O2 sensor??

[Bcox-vrs]

Hi guys was wondering if somone could shed some light on a situation I recently posted about fuel pump… 

 

I drive a Skoda Octavia vrs mk1 1.8t 20v running stage1 mods are 

fmic

K&n induction kit

full miltek exhaust

4.pot brembo brakes and some other small things. Anyways I have a problem where the car flutters and hits walls under acceleration. Even with throttle planted it doesn’t seem to go anywhere. If u rest your foot on the throttle it will slowly gain speed and revs but if you press any sort of weight on the pedal it instantly hesitates and pops out the exhaust. I cant seem to drive passed 2.5-3k without the car struggling even on idle it struggles to Rev to red line? It’s recently had the following and still no cure to the problem.

x4 spark plug 

x4coil pack

maf sensor 

n75 valve 

air flow temp 

Vac pipes due to vac leaks. 
fuel filter 

oil filter n oil change 

car is running rich as it’s stinks but has a code running lean bank1 and 02 sensor. The car had a decat fitted 3k miles ago (it’s not mapped in yet) and hasn’t had any other issues, this current issues I’ve had for around 2/3 weeks. I brought a 90deg ecu fooler that goes in the o2 sensor passed the cat. I was told it’s makes the car think it’s reading clean air so I haven’t got to map the decat in. This still hasn’t fixed the issues and I still have 02sesnor fault. What Could  be the cause of my problem I’ve had the fuel pump and injectors all checked and there fine and not clogged up. I have got a crack in the manifold of my exhaust but I brought the car like that several months ago (not had time to get round fitting it) I can’t see this causing the problems I have but your welcome to correct me. 
just to add I only use 99ron fuel E5 

 

thanks guys I know it’s a lot. I can send any videos if needed. Had it plugged in by a couple companies and no one can seem to fix the issues lol. 

 

[J.R.]

With the amount of modifications from standard, mods to fool the ECU, cracked manifold etc I doubt that anyone would want to get involved in fixing the issues without first reverting everything back to standard.

 

My contribution wont resolve your problem but hopefully may help you understand the rich mixture/lean O2 sensor reading conundrum.

 

If the Lambda sensor is telling the ECU that the combustion mixture is weak (probably as a result of the other bodges) then the ECU will enrichen the mixture to compensate and will continue to do so if the Lambda reading does not change, you have a closed loop circuit in open loop.