Throttle body adjustment - stopper bolt clearance?

P

PrimeraPowa

Member
Hi guys,

I'm just setting up a Pulsar engine after a swap and struggling to get the pairs of throttle bodies balanced equally.

I've adjusted the adjuster rods as per FSM and the best condition I can get to is the throttle stop for cylinder 3 & 4 to rest on the stopper bolt, whilst the throttle arm for cyls 1 and 2 doesn't full close.

The car has a high idle that I can't get lower than around 1800-2000 rpm - (idle screw is bottomed out and have changed the two idle valves and air regulator to no avail). There are no vacuum leaks either. The plugs for 1 & 2 have much leaner looking tips (brown colour) than the ones in 3 and 4 have, which are black, suggesting the two throttle bodies aren't balanced.

The throttle stop on the cyl 1 & 2 has this gap on them to the stopper bolt:



Whilst the throttle on cyls 3 & 4 closes fully onto the bolt:



I can't get these equal and am assuming there is something stopping the butterflies in the throttle for 1 and 2 fully closing.

Has anyone got any ideas on equalling these out?

Cheers

Ben
 
PobodY

PobodY

Moderators
Staff member
Any chance there's shite on the butterflies that are stopping them from closing? - I'm just thinking that if it's not on the outside of the throttle bodies, maybe it's on the inside.

It might be a bit of a long shot, but mine had a bit of brown build-up on them when I had the plenum off so I did my best to clean them without disturbing anything more than I had to.
 
P

PrimeraPowa

Member
Yeah that's what I'm thinking could be possible, the throttle doesn't close fully everytime by itself either, often have to push it the last millimetre of travel or so and causes it to idle high. I'll take the plenum off and have a look.

Going from the FSM it says you should be able to adjust both adjuster rods to get each plate to sit on the stopper rod, which is fine for the 3 & 4 TB but not 1 & 2.
 
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