How long should I have to crank after injector replacement (OM616)? - Page 7 - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #91 07-17-2012, 11:54 PM

Quick question/observation: After sitting, all the fuel runs out of the line between the lift pump and secondary filter. It will rise again when I pump the primer, but after sitting for a couple hours, it's empty. I'm assuming all the fuel ran A) back into the lift pump or B) out the fitting on the going end of the lift pump. If it's A, would that be a failure of the valve in the lift pump? Fuel is not supposed to fall back into the lift pump, is it? I will do more cleaning to investigate the possibility of B first.
Also another question on bleeding via the pressure valve. Should I be cracking the larger bolt (17mm) or the smaller bolt on the outside of it (15mm I think)? I've been cracking the 17mm one and it does bleed out of it, but wanted to make sure I had it right.
I did also notice tipping the bottle to the side (thus reducing the amount the fuel needs to go up out of the bottle seemed to reduce the amount of air getting sucked in. Might have just been a coincidence but I'm considering trying to change the bottle setup (or just clean the tank strainer, tank vent and tank, which I'd have to do anyway even if I get it to start).

funola · #92 07-18-2012, 12:04 AM

Keep the bottle till you have the air issue fixed. Put more fuel in it, keep it 3/4 full so both lines are submerged.

Loosen the 17 mm pressure valve banjo bolt just enough to let air out as you pump away. Once you get fuel coming out of that banjo bolt, tighten it and keep pumping till you get solid fuel into the clear return line, then crack one injector nut slightly and the engine should start. Feather the throttle to keep it running and get all the air out of the system. You should see foamy fuel in the clear line till all the air is out and the fuel should not drain down after you shut it down. If it does, you still have leak(s) which must be fixed.

layback40 · #93 07-18-2012, 11:24 AM

Quote:

Originally Posted by BodhiBenz1987

Quick question/observation: After sitting, all the fuel runs out of the line between the lift pump and secondary filter. It will rise again when I pump the primer, but after sitting for a couple hours, it's empty. I'm assuming all the fuel ran A) back into the lift pump or B) out the fitting on the going end of the lift pump. If it's A, would that be a failure of the valve in the lift pump? Fuel is not supposed to fall back into the lift pump, is it? I will do more cleaning to investigate the possibility of B first.
Also another question on bleeding via the pressure valve. Should I be cracking the larger bolt (17mm) or the smaller bolt on the outside of it (15mm I think)? I've been cracking the 17mm one and it does bleed out of it, but wanted to make sure I had it right.
I did also notice tipping the bottle to the side (thus reducing the amount the fuel needs to go up out of the bottle seemed to reduce the amount of air getting sucked in. Might have just been a coincidence but I'm considering trying to change the bottle setup (or just clean the tank strainer, tank vent and tank, which I'd have to do anyway even if I get it to start).

Now you are getting to the bottom of things !!
Air leak on secondary filter.
It should not be causing air into the system once it runs though.
Running back does suggest the valves ( there are 2), in the lift pump may be weak but this should not stop it from running, if both the supply & return lines are under the fuel level.
You may wish to try that lift pump you were offered, or better still a rebuild of your lift pump. New valves may help, they should be cheap. Dont know what a kit would cost.
The seals on the secondary filter need investigation. The injector return lines should also be checked.
The inlet fitting to the secondary filter may have a leak.
I am just throwing out suggestions.
Good Luck !!

funola · #94 07-18-2012, 12:17 PM

Check the smell of the engine oil and level on the dipstick. If the level is high and smells like diesel, the lift pump is leaking fuel into the crankcase.

Did you try the white tissue trick? Make sure all joints are dry first (per white tissue, then prime the system, try to start it, then go around with the white tissue again (every joint should be dry except the one you loosened while priming).

