F115 2004 shutter sync

[BigKingy]

Hi,

I have no issue to sync 1/2 with 3/4 following the procedure, but I found 3 and 4 being quite far out from each other. I have read there are bypass screws (factory setting) on the shutter to sync 1 with 2 or 3 with 4. Can someone point me out exactly where to find them. I have been looking everywhere and can't find the screws.

Cheers

[boscoe99]

Rodbolt advises to use the updated sync and link procedures that are available for the F150. Otherwise, the procedures will be in the applicable service manual. You do have a manual I hope.

[BigKingy]

Yes I do have the F115 manual, there is no mention of air bypass screw. Only the sync and link procedure between 1/2 and 3/4.

Cheers

[fairdeal]

I think he is asking how to do something which is stated as not able to be done....

[rodbolt17]

o but it can be done on an F115.
with the air box removed look on the inboard front of the intake. there are 4 air bypass screws.
play with them at your own risk.

[99yam40]

I thought they were not to be messed with after they were set originally.
if someone jacked with them and only then should they need resetting.

if something else has changed ,you need to find out what that is
but then I know very little about this, so do not let me sway your decision

[rodbolt17]

that is why a link and sync is supposed to be part of the PDI. I have seen a few so far off they would barely run out of the box.
my personal 07 F150 would stall at low speed maneuvering and it took me about a half a day to figure out how to fake the ECU and close up the ISC opening request.
Yamaha finally put the info in a tech bulliten a few years back.
and remember, it is a screw.
if something don't work move screws.

[BigKingy]

Thanks for taking the time to look into it guys. Rodbolt I couldn't find the screws you described so I did a bit of research. I think the air bypass screws were only on the throttle body 68V-13751-00-00 from the early F115 in 2000. It has been superseded in 2001 by 68V-13751-01-00 which doesn't have the bypass air screws.




So I have my answer, it seems impossible to adjust 1 with 2 and 3 with 4.

I borrowed a better gauge to check the sync and it seems to be within the tolerances of the manual (pic attached)

[BigKingy]

What would explain #4 to be lower then other cylinder? weak valve spring?