Erratic acceleration when pushing hard

=|[PsychoPoet406]|= · Post by **=|[PsychoPoet406]|=** » Tue Jul 18, 2006 8:15 pm

Still no closer to solving the mystery of my car's weird performance. The car generally goes fine, if a bit rough on startup (especially in this heat), but there is still something of a flat spot around 2000rpm which only tends to occur when I'm driving fairly hard. I don't have any problems while driving like an old man.

However, the other night when coming home I quite rightly decided I wanted to enjoy myself on the way home. I wasn't driving like a berk or anything but I did accelerate hard through the gears on a duel carriageway. Suddenly the engine became very rough and spluttery, jerky and juddery, generally powerless and unpleasant to drive. It sounded like a plug was loose again, but the engine seemed fine when I got home. The car was acting normally the next day.

What could be going on? My last 406 saw some serious abuse (a lot worse than I've given Defiant) and didn't so much as suffer clutch slip!

Post by **Foxy** » Tue Jul 18, 2006 8:48 pm

Sounds like your engine is broken. Buy mine!

=|[PsychoPoet406]|= · Post by **=|[PsychoPoet406]|=** » Thu Jul 20, 2006 5:03 pm

I might buy the head from your car depending on what the experts say when I have my car re-diagnosed (the third diagnosis in 3 months!).

Post by **Foxy** » Thu Jul 20, 2006 7:17 pm

Well let me know soon. You might as well take the whole engine/shell. Im sure I can arrange a good price

Post by **niz406** » Fri Jul 21, 2006 12:12 pm

Sounds like you want it gone foxy ! ! lol

Post by **nick** » Fri Jul 21, 2006 12:44 pm

Have you checked the Coil Pack?

Post by **Welly** » Fri Jul 21, 2006 1:17 pm

I would start with a compression test, and a test on the coolant to make sure no hydrocarbons present (head gasket).

Once you know the engine is sound then the problem should be something simple like an Ignition fault, or vacumn leaks or hose leaks etc .

Almost sounds like boost creep where it is overboosting and cutting the fuel, or even a faulty Turbo actuator letting go.

But it would be sensible to start with the core mechanics of the thing.

=|[PsychoPoet406]|= · Post by **=|[PsychoPoet406]|=** » Fri Jul 21, 2006 7:08 pm

It looks like the exhaust valves really are gone. The engine is "running like a bag of nails" as the mechanic said today, and the timing seems to be out again. My dump valve has also packed up - it's stuck open so the car can't produce much boost! I've only had it two months!

There's a 306 GTi-6 going cheap nearby so I might well ditch my 406 and buy that!

Post by **niz406** » Fri Jul 21, 2006 7:17 pm

if you ditch... it swap BOV's with me

lol

Post by **nick** » Sat Jul 22, 2006 2:33 am

if ur jus gunna ditch it, give me a shout. lol

Post by **Foxy** » Sat Jul 22, 2006 9:52 am

So do you want this head I have?

Speak to me before you buy the 306, Ill give you some pointers on what to look for.

=|[PsychoPoet406]|= · Post by **=|[PsychoPoet406]|=** » Sat Jul 22, 2006 5:35 pm

Sorry for mucking you about Foxy, I keep getting distracted. I am probably going to buy your 406 head. My main problem so far has been money - I was badly overdrawn last month. (Pesky long-term illness meant I was unable to work for the whole of last year.)

This sounds stupid, but what is actually in the head? Cylinders, spark plugs, valves/springs, pistons? How much is it going to cost to get the heads swapped over?

Post by **Foxy** » Sat Jul 22, 2006 9:07 pm

The head contains a camshaft, 8 valves and a pulley. Thats all you need to know really.
I have a potential buyer who wants the whole car left overs. hes willing to pay big bucks as well so be quick. (im not just saying that lol)