Diesel Throttle Sticking

[ProjectPurity]

Hey, i've had an 81 rabbit for a while now, and it's always had a problem where the throttle will not drop the whole way when switching gears or putting it in neutral. The problem has worsened over time. to the point where i can be at regular idle, put the gas in a little and it will not drop AT ALL whereas it used to eventually return.

I've entertained the idea of it being one of the springs on the IP. I've entertained the idea that it's "running away" but since i'm venting the crankcase and the valve cover, i don't think it's due to blowby. The injectors have been removed recently, cleaned, and reinstalled after re-setting the heat shields. I'm not sure if they are problematic or not, haven't really thought about them that much.

Oh, one more thing, if it's stuck at 1/4 throttle (for the sake of things i'm saying 1/8 is idle), i can knock it back to 1/8th throttle (idle) by sticking it in gear and letting out the clutch to bog it down a little.

What could this be?

Thanks,
JB

[stevethefolkie]

I'd suspect the throttle cable - this is a potentially dangerous situation (it could either snap at an inopportune moment leavning you with no throttle or it could stick at WOT) - pretty easy fix (remove the old cable, install a new one) - and (as I recall) pretty cheap as well.

[ProjectPurity]

it's certainly not the throttle cable. I have revved it up right at the pump by pulling the lever.... i've greased both the throttle return spring and whatever that other one is right on top of the IP.

Some success.... i ran some Lubro Moly Diesel Purge through, letting it soak overnight in the IP, and then a tank full of petro diesel with some Power Service in the white bottle. It stopped sticking all together.

then, i threw some of my biodiesel in. It started back up immediately. I'm thinking right now that i need to make sure that my fuel is of good quality.... something i was doubting about that batch.

edit: Ran straight diesel and some PS again.... problem solved once more... lets see how it likes the best (and most expensive) biodiesel i've ever made!

[Fourt1thirty]

Forwarding this to my diesel guy. He'll have the right answer for you.

[vwmike]

It's kind of sounding like you may have some issues with the internal linkage between the governor assembly and the control collar. That linkage peice on the top essentially pulls on a spring so it is the job of the internal linkage to return the control collar back to the idle position.

[ProjectPurity]

Thats great!


Although, it begs the question... what do i do about it? It's currently not giving trouble, but if the problem comes back, i would like to know what the best solution is. Like i said, running petrodiesel through with some Purge seemed to work, but if this is a sign of something that will eventually need some real attention, i'd like to know.

Thanks all.

JB