16V Throttle Body

The 16V Throttle Body (TB). Like any other engine this one chokes up with crap. The TB on these gets fiddled with by idiots, it shouldn't be touched. So if you think you can adjust out your idle problems by tinkering with it - DON'T!

The TB is set from the factory and will not need setting again.

Anyway, you need:

Flat Screwdriver
T40 Bit
Carb/Brake Cleaner

Start by removing the air filter to TB pipe from the TB. Use a flat screwdriver on the jubilee clip. This can be awkward to get off so watch you don't hurt yourself.

Remove the throttle cable from the TB, open the throttle by hand then slide the cable out.

Then you need to remove the 4 T40 bolts that hold the TB to the manifold.







When you remove the TB, the gasket may stick to either the TB or the manifold, here it's stuck to the manifold.



This is the TB on removal, front view. That's how clean you want it by the way!



Back view, you can also see where the idle bypass screw's exit is, up the top.



This picture shows the Throttle Position Sensor (TPS). This should not be touched! It also shows the TB heater wiring plug, not on all TB's!



This picture shows the TB Heater, it's made by Pierberg in case your interested. Most engine looms don't have the wiring plug for it so its a pretty useless thing to have.



It's held on by 2 T20 screws and there should be a paste like that used on PC ECUs to Heatsinks between the TB and the heater's body. That is if it's even used or you want it perfect.

This next picture shows the throttle plate bypass screw, this should be under an Anti-Tamper Cap, in this case this TB was fiddled with before I got it.

Screw removed.....



Where it is.....



In the above picture if you look closely this TB is missing the throttle stop screw (top right).

This picture shows the throttle plates open, it's nice and clean. It also shows where you can remove material to improve the flow through the TB.



Righty, basically blast it clean and that should be it!

But what if some muppets has arsed about with things?

Well you need to try and sort that out.

First things first, the throttle plate position. If the screws missing get another and put a lock nut on it so it doesn't move. Snap the throttle shut a few times to centralise the plate. Hold it up to a light source. When it's correctly adjusted you see a ring of light around the plate. Adjust it to that - not a big gap, a slight gap; similar to an eclipse of the Sun.

The plate bypass screw. If it's been messed with then remove it and clean the channel out with cleaner and a cotton bud. Screw it back in right the WAY IN and leave it there.

Start the engine and see where it idles, this should be pretty close to normal.

Block the Idle Control Valves pipe to the manifold. The natural idle should be around 950rpm +- 50rpm. Although there is a good chance it will stall if the plate is still dirty.

This is called the 'Base Idle Setting' by the way.

When this is set, unblock the ICV pipe and the idle should remain the same or if it's a touch low then it will increase to around 950-ish rpm.

Rev the engine and make sure it settles back to a nice idle, which it should.