Rev jumping on idle after High pressure pump rebuild

[modex007 4]

Hi,

 

I just rebuild high pressure pump with bosh seals kit. Because it was leaking and verry rough running engine, shaking etc.

Refited everything.

Flushed just running low pressure pump with 4l diesel, then just on few starter runs. And fited all back.

And now it's idling strangely.

 

What could i missed or done wrong?

Very strange.

https://youtu.be/YmQzZDPV5XI?si=kfDMu6bgkvsCIoXY

 

But it starts quiet fast now and not shaking as before. Maybe SAM needs to relearn? Or i just done something not good?

 

[Mjolinor 85]

fuel filter?

[modex007 4]

Changed recently

[Mjolinor 85]

I don't think I would worry about it as long as it goes OK.

 

You could try disabling the EGR. Presumably you have done the air filter too.

 

Is it the same hot or cold?

[modex007 4]

It started just now after high pressure filter orings change. Took a ride, after 300m engine shut off. Waited for minute, started again and slowly came back home. That idling seems gone away. Will wait for engine to cool down and then check again. Afraid to go further ride now 😃. Maybe some air in the lines after change. Dont understand. Its quiet simple job nothing to destroy 😒.

[Willys 741]

Hmmmm....?
There is plenty to upset if you don't take care when rebuilding the high pressure fuel pump, ask me how I learned this...lol
Hopefully to didn't try and sand or buff mating surfaces of the 3 heads of the pump? Or use a sharped edged scraper and gouged the mating surfaces?  I tried to surface match the heads to the body when i did mine the first time....
Also did you install all the "O"rings correctly? Where the mating surfaces of those clean and debris free..?? Did you mis-match the heads from one location to another? Or rotate them? 
The biggest issue I found with mine after rebuilding mine searching for similar problems was on the valve body which lives in the head, it has a coil spring and a round plate that seals or regulates the flow of fuel....look very closely at how this coil spring is sitting in it's captured clamp that looks a bit like a top hat. I finally noticed that one of my coil springs had wedged itself to one side and wasn't applying enough pressure to that plate it controls. Once I noticed this I replaces all 3 of these domino sized control valves and my pump ran perfectly again. But it took me 3 tries at rebuilding it to notice this problem. 

OR, if you can find a good running pump from another engine maybe you can swap it out to see if it is the pump that is causing your issues. Yes something I have done many times hunting for the problem. 

As for those valves you can buy them easily off the internet....and aren't stupidly expensive.

[modex007 4]

Nono was too afraid to polish those heads, and they didnt look bad at all. But now i'm worried if when installing i didnt rotate to the correct place of those. I didnt scrape anything, just cleaned with some cleaner and rug very carefully. Also each piston removed and put back to the same place. Now i started again car and it runs good without any revs ups and downs.  Didn't test drive it.

 

I think will need to dissasembly again and check if i installed in correct prepunched possition these pistons...

 

Hate all these hard reaching screws 😂

 

[modex007 4]

Checked pump again, put piston into prepunched locations. starts quick and easy. left outside for colder temperature, started quickly. 

will test drive later. but looks promissing. Now need to fix a squeky belt. cold brings issues, what can i say