Petbeemer

Hi peeps, im in need of some knowledge from veterans on here, i recently bought a Bugeye wagon N/A for the Mrs, now when we picked it up it did have the cel light on which i thought would be something and nothing (i own a Scoob garage) what a mistake!
Symtoms are:
When driving when you fist put your foot down there's a 'lul' where it doesn't seem to do anything until the throttle is depressed more and then picks up with a sudden 'jolt' and drives normal, but then seems as if the revs have caught up with the amount of throttle you've first give it then dies again, if you then put your foot to the floor it kicks back in again with a 'jolt'

First job was to reset the ECU and clear the CEL light, which it did, next i scanned it to see if there was any codes stored from fresh and there isn't
ive ran the logger on it and all seems to be working fine, the only doubt i had was the crank sensor which i changed out for a good known working one, i then went for a drive and thought it had cured it as it seemed to drive fine, but after 10 miles or so it's back again and doing the same thing, logger plugged in again to check and all seems to be ok but i noticed while stationary if you try to pick the revs up to around 2k it starts to missfire and run really lumpy until it gets to around 3k at which point it revs clean again, the logger shows no real difference in this area though?

Changed the MAP sensor and throttle position sensor, lambda sensors both seem to be working correctly and i have MOT'd it recently which it passed on emissions so doubt it being that side

Any idea's people?

dunx

iTrader: (3)

Morning,

the nearest experience I've had was a pal's WRX that did this, it's a lambda sensor slowly dying.... ( IMHO ).

They don't throw a full fault code till they get far closer to death.

But don't spend any money yet, let it die and then replace it ?

or it's nothing to do with it !

dunx

al02uk

iTrader: (1)

+1

Sounds like the lambda sensor

Petbeemer

Thanks for the reply
However Lambda was in range on MOT and that was while the symptoms were there, in fact emissions were very good so sailed through

al02uk

iTrader: (1)

Mine was the same,

Passed MOT easy, with an advisory for the CEL. Changed it shortly after reading on here and all was well

Petbeemer

I'l give it a try then, can't hurt

dunx

iTrader: (3)

Only the wallet, give it some time and it will get worse to confirm the diagnosis...

dunx

Petbeemer

Well it's almost undrivable at present, around town anyway so will need to be sorted asap

Petbeemer

Just to clarify for those that use search
The delay in throttle responce was actually the TPS (throttle position sensor) out of adjustment, for why i have no idea but previous owner must have fiddled, it showed on the logger (romraider) as a value of 0 until around 1/4 throttle was pressed then a raise in value as it was supposed to do, reset this so it registered 0 on idle but with a rising value as soon as the throttle was pressed and it worked a charm!

However

The CEL light on the dash was indeed the lambda sensor, theres 2 on the N/A the first is a wideband version the second is a normal 4 wire lambda, mine strangly looked like it had been hammered to death so was easy to diagnose as shagged! i only had 3 wire sensors to hand so after looking at the wiring diagram realised that 2 wires are heater circuit 1 is signal and the other is ground, so i used the 3 wire sensor and just earthed the ground on the side of the sensor, reset the ecu and no more CEL, checked with romraider and both sensors working well!

Still getting sh1te mpg though around 35 miles for £10 :-0

nick172sport

iTrader: (6)

not right that should be more im getting 30 miles to gallon and mines a turbo

Petbeemer

I know but i have a rear caliper that seems to be sticking also so until i sort that as well i can't judge

richgreenscooby1

iTrader: (2)

my missis only doing 34mpg tops . same car

Petbeemer

not very good mine then only getting 35miles per £10 of fuel

richgreenscooby1

iTrader: (2)

have you sorted the missfire now ?

Petbeemer

yep have a look above at the previous post, all sorted