Z20LET Hanging Revs Sticky Throttle

[DaveB]

I've got a weird problem with my astra turbo. After a random period of time the car will develop a weird problem;

it's as though the throttle is 'delayed'.

i.e. If you change gear quickly the revs rise as though you've left your foot on the accelerator.

If you accelerate and then simply let off the accelerator the 'dump' is delayed (again as though my foot is still on the pedal)

If I turn off the car, and back on again then the fault immediately disappears, only to return later on. - again at this point a restart cures the problem.


Parts I've replaced:

AFM
Front BCS
Rear BCS
Map Sensor
Throttle Body
Accelerator Pedal
OE Dump Valve (for a forge recirc)


Anyone got any ideas?

[dearing5]

i have this problem on my c20let... strange! i got told it was down to the heavy flywheel but i doubt thats your prob..

[oz_speed]

i have the exact same problem with my z20let, but seems worse now i have removed the bailey dump valve!!

[Astra Dan]

There's a ground mod where you find a point where a bunch of ground wires are all commoned into one, next to the battery, inside the loom tray. You solder another wire on and take it straight to battery -ve. Not sure what problems this solves, but might be worth a shot!

[DaveB]

I've seen that mod Dan, and reckoned to unwrap the loom to look for said offending item, but no joy. That either means I have a 'late' loom, or the mod has already been done (or I'm not looking properly) lol

[Astra Dan]

Crap.

Have you tried plugging it into opcom, see if the sensors give reasonable readouts? For example, my bro's mk3 Astra always ran ok wih no fault codes but always struggled with emissions at MoT time. Plugged it into opcom and noticed the ECU always thought the engine temp was running at 0oC for some reasoin, regardless of fitting a new sensor.

Might help track a problem. Like the throttle pedal has 2 variable resistances in, one increases in Ohms with the pedal pushed, the other reduces, for safety reasons in case one stops working. This, or the wiring to it might be dicky.

[DaveB]

I did some data logging with OPCOM last night Dan.

I've graphed all my results; the pedals/tps are all the same (bar the variances from my foot) but the only things that change are the afm voltage, kg, fuel trim and injector cycle - which to me says that air is still being sucked in after I've shut the accelerator off?

I think the extra revs is the air that SHOULD be 'dumped', but isn't - so I'm thinking maybe a vacuum leak?

[heds]

dave your car did that since we put the engine in it, also my coupe started doing it after changing the harness, ill put money on it its the clutch switch on the top of the pedal, mine wasnt plugged in but yours is but may have knackered ?

[oz_speed]

mines just wen it gets warm though, when cold its perfect but as soon as it gets worm the it over revs on its own??

[zmayich]

Does anyone know what is the problem...i think i have the same... if you turn engine off and start it again it will temp solve it...but later same shit...
thanks in advance!

[zmayich]

anyone?????????????????????????

[Corsa_LET]

It's your abs pump, my car doesn't have abs but I have it plugged in for the speedo, my mate had the same problem on his so we unplugged the abs & it stopped doing it. When your abs kicks in it ups the revs to stop itself stalling, this is what it's doing. Bet you if you unplug your abs for 10 mins the problem will go away

[zmayich]

I was thinking of that ****in abs, and one friend told me to try...I'll try it tommorow!!! THANKSSSSS!!!

[zmayich]

I unpluged abs modul today and HOOOREEEYYYY, the problem is gone!!! so is the km/h gauge, and the abs and tc light on can i fix the problem with km/h gauge working and no lights on??? THANKSSSS!!!

[Corsa_LET]

I should get paid for this lol does your car have abs? I'm afraid the tc & speedo work off the abs, the speed sensor is on the n/s front hub but I haven't figured out how to have the speedo working without the lights being on. My car doesn't have ABS so iv just learned to live with it

[zmayich]

i have one "evil geniuos" for opel/vauxhall in the hood so when he figure this out I'll put it here!!!