So this weekend I pulled out my prechambers and replaced them with brand new clean ones. The lock collars on top have been leaking for quite some time after they were tightened in hopes of fixing it lol. In the process I noted that two of the injectors (4&5) were out of a 240d. Having spare housings and internals for 300sd injectors I cleaned and replaced everything but the lower cases as they were identical. However my car will not start acts like it almost will and when I tested the injectors out of the engine. I couldn't get the first one to pop. When I tried it on another line it popped just fine. Could my injection pump be bad...or is this a case of injectors needing balanced? Any thoughts on this greatly appreciated. Also to note it was starting fine in 22 degree weather three days before and fired right up the morning before but now it's so so close just never quite fires all the ways

To note since then i have pulled all the injectors out 2-5 pop just fine. I replaced the hard line in case it might be leaking tried different injectors still nothing...also the injector out of the #1 cylinder is working on other lines so it's good

The injection pumps are rarely the problem, but it does sound like yours is suspect.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Perhaps the problem is just in the #1 delivery valve. That one is removed to check IP timing via "drip method", so the guts could have be re-assembled wrong. It is a little hard to tell the correct orientation of the thick black disc. Perhaps it has been so for a while and just now started presenting an issue.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I just pulled the first two delivery valves cleaned swapped and replaced all o rings crush washers etc. I'm not sure what you mean by thick black disc? There is a piston looking disc type thing at the bottom with a groove cut in it around one side.....should the groove be facing down? That's how I reassembled them. Also there is a very small copper ring underneath those it looks like a crush washer but I couldn't easily get it out so I just cleaned and left in place. I had a thought about if those copper rings need replaced could I just put a small o-ring in the groove of that piston disc thing at the bottom? As far as I can tell there stationary once you tighten the delivery valve down. Letting the battery charge am about to give it a whirl again lol

After reattaching fuel injector lines I cranked on it till all the nuts around the top of injectors were leaking. Tightened them down proceded to crank on it again but no pop or fire of any kind. So hoping it's an air bleed situation I crank again while holding down the pedal this time it almost immediately pops and really acts like it wants to fire up. but my battery is drained again cause I really didn't let it charge for more than fifteen mins. Now I'll let it charge for an hour and then try it but damn it really feels better now...keeping our fingers crossed

So still haven't got it fired up but I have a question about the inner working so f the injection pump. I removed the first delivery valve on the IP and pumped fuel through to see if it was flowing smoothly...well it did beautifully but when I stop pumping fuel just drains back into the bottom of the IP no matter how long I pumped..

Is that normal

Ok so some conclusion last night. I finally got it to start on wd 40 after coating my air filter. I did try to spray directly into the intake while cranking but that didn't result in much it did get it to pop a bit. Here's the thing after it was almost running with the starter cranking still. I held down the pedal it bogs a little so I start pump the pedal and it doesn't help. After five or ten seconds of these almost starting/bogging symptoms. It completely just bogs down and doesn't even come close to starting again. Spraying more wd40 seems to help but I'm out now so until I get more I won't know. Also trying to start without it I can get the engine popping but when hitting the pedal it bogs. I've done the valves recently back in December. So I'm wondering if the bogging is from the piston firing to early on the upwards compression stroke?

If I take off the valve cover and align the tdc mark on the camshaft. On the crank pulley I should be able to tell how far out of time it is right?
From what I understand of using this method more than ten degrees out needs to be adjusted?
If I do adjust it by taking off chain tensioner and chain but leaving the camshaft in tdc position. Only rotate the engine clockwise at the crank pulley till it is at tdc, while holding chain tight. Would it align the IP as well?

Before I did this injector pre chamber work the car started kinda hard but was actually starting easier than ever and started right up first try after sitting for twelve plus hours in thirty degree weather the morning I did the work. Drove fine too. So I'm having a hard time wrapping my head around what's going on here. Unless the car has been out of time running on some working fault of the pre chambers or injectors. Now that they are operating more efficiently it's causing the timing issue to be more apparent?

That's my theory anyways let me know what you guys think.

When you line up the Camshaft Timing Gear Mark with the Mark on the Front Camshaft Bearing Tower that really only gives you a rough estimate telling if the Camshaft Timing is off compared to the Crankshaft.
Don't expect (OT) Top Dead Center to line up exactly due to Timing Chain Stretch and Timing Gear Wear.
The most accurate way to determine that is the 2mm Method.

The Fuel Injection Pump timing is a different Ball Game. Because the Camshaft Timing can be within normal limits but the Fuel Injection Timing can be off; especially if you removed the Fuel Injection Pump and did not get it back in the proper position.

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84 300D, 82 Volvo 244Gl Diesel

Yes, the black disk "or piston" orientation isn't obvious. If you stare at the FSM drawing closely (search Google Images), I could barely tell how it orients.

When you operate the hand pump with #1 delivery valve out, whether you get flow or not depends on the where the crank is. Indeed, the angle where it first stops flowing (or 1 drop/sec) is the "drip method" of IP timing. Factory spec is at 24 deg BTDC, but I set both engines to 27 deg since claimed better performance (couldn't tell).

I don't recall ever seeing the level dropping down when I stopped pumping. If so, that suggests a bad check valve. The check valve is probably in the Lift Pump exit fitting. The Hand Pump probably relies on that too. There is also a pressure regulator at the IP inlet, that I think is a "back-pressure regulator" (similar to a "pressure relief valve"). If working, you should have ~12 psig at the IP inlet, but to measure such people have had to tap into the banjo fitting. If much lower, the IP won't work properly. I am winging this description, so research to find the real facts.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

When you pump up the fuel using the primer pump. Does it become increasingly harder to do? At some point you then hear the relief valve open on the injection pump? Pumping pressure remains constant then? A slight squeal type noise perhaps. Finger applied pressure should be quite noticeable.

If this is so it perhaps might be time to remove the vacuum hose from the turn off valve on the injection pump. Or perhaps observe if the lever is not being pulled to the shutoff position pretty much as soon as cranking is started. I do not know what temperatures the car is being worked on but if too low it could make things really difficult.

Vacuum hose for decompression switch is disconnected for that very same suspicion. Also had my blowby hose disconnected from the valve cover as well. Neither have made a difference. I run a custom heated fuel filter setup and low pressure electric fuel pump for the lift pump. I don't wanna get into it on the mechanical mercedes lift pimp...but for me it's the bane of my whole existence on this car. No matter the precision on my rebuilds it always leaked fuel then after disconnected it leaks oil out the great big bolt on the end of your primer pump. I'm eventually going to block it off. But I have been running electric pumps for over a year now with no complications till now. I had a thought my old pre chambers where uber carboned up. Maybe they are flowing fuel better now exposing the early firing of the injector as more apparent in the almost pre combustion thing it mimics when I push the pedal down while crankinf? It causes it bog basically.

Also can you pump to much fuel to the injectors if the electric pump operates at a higher psi?

The reason I ask is several times I completely blocked of the return fuel line and it doesn't seem to make it any better. Also it's puffing white smoke like sunburned fuel while cranking.

Unburned fuel lol

I think I've finally cornered the main problem here. Awhile back I noticed my cam lobes had gotten worn slightly. On some of them one side was noticeably indented/concave. I'm haven't had a chance to pull the valve cover. I would bet my injection of fuel is getting stifled by early or late valve opening and closing. I'm ordering a new camshaft but I'm hoping a valve adjustment will do it. Also I'll check timing marks. I'd they're not off more than four degrees I'll try it. If that doesn't work I'm hoping I can bumb them a little left or right to correct the valve action enough to get it running.