VVC Inlet & over size throttle body / idle problem

Chris G · 17th June 2017, 08:44

Hi

Since having a VVC aluminium inlet manifold with a 52mm throttle body fitted to my 1.8 Turbo I've been experiencing fluctuating idle & occasional stalling issues.
What I do know now is that the idle falls when there is too much pressure building in the manifold following a quick session with the lap top.

After a bit of fishing around it seems possible that the stepper in the IACV should of been re set..

Is this possibly the solution?
How is this achieved?
My car presently resides at a garage with T4 to hand.

.

Chris G · 17th June 2017, 08:46

Oh and the cam timing is fine. Already had that checked.

suzublu · 17th June 2017, 12:50

First thing to try is to turn the ignition on, then press the accelerator pedal 5 times in quick succession. turn off, then restart. Alternatively, using a T4, you can adjust the IACV screw on the throttle body, you may have to remove the plastic cover to get at it.

sworks · 17th June 2017, 13:23

Pretty much as above except I didn't think you could change the throttle body on the turbos as the standard units had extra sealing due to boost pressure?

Avulon · 17th June 2017, 15:18

Interesting - I also have a vvc manifold on our 1.8T tourer, There's no idling problem, but I always feel that the engine has a stutter on pick up - even with the turbo spooled up. Is this IACV screw adjustment something to look at? what is IACV?

suzublu · 17th June 2017, 15:50

Quote:

Originally Posted by Avulon

Interesting - I also have a vvc manifold on our 1.8T tourer, There's no idling problem, but I always feel that the engine has a stutter on pick up - even with the turbo spooled up. Is this IACV screw adjustment something to look at? what is IACV?

Idle Air Control Valve

Chris G · 18th June 2017, 10:02

Quote:

Originally Posted by suzublu

First thing to try is to turn the ignition on, then press the accelerator pedal 5 times in quick succession. turn off, then restart. Alternatively, using a T4, you can adjust the IACV screw on the throttle body, you may have to remove the plastic cover to get at it.

The pumping pedal 5 times thing I have tried.
Apparently all this does on a 75 is re set the throttle position sensor.
So T4 is fingers crossed the way forward.

After that.. I'm stumped.

Avulon · 18th June 2017, 14:07

Quote:

Originally Posted by suzublu

Idle Air Control Valve

Of course, thanks Ronnie.

So it's not going to have any effect then at part/full throttle openings then.

Save

Chris G · 20th June 2017, 09:02

SO..

Will the standard throttle body fit the VVC?

suzublu · 20th June 2017, 09:11

Quote:

Originally Posted by Chris G

SO..

Will the standard throttle body fit the VVC?

It's what I have

17th June 2017, 08:44	#1
Chris G Newbie Rover 75 Saloon Join Date: Oct 2016 Location: Worcester Posts: 28 Thanks: 2 Thanked 1 Time in 1 Post	VVC Inlet & over size throttle body / idle problem Hi Since having a VVC aluminium inlet manifold with a 52mm throttle body fitted to my 1.8 Turbo I've been experiencing fluctuating idle & occasional stalling issues. What I do know now is that the idle falls when there is too much pressure building in the manifold following a quick session with the lap top. After a bit of fishing around it seems possible that the stepper in the IACV should of been re set.. Is this possibly the solution? How is this achieved? My car presently resides at a garage with T4 to hand. .

17th June 2017, 13:23	#4
sworks Been absent for a while… Rover 75 Tourer, Classic mini Cooper S, Abarth 595 competizione, MG TF and a Hyundai Tucson PHEV Join Date: Feb 2007 Location: Cumbria Posts: 13,072 Thanks: 1,033 Thanked 1,686 Times in 1,040 Posts	Pretty much as above except I didn't think you could change the throttle body on the turbos as the standard units had extra sealing due to boost pressure? __________________ ................................................. 'Marmite' Possibly one of the most famous 75 tourers produced! left the production line as the last of only Three Rover 75 tourers produced in Trophy Yellow. 48 hours later Longbridge closed. The last sold ordered 75 Tourer. Paid for by the Phoenix Four and handed over by John Towers to the Warwickshire Northampton Air ambulance service as a Rapid Response vehicle

17th June 2017, 15:18	#5
Avulon This is my second home 1.8t Tourer Join Date: Oct 2011 Location: Tanelorn Posts: 4,830 Thanks: 956 Thanked 1,148 Times in 916 Posts	Interesting - I also have a vvc manifold on our 1.8T tourer, There's no idling problem, but I always feel that the engine has a stutter on pick up - even with the turbo spooled up. Is this IACV screw adjustment something to look at? what is IACV? __________________ Need a T4 ?: T4 Owners Map thanks to Stevestrat ( use at your own risk) Where?: https://en.wikipedia.org/wiki/Tanelorn Mods/Retrofits: PCV vortex 'filter'; bluetooth; inline thermostat; reversing sensors; plenum spyhole ; headlamp washers ; Diy mp3 player replacing CD multichanger; FBH with remote; Headlamp washers; black/chrome front grille, rear blind; Xenon projectors To do: puddle lights; 2 Din cd/nav to fit; boot release button

17th June 2017, 08:46	#2
Chris G Newbie Rover 75 Saloon Join Date: Oct 2016 Location: Worcester Posts: 28 Thanks: 2 Thanked 1 Time in 1 Post	Oh and the cam timing is fine. Already had that checked.

17th June 2017, 12:50	#3
suzublu This is my second home rover 75 1.8 vvc club se wedgwood blue Join Date: Aug 2009 Location: Seaton Carew Posts: 26,955 Thanks: 65 Thanked 7,142 Times in 4,642 Posts	First thing to try is to turn the ignition on, then press the accelerator pedal 5 times in quick succession. turn off, then restart. Alternatively, using a T4, you can adjust the IACV screw on the throttle body, you may have to remove the plastic cover to get at it.

20th June 2017, 09:02	#9
Chris G Newbie Rover 75 Saloon Join Date: Oct 2016 Location: Worcester Posts: 28 Thanks: 2 Thanked 1 Time in 1 Post	SO.. Will the standard throttle body fit the VVC?