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U417 is jumping/hopping (springen/ hüpfen)

Verfasst: 24.10.2021, 21:48
von vucko
Hello to all.

I am new owner of old U417 (U900) that need some love to be again in perfect condition.

Here is the problem:
The gas throttle pedal was jammed (seized) and it moved very hard.
After I was clean and unblocked it, I have a problem that whole throttle linkage are moving very easy thus I can’t control precisely the engine revolution by my feet. The result is that truck is jumping (hopping).

Could it be because I have some free plays (free movement) between the links and link’s joints btw pedal and injection pump? Or....

Engine is OM352 (353.902)

Thank you very much for support and ideas...

Regards,
Predrag

Re: U417 is jumping/hopping (springen/ hüpfen)

Verfasst: 25.10.2021, 16:57
von ingos406er
Hello Predrag

One mistake can by the air in the diesel-filter or the air in the pump !
An other problem can be the mushrooms in the tank , check the tank for a black not definaded thing its soften !

Frendly regards Ingo

Re: U417 is jumping/hopping (springen/ hüpfen)

Verfasst: 25.10.2021, 21:29
von vucko
ingos406er hat geschrieben:Hello Predrag

One mistake can by the air in the diesel-filter or the air in the pump !
An other problem can be the mushrooms in the tank , check the tank for a black not definaded thing its soften !

Frendly regards Ingo
Hi Ingo and thanks for the suggestion.
It looks like problem is not with diesel supply system. Simply, if I control the throttle by hand leaver (handgas) engine runs smoothly. I suppose that my foot is not calm (jumping/hoping too) thus it influence injection pump.

Re: U417 is jumping/hopping (springen/ hüpfen)

Verfasst: 31.10.2021, 11:06
von e.arens
Hi,

maybe you should change the spring, pulling the throttle lever backwards. If this spring is too soft, you may create easily more movements of the Pedal, as the required foot-force is so low.
I had a similar effect on my former 403, a new, stronger and correctly fixed spring improved the situation.

Give it a try
Edgar