How long should I have to crank after injector replacement (OM616)?
 

... I finally got remanufactured injectors from the dealer today, and carefully installed them with new heat shields and new (used) hard lines on the 240d, which has been sitting for about a month. It won't start, and I've cranked quite a bit. Not only will it not start, but when I crack the line at the injector, no fuel leaks out. Fuel didn't even leak out when I cracked the line at the injection pump. I did prime the IP, and bubbles are not coming out of the nut on the filter, just diesel. I had been tinkering with the stop lever when I was experimenting with compression tests, so maybe I bent it? Or does it really just take a ton of cranking before fuel gets into the empty lines? I don't want to abuse the starter.

was the fuel line off at the IP?

the pump should be full of fuel still, you should only need to crack the lines at the injectors (all of them) and crank until fuel bubbles out the #4, then #3, then #2, then #1.

I did not take a line off the pump, so it should be full. I did not have the injectors cracked while cranked, maybe that's what I was doing wrong.

Take your time and give it a break regularly and the starter should be fine. I typically get fuel from the nozzles at the injection pump then hook the hard lines up at the injector. Crank some more till fuel comes out at the fuel injectors. Once fuel starts coming out there you can hook em up as fuel comes out. After two or three cylinders a healthy engine will start so be ready for it.

I've seen it take two batteries to get em going sometimes.

That trapped the Air in the Fuel Injection Hard Lines. Once trapped the Air compresses a lot and moves only a little bit.

Loosening the Hard Line Nuts at the Injectors allows the Air to escape fast and at the same time you can see if you are getting Fuel to the Injectors.

A long with that an old Fuel Supply/Lift Pump might have worn Valves or an Air Leak in the Hand Primer that could allow Fuel to migrate back to the Fuel Tank. It would take a bunch of use of the Hand Primer to bring it back up to the Fuel Injection Pump.

Thank you guys. After cracking the lines at the IP I got fuel there and buttoned them up, then got fuel at the loosened lines at the injectors. Still no start though. There is still a little bubble or two coming out when the lines are cracked, so maybe it still has too much air. Either that or the battery needs a new charge.

Did you change the spin-on filter? If you did, did you fill it with fuel before replacing it? filling it will help with that much less air to purge out with the hand primer.

You are either having air enter via the hand pump, or another source, or you haven`t full purged all the air out of the system.

If all you did was replace the injectors, then the only air will be in the hard lines to the injectors.

If you battery is depleated and not turning the starter fast enough, this can also be a problem.

Since you have a w124 and it is self bleeding, the 616 & 617 engines are not like that.

Charlie

My primer pump is the updated kind, installed a couple years ago, and it seems to work OK (doesn't leak all over like the old one). I did only change the injectors and lines on this round so I don't think there should be a problem with air in the pump (though I primed it a little anyway just for good measure). I will give the battery a charge with my dad's charger and try cranking more with the lines cracked. :)

If it was running ok prior to the work?

Fill the main filter before putting it up in position. Put the prefilter in place and pump the primer until you hear a swishing noise at the top of the main filter.

With EVERYTHING ELSE TIGHT, crack all lines at the injectors and have an assistant crank the engine. As soon as you see fuel dribbling from an injector line signal the assistant to stop cranking and tighten the line where you saw the fuel. Crank some more until you see another injector or two dribbling, stop cranking and tighten those. Continue until you have seen fuel dribble from them all and they are all tight. It will almost surely start at this point.

I once had a similar problem with a OM616. Are all the rubber lines crack-free? A hairline crack let air in periodically. I just happened to hear the hiss when a second person cranked while I observed. Changing that line made the difference after I purged all the bubbles. That car has been running flawlessly for four years since that fix.

Lesson: the rubber may look good, but still be cracked.

Did you crack the lines at the secondary filter too? I'd start at the line to the 2nd filter, then the return line, then at the injector pump then each injector. (if needed) I couldn't get my car primed after it sat a year, cracked the line to the 2nd filter and fired right up. But don't crank too hard and get your starter hot, and keep up with the battery charger as you already figured out. It was a pita.

Spray a little wd40 into the intake while someone cranks the engine. It should fire up on it and more than duplicates the required cranking to get the normal fuel up.

