Fuel Cut, MBC, 1 BAR, I wish it would....

**wright_t5** · Monday 23rd May 2005, 06:31

Hi All,

I am back again, long time away, no problems so now news, except......
You mmay remember a while ago I had a turbo boost problem, where the ol gal boosted, then dropped off, then boosted again... well that never went away...
I have since fitted a manual boost controller, and tried to wind the thing up to at least 1 bar.... but no, I think it actually runs less than one bar now, and man does it hit fuel cut!!!! that boost problem I was having was fuel cut

How do you guys out there run 17 PSI with a manual boost controller, and not have fuel cut problems, or maybe it's me with a fuel cut problem....

Start talking you guys... oh, and gals... thinking of one in particular

**volvotuning** · Monday 23rd May 2005, 10:13

In a nutshell, I don't think it's possible to do on a T5, certainly not reliably. Many people fit an MBC for faster spool-up, but Hamish proved on the drag strip (against Pedro) that a T5 with an ECU upgrade can launch faster than one using an MBC. The MBC "feels" faster because the power delivery is very brutal, but an ECU upgrade is actually faster and doesn't have any fuel cut issues.

Adam.

**wright_t5** · Monday 23rd May 2005, 10:37

Interesting you have said that, I have already a "upsolute" chip fitted, and still get this surging problem,

Do you think you (VT) can do anything for me and improve things?? or do I just live with it...... I would like to get a bit more out of her, but have I already gone too far down a parallel road!!!!

I do tend to agree with your first comment though, the old gal ran smoother in standard trim, although the spool up now is much better... live is a compromise!!!

**volvotuning** · Monday 23rd May 2005, 10:59

Does it run ok without the MBC?

Adam.

**wright_t5** · Monday 23rd May 2005, 11:45

Well, not really, I think I am still hitting fuel cut, it's just that the electronics of the T5 smooths it out so it feels like a surge, rather than a "bang" I notice a difference now with the cruise and the MBC the throttle surges now and is not soo smooth, so all in all I am gonna remove the MBC.

I was coming to see you guys once before if you remember, but my auto box went bang 10 miles from your place!!!!!! I was coming for you to have a look...

I fitted the MBC to see if it made a difference... it did, and proved something... I have a problem......

I would like to get it sorted, although a point is that in sports mode it seems ok!!! very strange, does the sports mode push the boost level higher? or does it change the fuelling??

Do I need a new fuel pump maybe?, is the pressure too low maybe?? all these questions.... and no answers....

**volvotuning** · Monday 23rd May 2005, 12:03

Yes I do remember. A little unfortunate to say the least. Probably best to book it in again to get it checked out.

Adam.

**wright_t5** · Monday 23rd May 2005, 13:00

Yeah, I think so too....

I lost a lot of confidence with her when the box went, dam that shouldn't happen to a Volvo!!!! but the new box is sooo much better than the tired old one, and I have given her an outing up the pod!!!, but I would like to get it running sweet.... sooo wait for a phone call, I will try and get it to yah sometime soon, work, location and hospital (Long story) makes when hard to nail at the moment... will try to arrange over next few weeks...

Pedro Fandango · Monday 23rd May 2005, 14:09

Originally Posted by volvotuning

Hamish proved on the drag strip (against Pedro) that a T5 with an ECU upgrade can launch faster than one using an MBC.

i didn't even know i'd ever raced him (i have been to sleep since then), out of interest when, where & what time did i get?

Pedro Fandango · Monday 23rd May 2005, 14:22

Originally Posted by wright_t5

How do you guys out there run 17 PSI with a manual boost controller, and not have fuel cut problems, or maybe it's me with a fuel cut problem

tbh i'm baffled how BT is doing it myself (& a few other people), for ages she used to hit the overboost at about 15psi (which is about the norm) but then i found a couple of air leaks, since then the overboost doesn't cut in till about 20.8psi & can't find any particlular reason why she's quite happy with the extra 5psi