On my home this afternoon I overtook about 4 slow moving cars on a long open stretch of road. As I started overtaking the car seemed a bit down on power. I put this down to it being a hot day and that I was in fourth (hadn't needed to change down). As I accelerated past the traffic there was a sudden surge in power and acceleration which took the car back to it's normal performance. It was almost like really, really bad turbo lag.
Does anyone have any ideas what might've caused this?

While I'm asking - I want to make sure the car's running okay (runs great but is it about to blow up??? ) as I recently added the PPP ECU. It's been for a service since I put the ECU in; would this've shown up any problems or do I need to put it on a rolling road etc etc to be sure?

The car's an MY00 PPP with a magnex centre and scoobysport downpipe. It's also got an ITG, a P1 intercooler and a Forge recirc DV.

 

Get a boost gauge to confirm, but it sounds like boost oscillation caused by the decat/PPP combo. If it is, just open out the restrictor by .1mm.

Richard

 

where is the restrictor located on a my00?

 

I'll send you a picture

Tony

 

Thanks for that Richard

I have a defi boost gauge but I must admit I wasn't looking at it at the time as I wasn't expecting anything odd It regularly boosts to 1.25 in the warm weather and coming home on the motorway last night/early morning the limit light (set at 1.35) was flashing away merrily.

I thought the prob with the decat/PPP was the possibility of overboost? This certainly wasn't overboost but like I said, really really bad lag followed by all the power arriving at once

 

You'll probably get oscillation as it gets colder - wildly over target, then wildly under, and so on.

When it becomes an issue, do the restrictor.

Richard

Edited to add: Re. PPP/Decat problems - it's not overboost as in hitting fuel cut, but is overboost as in, well, going over the boost you wanted. It's caused by the reduction in backpressure.



[Edited by dowser - 8/16/2002 7:03:36 AM]

 

Great stuff thanks for that

 

I have the same problem on a my95 withh PPP ecu with decat. where is this restrictor located.

this normally happens on the motorway the boost drops down to 0.5 bar for a while and goes back to 1.1 bar after a few minutes, or if i switch off the engine and start up again to cures it ?

is this the same prob ?

 

I had a similar prob with my UK300 - it turned out to be the knock sensor - Prodrive said it was too sensitive where it was - and needed moving to a different place ???

fixed my problem - and car is running sweet as a nut !

 

Carpet - maybe they relocated it to the bin?

Richard

 

Sure you haven't got the same problem, but I had similar symptoms in the run up to each of my 3 engine failures since November last year (see dealer section). I am on engine 3 now (after ECU, Short Engine, Injectors changed under warrantee). May be worth getting the additional devices to check for boost/fuelling problems...just incase. (I had a faulty ECU ((UK MY99)says Subaru)), only ever encountered in Europe and not the UK..!!)

 

This sounds like my problem to me?

http://www.scoobynet.co.uk/bbs/thread.asp?threadid=122171