My car has developed a very annoying fault.

On accelerating once the revs hit 2500-3000rpm the car misses a beat and then runs fine. Its like the power has cut for a fraction of a second. your foot is hard down, she picks up then dies and then lurches off again normally. Its not normal Turbo lag, its much more viscious than that.

I also notice the turbo boost seems to jump from 0.0 to 0.5, its like its not smooth. I am sure before the boost was a linear progression.

I did have alternator probs and the car came back from the shop with the radio needing its code again, so the battery was disconnected for a while. It seems this prob has happened since then..?

Any ideas is this mechanical turbo or is it the computer management. The car is as far as I know not chipped.

Ideas gratefully received

Carlos

 

With this and the sunroof post I would look it to a loose ground or weak battery.

 

How many miles? Mine was doing similar stuff at 28K and needed new plugs, which solved the problem.

 

Thanks for the replies.....Shes got 75,000, the plugs were changed sept last year. Can they go off in 9 months.

Going to check battery connections in morning.

Also I read I should measure battery ground by putting a volt meter between the neg battery terminal and the engine block to check the earthing, resistance should be zero, anyone had success with this?

Just to add the car was missing a bit when cold a couple of weeks ago, like when the choke on a car isnt working properly, this was only when cold and went after I was out of my 1 km street and on the road...this symptom has gone but now she dies for a fraction of a second, only once in a while..perhaps 3 times in a 30 minute drive.

 

Tested the battery and battery earth, all OK. Just been for a 2 hour drive and the fault is still there. There is a lot of talk of boost leak causing missing when accelerating. Mine now only boosts to a max of .5 and.6 when I really piush very hard. It was .7 regularly before so I may have a leak in the inlet system. There is another paralell thread on this site talking about how to pressure test the system DIY. I will post the link. I have a compressor so I am going to try this. Just not sure about access to all the tubes, guess pretty much all is underneath the car. More soon...

 

Heres the link.
https://www.6speedonline.com/forums/...ig-w-pics.html

 

Fixed it.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I was looking and looking on the internet for pics of where all the various hoses route and getting a bit tense at the akwardness of it all so I thought ill go and just stare into the engine bay and see if any pics match whats under the lid. As the car had had the alternator done before the trouble started I looked at the pipework around there. The first clip I touched to see if it would budge was the large one on the single end of the large y pipe and it just span around , not done up after the alternator job. WORSE still was the MAF connector fell off at the same time, not clipped in. No CEL warning light for any of this incidentally.

Anyway 5 mins later all done up and back on the road with a NEW car. My god, I cant believe I drove for 2 hours today and convinced myself all was only just a bit off. The power is all back and I am still grinning 30 mins after I parked her up. 0.7 bar on the boost, cricked neck, sweaty palms,,, all the things I love that car for.

Needless to say I am happy (not at the garage,grrr).

Thanks for all your input.

Carlos

 

It's good to hear that you got it all running back to normal. I had a similar problem with a bad MAF. A tricky problem to diagnose with a aftermarket flash.
My car spools up to 1.3 of boost. Talk about an adrenaline rush.

 

Glad it got fixed and you figured it out relatively quickly!

P.S. Sorry you had to settle for a draw yesterday!