om605 runaway help

[zoob98]

Hello to everyone im new here. a bit of background on myself im from Perth Australia a panel beater by trade have owned auto wrecking yard in the past have rebuilt diesel and petrol engines in the past plus numerous head gaskets all types of car repairs
My wife and i were given a Mercedes Benz 1998 c250td Elegance with 138000km on the clock was originally owned by wifes fathers(Dec) her brother has had it for year and it came to us with diesel pump in boot plus two other diesel pumps in a million pieces and i was told the complete one was in good working order the timing mark was on 14 degrees atdc so all good so far i used the pump locking tool and fitted pump before i put vacuum pump on i rotated engine manually and all seemed good pump timing came back with blade in centre of hole in pump finished putting everything back together and bled diesel system and attempted to start after a while it fired up but ran rough and had loud knocking so i turned off so i moved the pump and started again still loud knocking then all of a sudden it went to full acceleration i turned engine off but still kept going i had heard of runaway so i quickly looked for somthing to cut air off but it stopped was at full throttle for about 6 seconds so i looked around fiddled with a few things and removed intercooler pipe and like an idiot i started again loud knock before idle rough then full throttle so grabbed a rag put over cooler inlet rag disappeared so now panic is setting in grabbed big pile of rags held over cooler inlet and it stopped. It was the most frightening experience with a car in my life was at full throttle for about 10-15 seconds.So i rang to get more info on why it was pulled apart it turns out mother in law drove it from perth to kattanning about 350km no problems then she fueled up and after that broke down so me thinks she put petrol in so i have put little pump on main inlet fuel line and filled two jerry cans sorry for long story but more info the easy it will be to get help this car is Immaculate
my first question is ive emptied tank but it still says quarter of tank and ive heard this is common on these models so how do i get rest of fuel out
when this engine runaway where was it getting a fuel source
when these clowns were messing with pump could they have moved the timing blade inside of pump and put timing out
even after all this i could still see bubbles in fuel lines
the original pump is all black inside
what do i do about the rag that got sucked in somewhere absolutely no trace of
any help with any or all would be so welcome i think im in a bit of a pickle Cheers

 

[grober]

Too many unknowns to suggest anything. Unlike the earlier OM605 mechanically controlled pumps the W202 turbo OM605 will be electronically controlled with an alda device for control off boost. Sounds as if the timing is OK but the control is off/ faulty?
OM605.960 manual pump conversion?
and these guys videos may be usefull/
DieselPumpUK

 

[zoob98]

thank you for the response grober i will get to the bottom of this and will post what i can find out still got to clean fuel system out start from there is guess is the best place is there any chance oil going to turbo could've got inside inlet

 

[grober]

This is a particularly good video of fitting older [tuned] mechanical pump on a OM606 to replace an electronically controlled one. 6 cylinder instead of 5 but will give other folks reading this thread a better idea of what's involved. LOTS OF TRAPS FOR THE UNWARY! In terms of runaway it might be turbo related as you say.
Diesel Engine Runaway – What is it? What do you do about it?

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[Joderest]

I have seen two vehicles do this, and is very frightening. One was a van on the motorway, funny enough, just out of services, it revved until something broke.
The other was a TD5 defender, known fault is that the injectors leak fuel into the engine, engine slowly fills up until the pistons pick it up and then it just runs. no way to stop it unless you can get it into gear and stall it.
Good luck with this

 

[zoob98]

Ok well i found where i went wrong in a big way .Because i never pulled this car apart and don't have a manual I'm guesstermating a bit ,i didn't see all the injector return hoses that loop from pot to pot so not knowing them and not doing due diligence on the which way all the diesel flows through all the hoses i couldn't figure out where the small hose which is on the return line side goes until i picked up the inlet manifold and seen the plug for a small hose and plugged it in there not knowing that a vacuum sensor on the fire wall has a small hose as well so pretty much i was feeding inlet manifold with the injector return line a stupid mistake and embarrassing but i said i would let you know. it would explain the rough running when first started up and the runaway effect that i never want to go through again now i know whats wrong i will put back together and let you know how i go

 

[zoob98]

sorted the runaway and timing issues but was still not running as good as a motor with only 138000km on it keep seeing air in lines so replacing all O rings noticed bubbles around one of the delivery valves so i grabbed one of the other pumps that came with this car in pieces and got one of the delivery valve splined locking ring and welded it to end of steel tube then sacrificed one of my half inch drive sockets and welded that to other end worked a treat in removing the valve and replacing it so tomorrow will bleed up again and see if that stops air but i suspect that this car has fuel tank issues with the saddle system and the venturi set up still cant work out the fuel gets to otherside when you begin on empty cant see venturi working when theres no fuel to start with but the car runs out just under half on guage so theres got to be some issue and all posts about running out of fuel all leave out one crucial point how many litres to put in tank i could not get this to bleed up until i put two jerry cans in 40 litres after i drained it suspecting petrol contamination i put some of this diesel in two containers poured a little petrol in one then placed a foam cup in each container for afew hours when i came back the one i put petrol with diesel melted the other stayed perfect so no contamination another reason to suspect tank issues so if you run out of diesel 20 bucks in a can isnt going to get you going unless maybe the fuel system is working perfect i can the injectors coming out aswell but lets deal with the air first cheers

 

[Bellow]

was at full throttle for about 6 seconds so i looked around fiddled with a few things and removed intercooler pipe and like an idiot i started again loud knock before idle rough then full throttle so grabbed a rag put over cooler inlet rag disappeared so now panic is setting in grabbed big pile of rags held over cooler inlet and it stopped. It was the most frightening experience with a car in my life was at full throttle for about 10-15 seconds.s

CO2 fire extinguisher (directed into air inlet) is your friend.

 

[zoob98]

air in fuel i keep getting air in fuel and have replaced any leaking hoses and O rings but still it persists so now im thinking fuel tank system the guage never goes to empty unless ignition is switched off now with this saddle tank theres a venturi thats suppose to equell the the amount of fuel in tank to each side it runs of the returning fuel when not working properly from what i under stand the car only uses one side of tank is that correct and while not working properly is it possible for this non functioning venturi to suck back air from empty part of tank back up system cheers

 

[zoob98]

so ok ive got the tank drained again to do this i rigged up a windscreen washer motor hooked it up to fuel feed line pumped into jerry can had to suck on hose to get it going then placed on return line did the same so i could drain both sides of tank i now have both fuel senders out so i can clean venturi and check for any blockages the passengers side sender is the return side and is plugged into one hose that travels over to drivers side of tank there is another hose on sender and drivers side has same one aswell cant find anything on what its purpose is or what the two aluminium round pieces on outside of sender with allen key hole do also so im a bit stumped and cant find out if diesel tank has swirl pot and strainer to be honest there doesnt seem to be a fuel system explanation in manuals or any where else i here about venturi but no explanation i understand that the return goes through venturi on passengers side sender picks up fuel and transfers it to drivers side which is fuel feed side but no explanation as to what happends then ie drivers side venturi why is it needed can i fix it clean it or check that its functioning i know people replace fuel tanks because of this but buying brand new fuel tank is out of question and second hand one could have same problem there is a lot on the saddle tank problems on various forums but looking at forums from 5 years ago right up till today no seems to have solved the problem which im positive is caused by low pressure return to tank but ya cant fix anything till you see a full explanation of fuel system including from filling to vent pipe to pressure pipe fuel senders venturi system fuel out fuel in to lift pump the heater the filter system high pressure pump injectors and return theres bits and pieces everywhere a few guesses some ideas but no full system explanation if i find it or figure it out i will post it cheers