isolator switch in the boot (either leave boot open or make sure your key works in it first!)
4, wait 30 minutes
5, switch on isolator switch, close boot and cycle the locks once (so the alarm doesn't go loopy)
6, start the engine without touching the throttle or any other controls, idle the engine for a full 10 minutes
7, turn off the engine having not touched anything else
8, restart the car and drive for a full 20 minutes in your own style (or like you stole it!)
Done!
 
toole26

toole26

Junior Member
Messages
94
TimR said:
1, complete your work
2, drop the driver's window at least 20mm
3, switch off the battery isolator switch in the boot (either leave boot open or make sure your key works in it first!)
4, wait 30 minutes
5, switch on isolator switch, close boot and cycle the locks once (so the alarm doesn't go loopy)
6, start the engine without touching the throttle or any other controls, idle the engine for a full 10 minutes
7, turn off the engine having not touched anything else
8, restart the car and drive for a full 20 minutes in your own style (or like you stole it!)
Done!
Click to expand...

ok, so;

  1. fit the new unit as you’ve described
  2. Do my throttle procedure I was referring too
  3. Do your ecu reset you’ve just described
 
conaero

conaero

Forum Owner
Messages
34,632
You can do the pedal pot with the seat in situ.

there is one hex head with a medium bar you access it through the brake pedal at the back.

Its fiddly rather than difficult.

Whilst you are working on the throttle, take the intake to throttle body off and give the butterfly and tube a good clean with brake and clutch cleaner…also know as carb cleaner

NEVER manually open the throttle body with your fingers and put them in there with the battery connected.

Your finger swearing gesture capabilities will be removed from you in an instant.
 
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