OM603 Priming - PeachParts Mercedes-Benz Forum

treetops · #1 07-30-2015, 07:32 PM

I am expecting like new injectors back from greezer tomorrow, long story in itself, and I wanted to know the best way to prime them to get her going again.

First I am going to lift the rear on jack stands. I am, then, thinking of loosely fitting the hard lines to each injector and while a helper is cranking (20-30 sec intervals with 1 minute rest) to tighten each down when fuel comes flying out.

Is that about right, simple as that? Tips and experiences welcomed please.

Mxfrank · #2 07-30-2015, 07:47 PM

Half a dozen injector changes under my belt, and I've never done anything different than when installing new fuel filters.

jay_bob · #3 07-30-2015, 07:54 PM

You don't need to raise the rear.

If you didn't loosen the lines at the pump, you probably don't have very much air in the hard lines, maybe a little right at the end. Just like if you hold your finger over the end of a straw.

Now you will need to keep the nuts slightly loose at each injector to purge out that air bubble. Just be ready to tighten them promptly when the engine does catch.

BatteredBenz · #4 07-30-2015, 09:16 PM

To avoid almost all the usual problems especially with OM 60X engines ALWAYS start the car and bring the engine up to operating temperature before you do anything to open the under the hood fuel system. You will stand a much better chance of the engine starting and being able to run past the air that gets into the fuel spaces if you do, the easy start of a warm engine can make a great difference.

treetops · #5 07-30-2015, 09:24 PM

Quote:

Originally Posted by jay_bob

You don't need to raise the rear.

If you didn't loosen the lines at the pump, you probably don't have very much air in the hard lines, maybe a little right at the end. Just like if you hold your finger over the end of a straw.

Now you will need to keep the nuts slightly loose at each injector to purge out that air bubble. Just be ready to tighten them promptly when the engine does catch.

I did have to loosen the lines at the pump to move them outta the way to get to the injectors with my socket. I will tighten those first of course, but as I suspected maybe a little more to it than the same as a fuel filter change. Done that a handful of times and she started right up.

Quote:

Originally Posted by BatteredBenz

To avoid almost all the usual problems especially with OM 60X engines ALWAYS start the car and bring the engine up to operating temperature before you do anything to open the under the hood fuel system. You will stand a much better chance of the engine starting and being able to run past the air that gets into the fuel spaces if you do, the easy start of a warm engine can make a great difference.

Not sure how I am going to do that as the injectors have been out for some days. Do you mean to plug in the block heater or is your suggestion general in nature?

BatteredBenz · #6 07-30-2015, 09:30 PM

Quote:

Originally Posted by treetops

I did have to loosen the lines at the pump to move them outta the way to get to the injectors with my socket. I will tighten those first of course, but as I suspected maybe a little more to it than the same as a fuel filter change. Done that a handful of times and she started right up.

Not sure how I am going to do that as the injectors have been out for some days. Do you mean to plug in the block heater or is your suggestion general in nature?

Ok! That won't work for you this time but if you do that in the future you'll help avoid problems.

I would definitely plug the block heater in, is can only help! Filling the secondary, leaving the lines cracked at the injector, having the battery well charged, and not overheating the starter are all good advice.

Mxfrank · #7 07-31-2015, 10:14 AM

Nothing more than you would do with a fuel filter change. I've been thinking about adding an auxiliary electric pump to make this easier. Maybe a self priming pump on the return would do it.

vstech · #8 07-31-2015, 11:14 AM

If the fuel system is tight, hook up the lines, loosely at the injectors, disconnect the glow plug harness, crank the motor until the fuel dribbles out to injector #4, then stop and tighten 6,5,4 and allow starter to rest a a few minutes. Hook up the glow harness, glow the motor and crank. It'll likely start so be ready to tighten up the front three.

vstech · #9 07-31-2015, 11:17 AM

However... If you are having dv issues, and the ip is drained down... it will take a lot longer to do it.

Perhaps pinch the return hose then hook a leaf lower to the fuel filler neck and fill the fuel filter before trying to bleed the hard lines... A shop vac on blow works too.

treetops · #10 07-31-2015, 01:23 PM

Nice, thank you vstech. I dont think I have DV issues or may have caused them by loosening the hardlines at the IP. And thanks for the rest of the insight gents, we shall see Sunday morning with any luck.

GregMN · #11 07-31-2015, 01:49 PM

Change the injectors one at a time. Start the engine between each injector replacement.

You should have zero problems if you do this.

If, for some reason, you have removed the intake manifold to do this, you do not need to replace it to start and run the engine.

Never mind. You have all of your injectors already out. I replaced my injectors with a different set of rebuilt ones.

I use a low pressure, free flow, electric fuel pump to help prime the system anytime it is opened. Cost about $35. I only turn it on to prime after a service.

Phillytwotank · #12 07-31-2015, 02:21 PM

You can also use a vacuum extractor set up to suck fuel through the system. I use the same one that I have used for motor oil extraction. Pull the rubber return hose from the return side hard line and fit the suction there. This method has worked well for me in the past to get everything primed up before cranking.

Hit Man X · #13 07-31-2015, 03:06 PM

Why not prefill the spin on filter with some fresh fuel to help prime it faster? It is what I have done in the past. Along with foot to the floor.

Since the car has been apart, plug it in for a few hours to help raise internal temperature to help it fire off.

Agreed with what the other member stated about disconnecting the glow system.

treetops · #14 07-31-2015, 05:28 PM

Awesome input folks. So plug in block heater for a few hrs, top off fuel filter, use my topsider to suck fuel through the system to help prime, hook up all injector hard lines loosely, watch #4 for fuel when cranking,cinch down 6-4 stop/rest, then crank again and either hopefully she fires and then cinch down the rest. Pour whats in the topsider back into tank when done-theres about 2 qts of waste oil in there already...cant hurt right?

Drago · #15 07-31-2015, 05:59 PM

When I changed the injectors in mine all I did was have a full tank and filled the fuel filter with tranny fluid. Did I just get lucky?