UKPOC forums

So VRIS one is not opening. Not electrical, checked that. Think it might be vacuum. Swapped the little black pump thingy (sorry can’t remember tech name) it opened initially and does occasionally but 95% of the time it’s closed. Causing havoc at lower end it’s sometimes like trying to ride a bull in certain lower rev ranges.

So here’s the question, two part, what sends the signal to open the valve? What’s the best way of checking for vacuum?

Any other input welcome, many thanks

Hi Gav,could be a cracked pipe under the Intake manifold from the vaccum chamber
My Vris 1 doesn,t work but engine works A1 with no problems,you could try changing
the plug over from Vris 2 to Vris1 to check

Hi ya Kev. Done the swapping about, all good there. Only thing left is vacuum. She’s very unsettled in lower revs kangarooey, but superb when kept in high rev range and fine on motorway. I know the timing is out, my light decided it doesn’t want to pick up a reading so all I see is TDC no matter where I position coil. However maybe there’s something else going on there CPS

gav0067 wrote: ↑

Sun Nov 25, 2018 9:02 am

I know the timing is out, my light decided it doesn’t want to pick up a reading so all I see is TDC no matter where I position coil.

Just checking, have you shorted the TEN and GND pins in the diagnostic box when adjusting the timing?

mikenali wrote: ↑

Tue Nov 27, 2018 7:49 pm

gav0067 wrote: ↑

Sun Nov 25, 2018 9:02 am

I know the timing is out, my light decided it doesn’t want to pick up a reading so all I see is TDC no matter where I position coil.

Just checking, have you shorted the TEN and GND pins in the diagnostic box when adjusting the timing?

Yep, shorted the TEN & GND It was only a cheap light of eBay and I’ve had it quite a few years, probably just just decided it doesn’t want to play ball any more.

To sort out VRIS a mityvac is a useful tool. I did write a guide to fault finding the vris years ago, I will see if I can find it.

In my experience most problems are vacuum related, heat makes the tubing brittle.

To answer your other question, vris is opened by the ecu based on parameter set within the ecu.

For example the vris switching at 4000 rpm only happens in a wide open throttle state, if this doesn’t work, it is usually a TPS fault.

Between 0 rpm and 3250 rpm vris 1 and 2 are closed.

Between 3250 and 4250 rpm vris 1 is open, vris 2 is closed.

From 4250 and 6500 rpm both open, unless no wot.

Above 6500 both closed.

humph wrote: ↑

Tue Dec 11, 2018 9:24 pm

Between 0 rpm and 3250 rpm vris 1 and 2 are closed.

Between 3250 and 4250 rpm vris 1 is open, vris 2 is closed.

From 4250 and 6500 rpm both open, unless no wot.

Above 6500 both closed.

That’s some useful shit humph, honestly. However I was under the impression VRIS 1 opened as soon as engine fired up? I know both act differently according to throttle and rev range, which I suppose now makes it obvious the TPS is somewhat responsible for their actions.
Anyhow after a day with Kev (CPT Black) both VRIS are working and SBM is actually drivable. Culmination of silly little things, CAI dragging down the air intake to throttle body and float at MAF not functioning properly, oil breather bung on front rocker causing air to be dragged in and VRIS 1 vacuum being lost on regulator ( connector broken on entry point).
Just gotta get timing set right but I’m still convinced the TPS is not giving the right signals. I’ll see how she goes when timing is put back into place.
Cheers for the insight very useful

Will dig out my manual tomorrow and check.