Too hot to do much today but tried bleeding more ... there is a lot of fuel coming out at each injector but still no start. It sounds like it's not cranking fast enough, though when I put the charger on the battery it's saying it's almost fully charged ... I'll leave it on for a few hours anyway. Would it be OK to use a booster pack to see if it just needs more cranking juice?
I don't think I have air anymore but I could be wrong ... I get bubble-free fuel out of the secondary filter bolt and lines at the IP. The car was starting and running OK prior to the work ... it has probably been 2 months since I last started it and it started easily then. The only problem was the engine was rocking at idle sometimes. But it started pretty easy even when it was cold out.
strelnik, do you mean the return lines? They are relatively new, but maybe I cracked one while pulling them off the old injectors. I could try replacing those.

X2


I would be spraying a lot!
Are your GP's good?
You can run a diesel with WD40 for a while ~ I have done it instead of cracking the injector hard lines. Works a treat.
When you pump the primer with everything done up, can you hear the fuel lifting the pressure control valve on the return banjo?
A hot day is the best time to try & start it!!

Good Luck !!

yep

It sounds like you are getting the fuel to the injectors. Is the glow system working? It should start once you get fuel coming getting to three or so injectors unless the engine is worn out.

I typically run at least one battery down when trying to get one going like this.

It might be loaded up with raw fuel from the multiple starting tries.

You really need a hot battery(as in fully charged) to get the beast to light off at this point. A booster pack would probably be safe to use on a good battery, one with a bad cell not so much. I know it's heavy, but you might think about getting the battery load tested at you local McParts store if it's more than a couple of years old.

When it does start, be prepared for a huge nuclear bomb sized mushroom cloud of smoke. :)

Battery charged overnight ... now it's cranking much faster, but still, no go. I still get a bubble or two out of the lines at the injector, along with a decent amount of fuel. Does that mean I've just got to keep cranking with the lines cracked? My dad's coming over so I guess we'll try the WD40.

It's not going to start with the 17mm injector lines cracked. Just wanted to make sure you were clear on that. Tighten them up and glow it a lot and should fire right up. Glow plugs working?

Oh yea, once you get fuel coming out at the injectors tighten them up.

I did tighten the injectors before trying to start, my description wasn't clear on that. :) First I cranked with them cracked, then when I saw fuel at all four I tightened them and cranked again. My dad came over and we tried it with the booster pak ... it seems to be cranking plenty fast, and sounds like it's maybe catching on one or two cylinders after about 6 or 7 seconds of cranking, but just won't do more than that. He was concerned about trying the WD40 and neither of us had time for me to talk him into it. He thinks it is a compression problem. I wouldn't be surprised if the car doesn't have great compression, but it started fine at 10 degrees last winter and started easily the last time I tried before parking it for this work. Which leads me to believe something has still got air in it ... or a combination of air and not the greatest compression, at least.
Would the fact that the fuel in the tank is fairly old have any effect? I could try adding Startron or new fuel, if it would make any difference.

Well the good news is it started ... but, it ran poorly for about two minutes then quit. Rocked at idle, light nailing from somewhere, then just shut off. Now won't start again. I saw some light fuel coming out of the nut on the spin-on filter, so I guess it was not tight all the way. I tried loosening it, priming (bubbles came out) and then tightening. Back to the same no-start situation. Now not getting fuel at all the injectors, so I'm doing all the priming over again.
I'm glad it ran but was hoping it would run much better with the new injectors, rather than worse.:(

Sure you put 115bar injectors in it, do they all match?

They all say 115bar. They are remans from the dealer, straight from Germany. Not that that makes them infallable. I guess I could take them out and get them pop-tested.

Have fuel at all lines again, nothing. I hate to say it but I'm about done with this car. Everything I do makes new problems rather than making it better.

Don't despair, I know these situations can make one want to pull their hair out. Take comfort in the fact the you are doing everything right. From reading your prior posts, you seem to be a very detail oriented enthusiast. I doubt this situation due to any error on your part.

IMHO, it's not you, it might be the injectors.

Since it ran with the old injectors, and the only thing that has been done since is to r&r the injectors with reman units, I would give some serious thought to trying the old injectors and see if it runs ok.

No sense in spending money on having the reman injectors pop tested if the problem is elsewhere(I doubt it).

See this link: http://www.peachparts.com/shopforum/diesel-discussion/26307-genuine-bosch-rebuilt-injectors-%96-poor-quality.html

I'm curious if the dealer would take these back as a defect based on your word? Or would they need some sort of proof?

It's not fair for you to have to spend money to have the new injectors pop tested. It's money wasted, because all the dealer can do is refund the injectors.

