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Over accelerating when driving

14K views 28 replies 8 participants last post by  Richy 
#1 ·
Hi all.Have a problem with my antara.Spanner light is on but no engine management lightwhen driving car it is accelerating on its own.Can drive without foot on acceleratetor pedal n having to use brakes to slow down to stop going over limit it also seams to be running rough but idling at 14000 revs n will stay at that.Only speeds up when driving.Any ideas would be appreciated thanks.2.2 diesel 12 reg
 
#2 ·
John h said:
Hi all.Have a problem with my antara.Spanner light is on but no engine management lightwhen driving car it is accelerating on its own.Can drive without foot on acceleratetor pedal n having to use brakes to slow down to stop going over limit it also seams to be running rough but idling at 14000 revs n will stay at that.Only speeds up when driving.Any ideas would be appreciated thanks.2.2 diesel 12 reg

Idling at fourteen thousand revs? Did somebody fit a jet engine in it? Sorry J, just couldn't resist it.


Sounds to me like the accelerator position sensor switch could be faulty because it's a drive by wire system but you really need to get your fault codes read to see.
 
#5 ·
hi cleaning the accelerator ? were is this any idea ? want to try a quick fix i need to take to get codes done but when i drive car its trying to go on its own 14000revs lol ya last time i saw my car do that many revs it was a insignia eat itss own oil ran for ten mins made more smoke than space shuttle taking off
 
#9 ·
can you get any live readings from the engine ecu , if yes have a look to see what percentage the throttle position is at , usually 0 its off 100 % its fully open and your around 5k rpm check throttle butterfly not sticking open . this will show if fault with throttle , check for air leaks .
 
#10 ·
I had a similar problem with a mk1 sorento. It was my fault. I drove the car into an automated car wash with the sunroof on tilt, i didn't know it, but on this car the engine ECU is located in the passenger footwell which flooded with water. The water got into the ECU and the revs started elevating. Fortunately I lived close and got home using the brake. It was a big job to dry out. So if the thread above shows the throttle is ok I think this may be an ECU problem. Granted the ECU on a Antara is in a different location.
 
#11 ·
Intermittent fault....service light on but no engine management light
Press break peddle the idle rev go back down but when driving it can drive 15 mph in 1st 20 in 2nd 3rd will do 25 4th 35 5th happily do 40mph all without touching the accelerator 🤔🤔🤔 tested the gear changes in local carpark....completely confusing
 
#12 ·
Yes
When you press the brake pedal it disables the accelerator in the ECU, I think that is standard on all cars. If you have ever tried it. You cannot normally accelerate and brake simultaneously. So if ok when you press the brake pedal, doesn't this point to an accelerator problem.
 
#14 ·
Just had a look on 7zap and it looks like this part, the accelerator pedal, may of been superseded. The original part number was 96625895 which is no longer stocked and replaced by 20905700. I'm surprised to see a few on Ebay so your problem may not be a one off. What I don't know is whether the accelerator has to be configured in the ECU or whether it can just be swapped out. Perhaps someone else on the forum may know.
 
#15 ·
Thanks well taking it in sat and I'll cross my fingers they know whats up . .one strange thing i found out yesterday tho....when my stop start kicks in at the lights (very rarely use it) the moment i touch the clutch the engine starts back up on normal tick over and stays ok for around 10 or so min 🤔🤔
 
#16 ·
ooooooooooooh
Now. that does seem strange. If that is the case it might blow the accelerator theory out of the water. Seems it could now be ECU related. its as though the ECU is losing its calibration. I totally guessing now but could this be a bad connection. Have you checked all the plugs onto the ECU and accelerator ? Have you had any ingress of water ?

At least you can get your stop start to work, since I changed my starter the only time when my stop start works is when I'm towing my caravan, when I really don't need it. Typical Antara. my car drives me insane sometimes, well most times, but I love towing with it. Its a perfect towcar.
 
