1.6 n/a throttle lever on pump sticking

[ldeikis]

Hey all. This car was my daily for 4 years, then sat about 18 months. After cleaning the mice out of the heating system, I'm driving it again. I'm having an issue where the throttle will sometimes not release when I lift off the pedal. This varies from annoying to dangerous.  The cable is totally free, it seems to just be gunked up where the lever and springs are on the top of the IP. I gave it some love with WD40, which helped some but didn't cure the problem. My intuition is that it is an external issue, not hanging from the pump misbehaving. Can anyone offer guidance on how/if I can remove those levers/springs to really clean them up?  The pump doesn't leak or have any air intrusion at all and I'd really love to NOT accidentally open it and enter a world of pain.

Thanks for any guidance...  I'm enjoying having the thing on the road again, but this is no good.

It's an 81 rabbit w the 5 speed (so no kickdown etc) for what it's worth.

Luke

[Gizmoman]

Just a WAG but possibly the mice found the accelerator cable cover tasty while they camped in your heating system? A simple check would be to disconnect it and see if you can push/pull it easily - maybe you already tried that though..

[ORCoaster]

BE Sure to make a mark across the throttle lever and the shaft before you pull the lever off.  This is the bane of most folks that pull that lever and get it off splines that it currently is on. 

I undo the 10mm nut with a nut driver and then scribe the line.  Then using a pair of needle nosed vice grips I get a bite on the springs and bring them off the keeper and over the top to release them.  You can do that first if you want so that the nut is still holding it in place.  Once you take the tension off the first spring the second isn't so hard to release.

I would get the gunk out between the shims and the arms one at a time.  Pull off the top piece, clean set way far away.  Then work down laying them all out in a row just like they came off.  Once you are completely stripped off then I would WD 40 the shaft as well and twist it back and forth to make sure it is free.  That might be the big problem after the sitting spell. Just dry and tight.

Let us know how it goes.  DAS

[ldeikis]

Thanks.

I carefully pulled it apart--it was pretty straightforward, one part was formed to only fit correctly or 180* out, the second had a hash mark already stamped to line up with a mark on the end of the splined shaft.

Cleaned it all up with kerosene and a bit of steel wool and put some moly grease on it and put it back together.  Problem solved.

One thing I can't figure out, though:  What's the purpose of the "bottom" spring and arm on the throttle assembly?  With the assembly put back together, there's still too much friction for that little arm to do its thing.  Even with the nut loose-ish, it has too much friction...  when the throttle is pulled, it allows movement, but when the throttle is released and the top lever goes back to idle position, that "bottom" arm only relaxes to about halfway, where it does nothing.  If I remove the nut and top assembly, then the spring and lower arm firmly spring back to their idle position, but with the top arm on, it doesn't.  The throttle acts normally driving, and there's just one shaft for the whole mechanism to be manipulating, so it's got me scratching my head. Is it just some kind of backup to ensure the pump goes to no throttle if the top spring breaks?

Slightly unrelated question:  I seem to have a very slight injector clatter noise at speed.  It's faint, but sounds like a quiet version of the mayhem you get during the first 20-30 seconds of a cold winter start.  This is a noisy beast with an exhaust leak complicating the issue, but I think that's the sound I'm picking up, and I think it's new, though I can't pinpoint it as new-since-cleaning-up-linkage vs new-since-getting-car-back-on-road.  There's nothing I could have done to cause that, right?  I owe a timing belt and re-timing pretty soon anyway, and will swap in new injectors if the noise doesn't go away.  Hoping to get to that within the next few thousand miles.

Luke

[vanbcguy]

That's working as designed...   

My understanding is that it is supposed to let the pedal feel softer till you are about half way on it, and then pressing the pedal further requires more force.  It is to 'encourage' you to stay in the lower accelerator pedal range which in turn will provide better economy.  Lots of gassers have a similar configuration - our 1.8T for instance, despite being drive by wire, has an extra spring for the last 1/4 or so of the accelerator pedal travel.

[EcoTX]

One thing I can't figure out, though:  What's the purpose of the "bottom" spring and arm on the throttle assembly? 

Is it just some kind of backup to ensure the pump goes to no throttle if the top spring breaks?

You got it.

No way in hell SAE would allow just one spring on such a mission critical component like the throttle on a diesel injection pump.
Always gotta have a backup in case of failure.

Mine only has one spring, hopefully it doesn't break or pop off one day and send me into "unintended acceleration" mode right into another car, tree, or out into an intersection.
I should probably put the other one back on. 

[RabbitJockey]

when i mine did this i just sprayed lithium grease all over it ;^P

[ldeikis]

Thanks for the feedback...

On to the next task.


Luke