They should give you a full refund, if the car runs on the old injectors.

I suspect they are flooding the engine with fuel, and who knows how long they have sat on the shelf and corroded inside.

Good luck, and act fast on the possible defect return because some dealers won't do anything for you after a couple of weeks.

This is classic air in the fuel system.
I just wish you didnt have a phobia about WD40. It would have started long ago on it.
The last thing you should do is try & get it to idle. When you next get it going keep it at about 1500 rpm until it warms up. Take it for a run, keep 1 foot on the throttle all the time though so it doesnt stall. It may take 10 minutes of running before it settles down. Dont despair !
So near yet so far ! ~ Good Luck !

If it ran for two minutes, any air in the fuel system would be long gone.

"it ran poorly for about two minutes then quit. Rocked at idle, light nailing from somewhere, then just shut off. Now won't start again. I saw some light fuel coming out of the nut on the spin-on filter, so I guess it was not tight all the way."

My experience ( see sig below) has been that sometimes it can take a long while for air to be removed.
I can remember putting 1/2 a can of WD40 down the throat of my old 300D once after doing work on the injector system just to get it to run on its own. This was after pressure bleeding the fuel system.
There is probably air pockets in the injector hard lines at high points.
At idle the fuel flow is not great enough to push them out, it just dribbles past.
There may also be fuel quality problems as the car has sat for a while.
It is unlikely that the injectors are causing it to not continue to run.
It is clear there are still leaks in the system (see quote above), probably air leaks in as well as fuel leaks out.
Best get it to start again, keep the revs up, take it for a drive if you can & see what its like once it has warmed up.

Do you have the rack fully opened while cranking..............foot mashed to the floor?

If not, it will never start.

I have spent three decades around MB diesels, getting paid for it btw.

If it ran ok with the old injectors, and it won't run now then logic dictates that the new/reman parts are probably the problem.

It has only been sitting for 8 weeks, I doubt the fuel went bad during that time.

Then again, it's the internet and what do I know.....;)

I agree with Edward. It sounds like somebody missed the mark with the injector rebuild to me.

Heck, I have had engines in that were healthy enough to start up on one or two injector lines hooked up after I got fuel to them.

Time will tell.

If its her 240 that has over 300k miles on it, one could say its getting close to its use by date.
A tea spoon of oil down each injector hole before installing injectors is good for getting old motors to go after fuel system work. Helps the compression along.
She mentions plenty about air in the system, even after it has run.

If one injector was bad, I would agree, 4 is stretching it.
There would need to be a bad batch.
There has not been a flood of people with such problems.
The link to the thread about bad remanufac injectors is 11 years old !
On a Jap motor with those type of injectors we once connected all the injectors with them not installed & cranked the motor to make sure they were popping. Worked a treat.
Leaky or low pop pressure injectors dont prevent starting.

Over fueling is not a problem with a diesel, the extra fuel just puddles on top of the pistons. Its the atomized fuel that ignites.

BC made a valid comment ~ the usual idea of starting with your foot off does not work. ~ diesels dont flood like petrol motors.

yep

I find it quite unusual if all of them are bad too.

Next step will be to remove the injector, hook it up to the line and watch the spray pattern.

If it was running prior to the job and is getting fuel to the injectors then it should run. How did the wd40 test turn out?

I do not remember exactly all the changes you've done.

Did you remove the throttle linkages at some point? If so, it is possible to put them back incorrectly such that the fuel shutoff lever is always engaged (BTDT).

Did you change fuel filters? If so make sure there are no leaks.

Did you verify all glow plugs are good and getting voltage? It's possible one or more burned out on you since the last time it started.

It's always a good idea to change only one thing at a time.

At this point I would put the old injectors back. Sure, it will cost you 2 more sets of heat shields. It can get frustrating. On the positive side, think of all the practice and experience you're gaining.;)

