How long should I have to crank after injector replacement (OM616)? - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #1 06-28-2012, 08:32 PM

... 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.

vstech · #2 06-28-2012, 08:37 PM

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.

BodhiBenz1987 · #3 06-28-2012, 08:42 PM

Quote:

Originally Posted by vstech

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.

engatwork · #4 06-28-2012, 08:45 PM

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.

Diesel911 · #5 06-28-2012, 09:17 PM

Quote:

Originally Posted by BodhiBenz1987

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.

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.

BodhiBenz1987 · #6 06-28-2012, 09:46 PM

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.

charmalu · #7 06-28-2012, 10:17 PM

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

BodhiBenz1987 · #8 06-28-2012, 11:26 PM

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.

engatwork · #9 06-29-2012, 07:12 AM

If it was running ok prior to the work?

Air&Road · #10 06-29-2012, 08:20 AM

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.

strelnik · #11 06-29-2012, 08:51 AM

Quote:

Originally Posted by BodhiBenz1987

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.

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.

Gscott · #12 06-29-2012, 09:06 AM

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.

barry123400 · #13 06-29-2012, 09:31 AM

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.

BodhiBenz1987 · #14 06-29-2012, 07:05 PM

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.

layback40 · #15 06-29-2012, 08:18 PM

Quote:

Originally Posted by barry123400

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.

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 !!