I just bought a seat of Bosch III injectors from southbay to replace the leaking stock injectors in my 305 tpi. I was wondering what else I should replace or what other maintenece to do while I've got the plenum off. I'll be replacing all of the gaskets (obviously) and I'm going to clean up the runners and plenum really well with some TB cleaner. What about the fpr diaphragm? Mine is original. Do they commonly fail or is this a good thing to do as preventative maintenence while the plenum is off anyway? I've never had the plenum off before so I welcome all suggestions. Thanks.

 

When I re-did my TPI, I made sure that I had new O-rings for the fuel rail assemby. I replaced my diaphragm with a new one. It's made of rubber so you figure with 20 years of cycling it may be getting weaker. Also, clean out your IAC valve. When you clean it, made sure you just spray carb cleaner with the sensor facing down. You DO NOT want any cleaner to get inside the housing. Just spray enough to get the gunk off the probe that sticks out.

You'll also want to get new O-rings for the connection where the fuel rail meets with the steel lines at the front part of the engine. I ripped one easily last time I had my TPI off.

 

I've got all the o rings for the fuel rail, they came with the injectors. Hadn't thought about the o rings for the line to rail fittings but that's a good idea. Thanks!