325i sport throttle body

[janc]

Help required. I am looking for a 1990 325i Sport throttle body. When looking around I haven't seen one the same. Mine has a brass pipe that sticks out the bottom over which a rubber cap fits. Are those without this the same? I mean can I get one without to replace mine and what is that pipe for bearing in mind it is fitted with the cap? Any information as to the difference is great appreciated. Thanks in advance.

[Cloggy Saint]

The pipe on the bottom goes to the charcoal cannister if fitted. If not it has the rubber cap on it. If you don't have a charcoal cannister you can fit either throttle body.

[janc]

Thank you for the information what is the charcoal cannister for? I don't have a cannister fitted. I presume it is to capture waste oil? Do many cars have this?

[Cloggy Saint]

It's part of the emissions sytem but I don't know exactly what it does. Something along the lines of filtering the fuel vapours I think but it's not essential.

[janc]

Thank you, I don't think I have ever seen one. Thats a relief, as looks like I need a new one as the bolts on the side cooling system have sheared. Try and drill out but they are really small bolts. Steel an alloy don't mix.

[Brianmoooore]

It's not a cooling system, it's the exact opposite - a heating system, and even where you live, it's unlikely to be ever needed.
Disconnect it and join the two hoses together, or invest in a single piece of new hose to link together the two stub pipes on the engine that feed it, and release a very small extra bit of engine power.
If you do still want to replace the TB, all M20B25 ones will do - there's nothing different about a 'sport' one, or any other bit of the engine, for that matter.
TBH, I'm surprised you have one without the stub pipe for the fuel tank vent system. I thought all 2.5 engines were "emissions equipment ready", so should have the stub, even if in most cases it's unused and capped off.
The only significant difference you might find is that early TBs have two stub pipes leading to the brake servo, and later versions have one. If you replace a two pipe one with a single version, a simple small mod has to be made to the servo vacuum pipe plumbing.

[janc]

Hi i do have TB that is capped off with rubber cap. With a single pipe to the servo. Took off to clean up and check TPS. Decided to renew the gasket on the heating system and ended up snapping one of the bolts after a prolonged soaking with WD40. So have been. Looking foe a replacement. But haven't come across one with the pipe connector on the bottom, mine does have a rubber cap. Thank you for the information about running a single pipe.

[Brianmoooore]

But haven't come across one with the pipe connector on the bottom

??? The pipe connector for the carbon canister? I've never seen one without, although in most cases it's capped off, or at least, should be.