1981 300D

I always seems to be, I get a free day to work on the car and I can't get to my goal because some other issue comes up. Ugh!

Went for a test drive, came back, popped the hood and fuel was spraying all over the engine compartment. The little plug at the last injector is gone.

1. Is there supposed to be that much pressure in those lines? The fuel was easily shooting up three or four inches aff the injector. I'm wondering if there is some over-pressure thing happening with the IP that just blew the plug off (these lines are only about 2 months old). But then again, if there was too much pressure I would think it would dislodge one of the lines earlier in the circuit. Any thoughts? Maybe it just wasn't on tight enough.

2. I'm gonna go looking for the old one in the street now. If I can't find it, anyway to rig something up until I can get a new one?

3. Is there an "IN" and an "OUT" on the injectors? I just plugged them in in series with where the injectors were, but with two nipples on each injector, is one in and one out?

Thanks in advance!

Eric
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1981 300D

i just had the same problem and a member of this board is sending me extra return fuel line.. which injector is it.. #5 the one closes to the firewall or #1 with the line that goes back into the fuel filter

Here's what I did when I replaced my lines. You can buy the propper plug off of fastlane here. Since I'd already destroyed my last plug trying to get it off and I didn't think to have another to replace it, I was panicking thinking that this one little piece was going to leave me without a car for a week. Luckily at the time a thread was being kicked around here and someone mentioned screwing a screw into a short piece of hose and using that for the plug. I used a 1/4" self-tapping sheet metal screw. It was a little more than a 1/4" long and it fit in there snuggly. It wasn't a perfect fit, fuel still weeped ever so slightly, but it held for a week until the right part got here. So if you have any extra hose left over, give it a try.

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Seth

1984 300D 225K
1985 300D Donor body
1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!!
1980 300SD 311K My New Baby.
1979 BMW 633csi 62K+++? Dead odo

Don -

Its the one closet the firewall . . . the lines are all inact, its just the little plug that ends the series.

1: Yes, it's tapped into the main return line so they share the same pressure. About 1% of the fuel coming out of that line is from the injectors.
2: A nail, small bolt, golf tee, screwdriver tip, small stick, the list is endless. Anything that will fit into the hole.
3: No. It's all the same.

Good luck. It can puke ALOT of fuel out of that line when it goes, I hope you didn't go far.

Great ideas fellas . . . I had some old line and just put a screw in it. Works perfect, no weeping at all. Thanks!

Put a screw in it, that will work until you can get your hands on a new plug. Their isn't much pressure in those lines return fuel just runs through them. Can't be more then a few psi.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

A BB or a small ball bearing would work just as well as the original plug. Also a short piece of stainless steel rod, which is what the plug probably was in the first place.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

I had the same problem while I was driving the SD on vacation. I had set of hemostats in my tool box and clamped the line - it worked for 1000 miles until I could get a proper plug.

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1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer

This used to be enough of a problem that the service guys at Von Housen Motors in Sacramento would leave the owner a spare in the glove box. Mine is still there. Never needed it. They tend to get brittle from age and engine heat.

There is usually enough hose left over when you replace these drain hoses that you can make up a spare or two by cutting short lengths and plugging them with a rivet or small screw.

How the heck did it pop off?

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

I'm not sure how it popped off . . . I noticed on top of the IP that the hard steel line that feeds the cylinder before it had a bit of diesel at the base. It was super loose, maybe some air got pumped through and kicked it off? Who knows, but the replacement I made with the screw in the top works great!

Eric
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'81 300D