Out of curiosity, what exactly is one supposed to see in the lines? I pictured a steady stream of fuel, but there doesn't seem to be much of anything, really. Under what condition does a lot of fuel get returned from the injectors?

Anyway, clear lines are interesting to look at, that's for sure.

-Rog

With my car, I see a little bit of what I would call an air bubble at the top of the hose, and fuel. That's pretty much it.

Don't think the "air bubble" is much of a concern. Car has run fine otherwise.

Sounds like what I'm seeing. I guess most of the extra fuel control takes place at the IP then. It would be interesting to see what difference a hot rodded pump makes.

-Rog

Initially the lines were filled with air and droplets of fuel dancing around inside with every injection cycle. After 100+ miles all the tygon lines are filled with fuel. I can't see any air bubbles inside.

I'm worried about the low temp rating (165f) of the tygon especially on the om606 where they're covered up so I picked up some viton hose just in case. I'm going to keep an eye on them. So far the injector Wells are dry.

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CENSORED due to not family friendly words

I'd keep an eye on them. I had these neon green/yellow return lines a few years ago and one blew off spilled fuel all over made a mess. Being low temp and soft in durometer, these so called Tygon lines gets softer with increase in temp and can't handle much pressure. Make sure the tank vent is working. My estimate is they can't handle anything more than a few psi's. Injector return lines should be hard to pull off the barbs once installed. Not these, they are so soft a slight yank pulls them off.

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