Hi,

 

When I'm driving around town at low revs (1.5k) at a constant speed, then come off the accelerator, the engine judders and there's kind of a knocking sound from the engine. The only thing I can think of (with my limited knowledge) that's wrong is the throttle cable is slightly loose as the effect is as though the throttle's bouncing? I have a feeling that this isn't the problem though and that's it's something else :confused:

 

Anyone have any ideas? Also, when idling, there's a bit of a popping noise from the exhaust as though the car's misfiring? So i'm not sure it's misfiring when I come off the gas or something.

 

Cheers,

Brian

over fueling?

It was overfueling quite a lot, but I just replaced the o2 sensors on thursday last week. There's now no black smoke from the exhaust under full throttle or petrol smell from the exhaust but I haven't run an ecu diagnostic yet to check if everythings working ok.

I think you need conzult.

Aye, it'd probably help! I'm also thinking it could be the fuel as i'm running 14+psi at the moment usin 95RON Asda fuel. I may go back to using Tesco99 like I used to in my 530i.

Aye, it'd probably help! I'm also thinking it could be the fuel as i'm running 14+psi at the moment usin 95RON Asda fuel. I may go back to using Tesco99 like I used to in my 530i.

 

Your using 95 ron on a chipped car... you have to be f''cking kidding me... ONLY USE SUPER WITH A CHIPPED CAR

The car was chipped t ZedWorld by the previous owner, he never said which petrol I should use so I just went by the petrol flap :(

I only use V power 99 ron. 95 is to low. 97 will be ok. This is why your car may be over fueling, you might get det so fill up on V power and give her a run.

tbh i cant see why different ron fuel would cause the overfueling, it would just det on higher boost.

 

could be a temp sensor fault? you need to get it on conzult to see whats going on and change to higher ron fuel straight away!! if you havnt damaged a piston yet you will do at some point ;)

i've just filled up the other day, should I grab a bottle of octane booster asap and stick it in the tank?

 

Cheers for the responses guys, I'll have to see if someone near me with conzult is willing to help me out.

i've just filled up the other day, should I grab a bottle of octane booster asap and stick it in the tank?

 

Cheers for the responses guys, I'll have to see if someone near me with conzult is willing to help me out.

 

you will be ok to use it just done go over 7 or 8 psi

 

also when you say juddering, do you mean the whole car juddering or the engine is cutting out?

the whole car is juddering, the engine doesn't stall or get near stalling.

Juddering when coming off the gas?

Gas !!!! I get the shakes after a few drinks

the whole car is juddering, the engine doesn't stall or get near stalling.

 

ahh you see now thats different, sound like the drive train or suspension, possibly engine mounts?

yeah, I don't really know why I used the word 'gas', must be looking at too many american forums!

ahh you see now thats different, sound like the drive train or suspension, possibly engine mounts?

 

Aah, that would make sense. The suspension has been knocking in the last week, I'm taking a look at it this weekend as I assumed it was a bush or something that had gone.

tbh i cant see why different ron fuel would cause the overfueling, it would just det on higher boost.

 

could be a temp sensor fault? you need to get it on conzult to see whats going on and change to higher ron fuel straight away!! if you havnt damaged a piston yet you will do at some point ;)

 

over fuel to protect the engine while under higher boost.