Maintenance items while intake manifold removed

[Amalgam]

Just wanted to get a quick pulse check on what should be replaced while I've got the intake manifold removed (installing the Turner CSL box) - the car has 165,000 miles

Debating on the following:

TPS sensor (throttle actuator side)
Fuel Injectors (rebuild vs replace?)
Cam sensor

Anything else I should consider? Starter was replaced recently so that should be all set for a while.

[gabylonfive]

that's a pretty good list - also clean ICV and ITBs while they're right there. Replace dipstick o-ring and seal too since it's right there and you'll be moving it around during install. Good idea to double-check the bolt that holds the upper timing chain guide on the intake side - it can leak and potentially back-out. Here's a link to the bolt in question along with associated seal - https://www.bimmerworld.com/Engine/C...111736005.html.

[ATB88]

Welp if you're considering the cam sensor then why not also the crankshaft position sensor: it's kind down underneath where the throttle actuator is, right at the back of the block.

The following might be a good idea considering your mileage, for failure-proofing, and are cheap or free:

-O-rings on the throttle body<->air rail tubes isn't a bad idea for leak proofing (you'll need 24 of them, but they're cheap)
-O-ring on the fuel feed line where it mates with the fuel rail (watch out, this is not the same as the air rail tube o-rings, this one's thicker)
-First time I pulled my air rail I took all 6 air rail<->throttle body tubes off and let them sit in simple green for a few hours, cleaned out a ton of gunk they'd had on them even at 60k miles
-Order the PCV line that connects the bottom of your airbox to the oil pan. Yours may well be trashed/brittle/cracked at your mileage, or might even get damaged while removing the airbox it it's really old. Replace it if so, and if not just send it back for a refund. Make sure you order the right one -- it's a different part for 6MT vs SMG.

If you're reaaaaally going ham there's also the 3 knock sensors. From what I've read it seems like these very rarely fail (although I remember a thread from the old forums where Obioban's did once?). And they're also pretty cheap ($60 each on FCP), so depends on what you're trying to accomplish here.

For injectors I would personally replace with new Bosch from FCP ($45 each) over cleaning/rebuilding (typically about $20 each and is logistically more annoying because you have to send them out and wait for them to come back). There are lots of places that do a great job with cleaning but you might get unlucky, and for the price (and at your mileage) I think it really makes sense to go new.

[old///MFanatic]

You might consider those coolant/heater hoses. Or at the least the o-rings for those hoses since it's likely been moved around when they did the starter.

[Rhythim]

I'd look really closely at all the hoses for the IAC valve. Mine developed a vacuum leak a couple years ago (140K-ish on it) on the block side of the connector hose on top of the valve (13417837653) that I would have NEVER found without my smoke tester. Sucker was FIFTY BUCKS for a 2-1/2 inch long piece of rubber, but at least it was an easy fix once I found it.

[mrgizmo04]

With the box out you also have access to ps reservoir and some of the associated hoses to cooler/pump.

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