I've just fitted a gtec 2 chip - all seems well apart from some eratic boost issues in the higher gears. My old chip used to keep the boost at 1 bar, and all was well, but the gtec 2 seems to see saw from 1, to 1.5 on full throttle and lower revs in the high gears. If I floor it at 4000 RPM or more its fine and holds the correct 1.2 bar boost. Does this sound like my EBV is on its way out?

Thanks

the ebv can be a little erretic, yes.....

I had similar with a standard setup, id describe it as a pulsing of boost.
was the ebv.
gave it a clean and was a bit better, but sorted by fitting a prv.

as above its your EBV, I tried cleaning mine and it did nothing. Best cure is by whacking a PRV on there

How do you set up the prv?

Guide for PRV/PBV installation:
http://www.coupe.v666.co.uk/fitting_an_armval_bcv11_prv.htm

Fair enought a prv will stop the problem, but doesn't it indicate something else is wrong
Also, doesn't a prv give you kind on/off boost, making throttle control a bit more difficult?

If the EBV is the cause of teh fault a PRV will solve it, both are boost controllers.
Regarding the on/off boost characteristic, you'll get used to it.

the problem is is that the ebv is sticking, replacing it might sort it also.
People refer to the dodgy italian electrics being a cause, arnt most of the electrics bosch though?

Almost all components are Bosch. Italian wires perhaps?

I'll try cleaning the ebv, and let you know if it makes any diffrence...

The PRV isnt totally on off... i find it kicks up to 10-12psi if u are tapping it then if ur full throttle then its the full whack u get! U do get used to it!

Ross

This happens on some cars (with either gtec1 or 2) due to the way the ECU controls the EBV being "lazy" and not responding quickly... it's because I'm trying to keep the overboost as low as possible (therefore quite close to the sustained boost level), if the boost overshoots it's target value then it can end up "see-sawing" between the sustained and overboost values.

One solution is to make a custom chip with slightly higher overboost level (have fixed a couple of "see-saw" boost problems like that), so the ECU/EBV can settle between them and not "see-saw" up/down, or to just fit a PRV or electronic boost controller to set the boost level manually.

Fitting a PRV is overall a better solution 'cause it helps keep overboost down and gives a lot more consistent boost.