NelsonUK

I have been running a MY00PPP Decat now for a number of months without major incident. However with the colder weather we have been experiencing I have noticed the Scoob has felt a bit lucklustre at times ?? This week especially it has felt as if the cars performance has been getting worse day by day. Tonight travelling home from work was the worst I am finding it difficult to get any + boost in first and then there is hesitation (like lag) when using WOT in 1st, 2nd and 3rd. I have felt a slight shudder once or twice when this has happened and it just feels as if the car is not at full boost (even though the boost gauge says differently) The throttle pedal seems to be quite unresponsive and heavy Anyway travelling back tonight I also noticed that if I put my foot down to give me about 4-5psi of boost the AFR Gauge continued to swing back and forth between rich and lean, it generally usually swings into the rich zone as soon as I get any positive boost. If I then pressed the pedal to the floor it would swing into the rich ? This happened in 4th and 5th gear. I thought the problem might be MAF (it was only replaced at the beginning of the year) but having done the unplug whilst running the engine spluttered and coughed and tried to cut out until I plugged it back in.

Anyway having got home I performed an ECU check - no CEL so I did a reset. Former glory appears to have been restored ? Throttle pedal nice and light - 1st gear very easy to get onto boost and the car feels a lot more eager.

So any ideas what could be wrong ?? Is it a case of the PPP ECU overboosting cos of the cooler temps ? I am beginning to resign myself to the fact that I might need to stick the cat back on - Just to say I am running a Scoobysport Open neck Decat Down Pipe, Ninja resonated Decat centre and a H&S Scoobysport BB. I also have the brass restrictor drilled out to 1.3mm

Any thoughts or advice would be most welcome

Roojai

I'm no expert but I doubt it is due to cold weather, or the decat. Sounds more like something is wrong with your coils/spark plugs/intake tubing/injectors/fuel pump....

NelsonUK

Thanks for your input Roojai - Sparkies NGKPFR7's were changed about 7K miles ago - I bought new Magnecor leads for the car approx 18K ago. I have an uprated Walbro fuel pump ?? As for the intake and or injectors ?? not sure. The thing is having reset the ECU it feels good ? I am gonna be trying a Standard ECU in the car with the Decat over the weekend and this might help to see whether the PPP and Decat is the cause.

NelsonUK

BTTT any ideas ?

JIM THEO

As above and fuel pump as one more possibility!

The_Judge

If resetting the ECU fixed it, I suppose it could have been some major knock correction, possibly due to the combination of PPP advanced timing, full decat, and cold weather...? Could even have been reduced advance multiplier.

Can you think of any "incidents" that have occurred recently, that might have caused this? Dodgy fuel, excessive knocklink activity, etc...