Technical help coupe overboosting and boost variating

[madmax127]

hi people, im new but i have a yellow coupe 2.0 litre 20v turbo, and when i put my foot to the floor from a steady speed from 2nd onwards it will variate from 0.5 to 1.3 bar and sometimes overboosts and will backfires. when it overboosts the engine light comes on. I put the vehicle on a examiner and it come up with airflow meter s.c to ground intermittant so i replaced the afm with a new recon part from fiat but it still comes up only when it overboosts not when it variates someone please help me ive being racking my brain for three months trying two sort this my mates at work are stumped. i think it mite be the pierberg valve faulty but not sure thanks max.

 

[alainax]

check out the fccuk forum, always helpfull

 

[pinin__prestatyn]

Hmm, could be your EBV is sticking. They do that. You could try cleaning it/buying a new one, or test a PRV/PBV on the car.


Did that make sense?

 

[dave]

i dont know a lot about turbos, but could a hairline crack in exhaust manifold cause it?

 

[sumplug]

Think this could also be the actuator on the turbo sticking. Easy to check though by making sure it moves freely.

Andy.

 

[alainax]

Asked "someone" for you, and he reckons you could have a faulty ebv or boost leak somewhere and the system is trying to compensate hence variation.... or something like that.

 

[mattB]

Your pierburg valve is toast. Get a replacement, or even better replace it with a manual/electronic boost controller.

 

[pinin__prestatyn]

And a chinchilla.

 

[mattB]

Indeed, they always come in handy if the windscreen gets fogged up or whatever.

You might also consider some of those yellow pointy things you see on the wheels of lorries.......

 

[pinin__prestatyn]

What are they for again? I'm sure someone's explained to me...

 

[Rampage94]

so if the lug nuts are loose they can tell right away because they wont be pointing at one another.

 

[madmax127]

thanks i do have a cracked manifold its going to be replaced with a banana bunch manifold and whats an i was thinking that two i think the i found my exhaust front pipe barcket that connects to th turbo very loose so i tightend it and the overboost is gone but it still variates so ill try a boost valve thanks for all your help this has buged me for months

 

[pinin__prestatyn]

Didn't know the Banana bunch did a manifold for the coupe!

http://www.bananabunch.com/the_artist.html

Still if there's money to be made...

 

[dave]

Didn't know the Banana bunch did a manifold for the coupe!

http://www.bananabunch.com/the_artist.html

Still if there's money to be made...

wrong bunch http://12121.hostinguk.com/splits.htm

 

[madmax127]

ha ha i ment 5 into one

 

[madmax127]

thanks for all your help ive replaced the ebv and the boost pressure has now stopped over boosting and variating