Giulietta boost fluctuating

[LeighW]

My Giulietta (2014 1.4 MA 170) has developed issues with the turbo boost fluctuating. It's really annoying, and my local garage has given up. They've swapped the diverter valve to no avail, so before I head off to the dealer (please God no... ), I thought I'd try here.

No EML light issues, no codes, nothing showing on diagnostics, no apparent boost leaks. It runs fine, no misfires or anything like that, but it just won't hold boost. It boosts, backs off, boosts, backs off repeatedly. In slow driving, no problems at all, but use 50% throttle or more and it makes you feel seasick.

A couple of video clips:

Half throttle from 2.5k revs, then full throttle, 4th gear.

https://www.youtube.com/watch?v=dIcLIEW_1HA

Full throttle from 3k revs, 4th gear.

https://www.youtube.com/watch?v=m3I7TA9UiTM

[Ransoman]

I had a similar issue with my 2010 Multiair (one of many that eventually led to me getting rid of it).

This particular issue was solved by using high octane fuel but I was never happy that the issue was just "worked around".

Having done some research into this after getting rid (I have an interest in the multiair engine and have been keeping an eye on the community in case i get another one in the future), apparently many of the 1.4 Multiair engine's issues can be resolved by upgrading the Coil packs to those used on the 1.8 TBI (4c).

[LeighW]

Ransoman said:

I had a similar issue with my 2010 Multiair (one of many that eventually led to me getting rid of it).

This particular issue was solved by using high octane fuel but I was never happy that the issue was just "worked around".

Having done some research into this after getting rid (I have an interest in the multiair engine and have been keeping an eye on the community in case i get another one in the future), apparently many of the 1.4 Multiair engine's issues can be resolved by upgrading the Coil packs to those used on the 1.8 TBI (4c).

Thanks for the reply. I tried high octane fuel, it made no difference.

I've had it for four and a half years and over 30k miles, and it's been spot on until now. I'll look into the coil packs, thanks. Are they a direct replacement?

[Ransoman]

LeighW said:

Thanks for the reply. I tried high octane fuel, it made no difference.

I've had it for four and a half years and over 30k miles, and it's been spot on until now. I'll look into the coil packs, thanks. Are they a direct replacement?

Yes, from what I understand they just bolt straight on with no modifications needed. It seems to be a popular mod in the states (this engine is used in the dodge dart and the US spec Abarth 500)