Cloveh

I recently pulled my UIM to get my fuel injectors cleaned and do my vacuum lines, which has rapidly spiraled into also rebuilding the OMP and lines, but I have noticed a large amount of carbon in the secondary intake tracts, which makes sense from the lack of fuel injected into them (the primaries have virtually none). I can actuate the 5th and 6th port actuators by hand with not a ton of resistance so I don't believe they are frozen due to carbon. If I can help it, I would prefer not to remove the LIM due to the extra effort it would take to remove and reinstall. Should I clean out the carbon deposits or is it not worth it? If so, what should I do to remove the carbon? The motor ran great before but I don't know if the 5th/6th ports were actuating as I never tested them.

j9fd3s

iTrader: (3)

clean what you can, i wouldn't worry too much about it though. carb/brake cleaner works well

LongDuck

Its not that much extra work to remove the Lower Intake Manifold, and you might be surprised how much carbon builds up on the 5/6 port actuator channels, their arms, and the sleeves, themselves. I was impressed that they actually rotated under the 4-6psi from exhaust backpressure and after cleaning, they were much easier to operate. Note that there are small rubber O-ring seals which keep the actuator rods from becoming vacuum leaks over time. These are easy to lose when you pull out the actuator rods.

Basic cleaning principles apply. Use lots of fluoridated carbon and brake cleaning products and removal of the LIM ensures you're not spraying all the carbon into your engine. That's bad news if chunks of carbon end up in your seals or Oil Control Rings, especially. Scraping carbon off of the sleeves and polishing with brass bristle brushes worked well for me. You should be able to rotate them smoothly by fingertip once reinstalled. If there's any binding at all, remove the LIM and find out what's causing it.