BodhiBenz1987 · #95 07-23-2012, 12:25 AM

All the joints stay dry, though I checked with a paper towl (the blue ones) rather than tissue paper. It is pretty easy to see any moisture on those towels. But I can still see the air, despite following the procedure above, so it has to be leaking somewhere. I did add to the diesel jar and make sure both lines are submerged. I'm still thinking it doesn't help to have such a steep climb for the supply line out of the bottle but maybe I'm not understanding the physics of it.
I bought the lift pump rebuild kit since it was less than $5 plus bought replacement seal rings for all the banjo bolts. I also bought the little seal rings for the secondary filter bolt. Will try replacing those things, though I have not been very motivated lately.

Edit to add: Engine oil level and smell are normal.

funola · #96 07-23-2012, 11:25 AM

Quote:

Originally Posted by BodhiBenz1987

All the joints stay dry, though I checked with a paper towl (the blue ones) rather than tissue paper. It is pretty easy to see any moisture on those towels. But I can still see the air, despite following the procedure above, so it has to be leaking somewhere. I did add to the diesel jar and make sure both lines are submerged. I'm still thinking it doesn't help to have such a steep climb for the supply line out of the bottle but maybe I'm not understanding the physics of it.
I bought the lift pump rebuild kit since it was less than $5 plus bought replacement seal rings for all the banjo bolts. I also bought the little seal rings for the secondary filter bolt. Will try replacing those things, though I have not been very motivated lately.

Edit to add: Engine oil level and smell are normal.

Don't worry about the steep climb.

When you suck on a straw drinking a soda, isn't that's a steep climb? The lift pump can suck 100 times more powerfully than you are capable of.

One thing I'd suggest doing is check with the dealer by the p/n stamping on the secondary filter housing that you have all the correct seals installed. I understand there are different version sec filter housings out there, some have more seals than others. I think the air leak is in the secondary filter somewhere since it is at the highest point and you say that fuel is draining down the clear (brown) line between it and the IP.

Potential leaks at the sec filter can be:

Missing seal.

Dirt between seals and gaskets. Inspect (with a magnifier) all seals and their mating surfaces. Or test with MityVac

Cracked banjos from over tightening banjo bolt. Inspect with a 100x magnifier. Or test with a MityVac.

Testing with a MityVac is easier said than done unless you can rig up the correct fittings.

I'd suggest changing one thing at a time and test so you will know what the culprit is.

BodhiBenz1987 · #97 07-30-2012, 12:05 PM

I now replaced (one at a time): the seal under the secondary filter bolt, and the rubber ring on that bolt, seals on the 3-way banjo fitting on top and the seals on either side of both banjo fittings on the secondary fitting. I also made sure the filter seal area was clean and all banjo connections were clean and inspected the fittings with a magnifier. No luck. It did start up without quite as much trouble after I replaced the filter seal, but alas, just filled with air again and left me back at ground zero.

After that I decided to take off the lift pump and inspect/replace the valves. I did notice some black stuff on the surface of the banjo bolts when I took them out, and there was black stuff in the primary filter (which is replaced now) so I think the whole thing was badly fouled with algae. Not seeing any of it in the fuel returns now that I've got clean diesel running through but maybe it's gunked up some internals.
I got the lift pump off, but wasn't quite expected the fountain of oil to come out?! Is that normal? I'm assuming this is just the oil in the IP, and will eventually stop pouring out? I just stuck the lift pump back on enough to get it to stop draining last night, and will address it today. Man did I make a mess. I'm a little confused about what I should be replacing once I got it off, after reading a few lift pump threads, but I guess once I take it apart I will have a better idea. I have the lift pump kit (valves and springs plus copper seals) and a gasket that goes between the pump and IP housing.
Also, should I try removing/inspecting the pressure relief valve while I'm making this big mess? It's the only other thing I can think of.

cullennewsom · #98 07-30-2012, 12:55 PM

Quote:

Originally Posted by BodhiBenz1987

...I think the whole thing was badly fouled with algae.

