OM617 wont start after Injector Replacement - PeachParts Mercedes-Benz Forum

haromaster87 · #1 10-31-2012, 10:32 PM

Hey guys,

So I got some rebuilt injectors from a reputable member on this site, they looked brand new. I got them for my 1984 300D turbo diesel. I pulled the old injectors and did an MMO soak in the cylinders for a week.

Today, was the end of the week on that. I put a new clear filter on which I used the hand pump to fill up. I also replaced the canister filter, which I filled with diesel. It wasn't quite topped off, but it was close.

I then installed the new injectors with new heat shields. Once I had them all torqued to about 59 ft/lbs, I ran the new return lines. I just ran them based on the two nozzles that were closest together, is this correct or is there a designated way to hook that up?

After that I re-attached the fuel rails and left the #1 open. I had my friend crank it until I saw fuel come out of it. Then I hopped in the driver seat and tried to start it. It turned over for a couple sec, and it turned on, and kinda sputtered. I gave it some throttle to keep it alive, but it still stalled out after maybe 5-7 sec. I started it back up and got the same thing but for like 4-5sec, and then again for just a couple sec. I went through and cracked each injector and had my friend turn it over. I feel like I would see very little drips which I thought was the fuel coming through, but I'm not sure. I haven't bleed the fuel system on this in forever and cant remember how much should come out of each fuel rail.

After I did that, I made sure all of the vacuum lines were still hooked up and tried turning it over again. Strong turn over, but no start. I decided to let the starter cool and come talk to you guys.

Questions: When I first cranked it over before re-installing the injectors, all of the cylinders smoked from what I assume was the glow plugs burning off the excess MMO, could this have ruined any glow plugs?

Do the return lines between injectors indeed hook up just based on which of the nozzles are closest together?

About how much fuel should come out of the line when bleeding the lines? Like a notable amount, or just a drip every few turns?

Could the MMO soak have ruined anything? I used less then half a quart. about 1/4 cup poured into each cylinder via funnel, and made sure to get the excess out before re-installing the injectors.

What else should I check?

Thanks guys!

-Tony

haromaster87 · #2 10-31-2012, 10:35 PM

Also, I should note that for the brief time it was running, I was putting the throttle to the floor just to keep it idling.

Diesel911 · #3 10-31-2012, 11:09 PM

Did you Crank the Engine to blow out any excess MMO before you put the Injectors in?

Some say differently but in the long run you are better off leaving all of the Injection Line Nuts at the Injectors loose until Fuel comes out of all of them; cranking and then tightening them up.

Did the Injector Heat Shields go back in properly. And, did you take a Flashlight and look down inside to make sure they did not flip over when dropped down into the Hole?

As long as the #5 Injector has one of the little return Nipples Plugged it does not matter how you connect the Return Lines on the Injectors.

I have done the MMO soak on My Volvo Diesel and My Mercedes and did not have the issues you are having.

pawoSD · #4 10-31-2012, 11:09 PM

Possible that you cooked the glow plugs, do they still dim the dome light when activated? Could also do an ohm test on them with a multimeter. It may just need some more cranking to get going.

When I have done the injectors (3 engines so far, all 617) I have not left any line loose, I just reattached everything and cranked, usually got it going within 20-30 seconds of cranking and another 20-40 seconds of sputter/rough running till it cleared up.

vstech · #5 10-31-2012, 11:14 PM

if you tightened the injectors in before removing all liquid MMO, you could have bent rods... you could have dead glow plugs, you may have air in all the lines...

haromaster87 · #6 10-31-2012, 11:28 PM

Doh, I forgot to put that down. Yes, before ever putting injectors back in, I had my friend crank over for a bit to make sure the excess MMO got pushed out of the cylinders. That is when the glow plugs put out the little bit of smoke. I will have to do the multimeter test as the light never worked before. I know the plugs would all light, just another issue with the light.