#17 ·
Thanks richy for all your help. .will keep you informed after they take a look at it ...it's just now i feel a little better going in there as usual I walk in with a magical sign that reads 'rip me off as I done know anything" ps feel your horror ovee the stop/ start as mine just work the odd occasion.....think it has to do with aircon and other strange things the antara decided the stop starts is not needed lol
 
#19 ·
Hi there strange update on this.....probably was fixed by a simple reset of check engine light....(at the moment anyway) Vauxhall reasoning was 4 faults kicked in due to dpf not finishing it stuff probably....temp fault, air flow fault, and two other fault they forgot to mention.....says with the joint fault picked up the engine management kept the change gear smoothly thingy kick in permanently....full health check showed all ok so cross finger... all this worry for £95 fix 😊😊😊 if problem starts again I'll keep you informed
 
#20 ·
From bad to worse....light came on so took it back and now they say the it's a number 4 injector code and glowplug....want to charge me £960 to fitnew injector new egr valve and 3 glow plugs.... all this without first testing them!!! Just cos code told them!! Going to book it in for a test and also put so redex in just to see....my guess (maybe wrong but if car is over revving then the injector would notice more fuel trying to be used so would flag up a code and might not be the initial problem 🤔🤔🤔
 
#22 ·
Jimmas that's was my first worry as cleaning one of them on a antara os experience ....but with the stop start resetting the revs my thoughts turn off that idea as (my thinking this is and could be wrong) the stop/start eco mode is resetting the sensor so if it was the throttle body it would still be over revving...so i think🤔🤔 possibly a sensor is picking up more intake so it's compensating for it but with the higher fuel using the engine is getting dirtier so going to try redex and see if this clears and of the main expensive fault leaving hopefully a simple one fault pick up....my be wrong but worth a try before digging deeper into the bank account

Please forgive any spelling and grammatical mistakes as these we're spared to save time lol
 
#23 ·
Hi Proplus.

I share your grief mate, this is just a hole to throw money at. Did you try the Injector cleaner, years ago back in the old days of sierra 2.3 diesels I was once advised by a taxi driver to use forte diesel injector cleaner, they used to throw a can in the tank regularly which used to keep their cars running sweet. Having spoken to Forte they also claimed that in extreme circumstances you could use the fluid undiluted. So I tried this with no issues. You take the diesel filter off and empty out the diesel then refill with neat injector cleaner, refit the filter and bleed any air out, then just start the car. All unused cleaner ends up back in the tank anyway so it could be worth a try. On another approach if this is electrical you could try disconnecting all the electrical connections to the injectors etc, then look for any corroded terminals or damaged cables, if you have a code reader then try resetting the codes and see what happens. I would disconnect the battery and wait 30 mins before you disconnect any cables though. Just consider your situation is unusual so its just possible your fault may be also, don't necessarily jump to automatically replacing injectors as they are expensive. Richy
 
#24 ·
Trust me bank account say no to the injector at the moment so mild hots on it to test area out should be out just picked up a fault reader and injector cleaner so trying it now ...hopefully is the light comes back on I'll be able to read the first fault that happens and trail and error my way through this 🤔 thanks for all the in put and will keep you informed especially if the problem doesn't come back 🙂
Cheers and really mean that
 
#26 ·
Hi sorry haven't replied soon but just did want to jinx it
So....Vauxhall wanted to change the number 4 injector 3 glow plugs and two egr valves all totaling to £944

Plan of action was to start with injector additives (the simple solution first) then slowly work my way testing each parts everytime the light reappeared

So code read at hand ( cos they didn't even reset it this time) and fuel + additive, off we go


Welll 240 miles in and not a light or problem soo far on the minus side tho...did get a spending ticket (karma for inwardly laughing at the receptionist who told me I could pay in 4 installments but wouldn't get the 25% discount from being a Vauxhall member if i did....she then spent 10 minute working out how much the installments would be and the another 20 min working out how much I'd save if I paid in ine go with my 25% of.....she was very surprised to see I'd save the same amount as i would be paying each month. .. . Oh bless the youth of today 🤣🤣) anyway back on the topic... . So far the car purrs at 700 rev in idle and once in gear drives like a dream (including better mpg)
Might be just a fluke but my advice with anyone being told a high price to fix something research, think logical and get a second opinion before just believing the first diagnosis....
Thank you all for helping out and please forgive my spelling and grammatical errors yet again 😊😊
 
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