Thanks for the input, guys. I have not done anything since my last post ... due to a non-car-related fiasco, to leave it short. I put the charger back on to start fresh and may try again tonight. If I can find a helper I'll have them squirt WD40.
Unfortunately I already turned the old injectors in to get the core charge back. It didn't even occur to me I'd want to swap them back, but I'm kicking myself now. That would be an easy way ... heat shields are cheap. At best I can call the dealer tomorrow in case they haven't shipped out my old injectors yet. I'm sure they would work out a way for me to take them back; they are very nice to me. But I handed them in Thursday so they are probably gone. :( I should have held on to them until the job was done ... lesson learned.
I was not pushing on the pedal ... I was not aware of the need to do that. If it starts with the pedal to the floor, should I just let up to about 1500 rpm after it catches?
Funola, the things I have done since I last started it are only injectors and hard fuel lines, as well as heat shields. I reused the return lines ... maybe I should replace them. After I took the old injectors out, I tried a compression test, which I had to bag because my tester fitting was defective. I did not do the fuel filters or other lines. I did try to prime via the primer pump yesterday, in case air had leaked in, to see if it would help. As I mentioned I must have left that bolt a little loose, because fuel came out the short while I got the car started. I thought maybe it sucked in air, but I'm still getting fuel at the injectors, and no bubbles from the filter. The GPs are the updated pencil types and are two years old ... I did check to make sure there is voltage at each, but have not yet removed each one to watch it glow. As far as the linkage goes, as I mentioned it's crossed my mind I could have bent it while trying to prop it up for the compression test. I only removed one linkage end to access the third injector to torque it, but put it right back where it came off ... not really another place to put it. If the linkage is bent, wouldn't holding down the throttle allow it to start, even if dropping back to idle makes it cut back out? That could tell me something.
Sorry if I missed a question or did not address something. I'm pretty sleep-deprived right now, which I am about to rectify.

Usually I floor it when bleeding it out. Then when it finally shoots to 5000 I try to do 1500 for several seconds.

High rev is necessary to push out the air in fuel. Flooring it is a figure of speech for high rev but don't do it. Flooring a cold engine will destroy it.

Get a length of 5/16 clear vinyl tubing from Home Depot and temporarily replace the cigar hose. The hose clamps will not fit so use rubber bands and wrap a bunch of turns around it.

Once you get it started, feather the throttle so it does not stall til it will idle on it's own, then intermittently rev the throttle till the bubbles clear and you see a solid stream of fuel, which can take a few minutes, IF you have no leaks in the system. If you have leaks, it will never clear and will suck in more air and stall.

It is not possible to know if an injector is good or not without pop testing, even if brand spanking new. Ask the dealer if these are recent rebuilds or if they have been sitting on the shelf. How much did they cost?

This is your entire problem. The amount of fuel delivered at idle is miniscule and it would take all day to get the engine to actually run without any air.

You must open the rack fully and get enough fuel (with associated air) until it will run. Hold the pedal to the floor until it climbs to 1500 rpm and then keep it there for a full minute.

Problem solved and new injectors are perfectly fine.

there you go

I am fairly certain they are recent rebuilds. They were not in stock at the dealer ... they ordered them from Germany. They were supposed to come within a week, but after about 10 days still hadn't come, so the guys at the parts counter called them ... at that point they said they had not shipped yet because they were waiting for the cores to rebuild them (i.e., waiting for someone else's cores I guess). If I'd known it would take that long, I would have just had someone else rebuild mine, but that's all hindsight now. They were something around $75 each. I'm sure if one is defective they would take it back (they have always tried to make sure I get the right parts/parts that work), but I want to be sure it is not air first. I will try the clear tube in place of the cigar hose.
Sorry if I'm being a little dense, but I'm confused about what my right foot should be doing as I crank. Where should I have the throttle while I begin to crank? Should I have it down as I crank, or only start revving up the rpms after (if) it catches? I assume it would not be great for the engine to floor it before oil pressure rises, though I noticed the oil pressure rises as I crank.
I'm debating whether to do anything tonight or just wait until my dad is available as WD40 squirter and air bubble watcher ...

Just read this after I posted my last post. Think I'm clear on the pedal procedure now. Thanks.:)