All of the heat shields went in correct and I made sure each one was the correct side up before installing the injector.

Also, another update. I suspected the lines needed to be bleed some more. I went and opened #1 all the way so I was looking at the end of the fuel rail. I had my friend crank for about 9sec, stop, and then another 9 sec. Never saw a drop of fuel come out.

This leads me to believe I have major air in the lines. However, I feel like after 18 sec of cranking, I should've at least gotten something.

The battery was sounding tired, so tomorrow my friend is going to come with the battery charger. I suppose then I will try opening all lines and cranking till they all spit fuel. I feel better knowing it may be a lack of fuel, but I'm a bit worried with how no fuel came out of the #1 line. I suppose we'll see.

pawoSD · #7 10-31-2012, 11:36 PM

18 seconds is not that long for empty injector lines, especially if there was some air in the spin on filter. Might take a solid 60-90 seconds to get it going. Try pumping the manual primer pump a bit first too.

If the glow plugs were heated to full temp then the MMO was blasted out with some cranking, it may have toasted some or all of them when the fuel cooked on the super heated tip.

mikeyfev1 · #8 10-31-2012, 11:40 PM

Actually, even though 9 seconds seems like a long time, its not necessarily long enough.

When I first got my 300D the fuel gauge didn't work and I ran the car completely out of diesel. I didn't know about priming correctly and nearly killed the battery getting it primed the hard way (with the starter).

As other have said, crack the hard lines at the injectors and don't stop pumping the primer until fuel comes out. Actually, one time that I was priming my hand pump failed so you could have that problem too.

Codifex Maximus · #9 11-01-2012, 04:28 AM

Get to pumping on that primer! I'd wear gloves if you've got the old style primer though.

greazzer · #10 11-01-2012, 09:31 AM

Howdy,

Did you try cracking each steel line a hair and then pumping? You should see the fuel to "bubble" thru the threads and seep. That way you know you're getting fuel to each injector. Also, you can hook up a slight vacuum on the last injector where you have the stubby return line and draw the fuel thru that way. You will need a source at the very beginning since you cannot suck it thru the IP. Sort of like bleeding brakes if that makes sense

haromaster87 · #11 11-01-2012, 02:04 PM

Thanks for the replies guys. After what you guys say, I'm confident it just needs to be bleed. I remember way back when I got this car, I forgot to put diesel in the canister filter. It did the same thing, ran okay for about 15 sec and just shut down and I had to bleed it then. It's been so long, I forgot how long it took me to bleed. But I do remember needing my buddies battery charger.

Also, I have the new style Bosch Pump so I know the pump isn't leaking. And I was always under the impression the pump wouldn't assist in bleeding the fuel rails. I thought it pumped fuel elsewhere.

haromaster87 · #12 11-01-2012, 02:11 PM

Oh I see, the hand pump fills the low pressure area of the IP, to get fuel in there, which I can then turn the engine over and bleed the lines. So I pump until I hear that squishing noise, then try turning it over, correct?

Stretch · #13 11-01-2012, 02:32 PM

You should be able to hear the fuel being pumped from the hand pump round the system and through the big secondary filter and back down the return fuel line towards the tank.

If you still have starting trouble then you might need to bleed at the injector connections (with help from the starter motor).

BoiseBenz · #14 11-01-2012, 02:34 PM

Tow/drag start is your friend.

haromaster87 · #15 11-02-2012, 12:44 AM

Welp, looks like it just needed a good bleeding. Got fuel dripping from all lines, connected em back up, and she fired right up. Ran a bit noisy at first, but I took her out and was immediately impressed. The off the line smoothness and power is unbelievable. She was puffin out some pretty good smoke at first, but after a few good runs, all that cleared up. Still has a nailing on one cylinder at idle before it warms up. Seems to be the same cylinder as before, but that doesn't worry me.

Also, after giving her a good drive, I checked my blow by. While not totally gone, it is much less, which made me quite happy.