Diesel tanks and systems can have microbes such as Bacteria, Yeast, and Fungi, but there is no Algae.

funola · #99 07-30-2012, 04:02 PM

Wow, your 240D is a stubborn SOB ha? Rebuild the lift pump first since you have the kit. Oil is IP lube and will stop draining, should not be more than 1/2 pint.

BodhiBenz1987 · #**100** 07-30-2012, 06:19 PM

Quote:

Originally Posted by funola

Wow, your 240D is a stubborn SOB ha? Rebuild the lift pump first since you have the kit. Oil is IP lube and will stop draining, should not be more than 1/2 pint.

Yes, it's being a bit of a brat. Maybe it's rebelling because I left it in the back of the garage too long while the other cars had all the fun. I'll let the rest of the oil drain out ... I figured it couldn't be too much since most of the oil would have run down into the oil pan by now! When I put it back together, I take it I can just add some oil to the crankcase and the pump will just suck more oil back in when I crank, or does it need to be pre-oiled somehow?

BodhiBenz1987 · #**101** 08-04-2012, 08:53 PM

Well ... I took apart my lift pump and after much confusion figured out it was missing the suction valve, which was supposed to be under the primer pump.

The good news is, with the valve replaced, it primed really fast ... the difference in fuel flow is huge when pumping the primer pump. The bad news is, air is still coming in. It still started and ran with the throttle down, but then I saw bunches of air come through the return line. The air just kept coming and coming ... it did manage to idle on its own for a while when I let off the throttle, but then cut out. The fuel flow looked much faster and steadier through that return line than before, but it still had the air in it. It seemed to go in waves ... like a big bubble followed by a bunch of little bubbles, some good fuel, then another big bubble, etc.
I did hook a Mitivac up to the lift pump while it was out and it held vaccuum, on the intake side, after I cleaned it, put the right valves in, put in new seals and then the fittings. I was so optimistic when I discovered the missing valve and how better the fuel flowed with it in.

funola · #**102** 08-05-2012, 10:33 AM

Do you have a clear line between lift pump and secondary filter? If you don't have bubbles there, air is getting in after it.

louis4052 · #**103** 08-05-2012, 11:33 AM

Quote:

Originally Posted by BodhiBenz1987

I did notice some black stuff on the surface of the banjo bolts when I took them out, and there was black stuff in the primary filter (which is replaced now) so I think the whole thing was badly fouled with algae. .

Black goo in the primary could be old fuel lines breaking down. If the fuel lines are old I would replace them just to be sure.

BodhiBenz1987 · #**104** 08-06-2012, 10:25 PM

Louis, I did replace all the lines but it's possible some of the residual black stuff was from that. Funola, I do have a clear line but it's very hard to see through due to browning. I can see some bubbles in there but it doesn't look like anywhere near as much as is coming out of the return line on the back of the IP.
I did take out the pressure valve, stretch the spring in it and replace the seal ring, just for good measure. Primed, started, and it seemed to make things worse. Fired but sounds like on 3 cylinders and I got a funny smell (which might have been the starter ... couldn't track down it's source).
Only going to try two more things: replace hand primer (probably a waste of money but it is kind of noisy and I really want to rule it out) and swap in extra primary filter I have lying around, just in case the one that's in there is a dud and causing an obstruction. The next thing I think would be find a good used IP, but I'm not sure I want to get into that.

funola · #**105** 08-07-2012, 08:55 AM

Before replacing the primer pump, replace the clear line between the lift pump and secondary filter so you can see if there are bubbles there.

a quick way to do that before getting one from the dealer is go to home depot and get a 1 foot section of 5 sixteenths and 1 quarter inch clear vinyl tubing. cut the old line off at the barbs and use the size that would fit the tightest over the cut barbs. submerge the ends in boiling water to soften it so it can be stretched tight over it. if it's tight you don't need hose clamps while testing.

why are you replacing the IP? what makes you think it's bad?