New Di - reduced performance

[AL900S]

Hi
2001 lpt auto (unmodified)
On Friday I took car to the dealer for the DI cassette to be changed as per service campaign. There is now a noticeable decrease in performance - it just feels less responsive to throttle input especially in sport mode from a standstill and a blip in power at around 4k revs on full throttle. On the old Di, it used to take off like a scalded cat with noticeable boost from 1800 with no hesitation at higher revs. I reckon the new Di may be faulty...however, I've heard that new plugs should be used with a new Di. My plugs have only done 500 miles. I'm booked in on Monday for them to take a look. I hope they'll replace the Di with another new one to see if the performance comes back. However, I don't want to get fobbed off by them saying that there's no problem or it's a problem I had already to get out of fitting another Di. I'd rather they refit my old Di than drive around with this 'new' one in. I hope it's not been binned.....

Any advice? could the fact that the new Di has not been accompanied by new plugs be the problem? or is it more likely that their 'new' Di is faulty.
Cheers
Al

[DrBoost_1]

Hej !

There is a possibility that you will feel different kind of symptoms after having fitted a new DI. This should however disappear after a while, as soon as the engine management has performed an adaptation. Normally you should see a change, to the better, with in ½ hour of normal driving. Mixed load/rpm. Your plugs should just be fine, keep them.

As you wrot, there is a slight possibility that the new DI operates outside spec's limits.

[AL900S]

Thanks Dr Boost

After noticing the lack of performance, I disconnected the battery for an hour and then took to the motorway for a blast of about 20 miles. However, the car still seems to lack power and generally feels 'heavier'. I'll see what the dealer says tomorrow and hope they'll swop for another new one or return my old one.

I've opened the bonnet and noticed that the dealer must have removed the positive lead but maybe not the negative whilst changing the Di. I can only summise this as the positive terminal has dents on it....they must have hit the postive lead quite hard in order to get it back on. No marks on negative though. I would have thought they'd remove the negative as per Haynes manual instructions?? or doesn;t it matter?

Cheers
Al

[AL900S]

Well, dealer just hooked car up to Tech 2 and said there were no faults and that after more driving, it will improve. Surely disconnecting the battery for a hr and spirited motorway driving for 20 miles would have done that already? or does it really need more 'driving'? Anyway, going back on Weds for them to 'go over it in more detail'. I'm still insisting on a new Di though.

Cheers
Al

[crashtestv6]

HI..

THOUGHT YOU MAY LIKE TO KNOW , WHEN ANY POWER SUPPLY LOST TO ECU, SOMETIMES, NOT ALWAYS MIND, THE ECU WILL LOSE ALL LEARNED PARAMETERS AND READINGS FOR ENGINE SENSORS ETC.. WHAT YOU WILL NEED TO DO IS DRIVE ABOUT HALF HOUR APPROX, AT VARYING SPEEDS, JUST YOUR NORMAL STUFF, COULD BE POSSIBLE THAT YOU BLASTED UP MOTORWAY, AND ECU ONLY RECOGNISED THOSE CONDITIONS AND SET IT UP FOR THAT.
I KNOW THIS, AS IT HAPPENED TO ME WITH A V6. AFTER BEING LAYED UP FOR 2 MONTHS , AND ATTEMPTING TO RESTART , BUT BATTERY HAD FAILED. RUN LIKE A BAG OF SPANNERS FOR A BIT , BUT EVENTUALLY SORTED IT SELF OUT.
STILL COULD BE POSSIBLE THAT THEY HAVE FITTED A DUFF DI, YOU MIGHT JUST BE UNLUCKY.
HOPE THIS HELPS....

[AL900S]

Hi crashtestv6

Thanks for that. I decided to disconnect the battery only after realising that all was not right. Since disconnection, I've driven to work and back a few times so I guess the ecu should have relearnt by now. They'll probably tech 2 the car tomorrow and check the hoses and tell me it's ok. They insisted on 'giving the car a good going over' ...before swopping the Di for another. I very much doubt they'll do that though. Seems simple to me...before new di car runs fine, after new Di car not running fine = swop di with another to see if that makes a difference ....not bugger about trying to avoid it!

Cheers
Al

[AL900S]

Well, back to dealer at 8am and they've fitted new Di...and surprise, surprise...the car runs great now! This Di now actually looks new and this is the VERY, VERY worrying part. The 'new' Di they fitted last Friday looked nowhere near as 'new' as this one...it was bubbling under the dull black paint in places. So, did they fit a used Di instead of a brand new one?.....if they did I'm lost for words...apart from expletives.

Cheers
Al