Results:
I tried the pedal as described, and got nothing. Upon further inspection I noticed a large pocket of air in the line from the IP to the spin on filter, so I pumped and pumped. Bubbles kept coming up through that line but eventually stopped, save one small bubble at the top that does not seem to want to go away. After that I cranked a bit with injector lines cracked, again, until I started getting fuel. Once I had two injectors getting fuel and tightened, it sounded like it wanted to start, which I guess is a positive sign. Once I got fuel at all four (took a long time to get fuel at #1 for some reason ...) I tried starting with the pedal down again and it started pretty easily ... I backed off and tried to keep it stable at what sounded like 1500 rpms. It was pretty erratic, as in would suddenly surge, then slow down as if about to die, I'd feather the peddle a little, it would surge again. I finally felt like I got it stable at about 1500 for a good minute so I started to back off ... it shut off immediately. I tried twice again (with breaks in between) and getting the same thing. Only now it reaches a point where it dies even with the pedal down. A couple times it almost died, then VROOOOOM, then back to dying. I know I don't have the greatest motor skills in the world (no pun intended) but I'm being pretty steady on the pedal, and sometimes it just is not responding to the pedal at all (I can see the linkage moving cleanly so I don't think that's the issue).
This sounds like air is continually getting into the system, or something is blocking the fuel supply, to me. What do you guys think? Could this still be a symptom of a bum injector? I would think it would be more consistent if one or more injector were bad? I'm leaning toward trying to find a leak going into the IP somewhere. Or is there any point at trying what I've been doing a couple more times?
One more thing that might be relevant: When I was pumping the primer pump to get the air out of the line between the filter and IP, I heard an occasional "glug" coming from the back of the car (tank) ... I have not had that happen in the past. It also just felt like the primer pump was not working well. I had to pump it A LOT and the fuel barely moved up the line. I think I mentioned it, but it is the new-style primer pump, put in 3 years ago ... no visable leaks from it.
Two more things to add: I looked at my receipts and while I have driven it as recently as 6 weeks ago, this tank of fuel is over a year old. The primary filter looks clear but maybe there's a bunch of gunk in the strainer. Also, something I found odd ... I did not see any exhaust smoke at any point in this. The car never smoked a ton to begin with, but it seems after a long sit, with cylinders full of fuel, and me revving the engine, it should kick out something?

Have you tried putting the old hard lines back on? Not that it would really do much, but you never know. One more thing to eliminate.

Also have you cleaned your tank recently? If it's been sitting for a while you might have a clogged screen back there. Switch the supply and return lines and try that.

It was not running up to the day or so before you changed the injectors?

lets start over.

what were the symptoms before you changed the injectors?

how long has it been since the fuel filters were changed?

#1 FAILURE is common to the 240, and it's due to the fuel lift pump weakening. you should search here for how to set and test fuel pressure.
the FIRST thing I'd do is get new filters, and fill them with Diesel purge or fresh diesel, then prime the filters with the primer pump, then try the bleed mess again.
I've had IMMENSE problems starting my SD when the clear primary filter was clogged up with buggs...

heck, I'd start with a "diesel purge" bottle of fuel connected to the lines of the tank in www.dieselgiant.com/injectorcleaning.htm style...

Yeah, set up a remote tank and try that. It sounds more like fuel starvation now than injector problems.

Take off the fuel filler cap when it's quiet and listen for a "swoosh". If you get a swoosh, the vent is blocked and that may contribute to difficulty getting fuel to the IP. Leave the cap off and see if you can get the engine to run normal, then clear the tank vent later.

Edit:
Your 240D is not driven regularly it seems. From day/ night temperature differential, moisture condenses at night when the tank cools off, this water accumulates and algae grows and clogs your strainer and tank vent. Try to get it running from a 1/2 gallon soda bottle of fuel. If you have no trouble doing that, you have more work to do to the tank.

My 85 I just bought sat in a garage not driven regularly and I have an algae problem also. The fuel filler cap was full of rust on the inside. Took apart and cleaned the black algae off the inside of the fuel sender today. I have Startron in the tank and it will slowly kill off the algae. I blew through the vent with compressed air a few times already but it is still clogged.

To sum up the turn of events: Roughly six weeks ago I attempted to do a compression test. The car started, ran and drove that day; I took it around the neighborhood to get it to operating temp for the test. It shook/rocked at idle with varying severity but never to the point it would cut out on me. It had been doing that for a while, hence the exploration. It also got occasional pinging at throttle, but again nothing that seemed to affect the engine's performance. For whatever it's worth, this car sat all winter while I chased down coolant leaks and learned my usual slow way about the cooling system. Once I finished that it started fine, and I drove it a little bit without any major problems (same iffy idle and occasional pinging), then decided to figure out why the idle was so choppy. As mentioned, when I went to do the compression test, my tester wouldn't work. But with the injectors out I noticed the nozzles looked pretty awful, so I decided to pursue replacing them. I for the life of me can't remember unhooking anything other than the injectors and hard lines, but maybe I jostled something old and brittle and cracked it? In short: Yes, it ran and stayed running the last time it had the old injectors in it, before any of the fuel lines had been disturbed.