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  #1  
Old 07-07-2001, 02:11 PM
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If they check out at .9 ohms, then they are obviously O.K. as far as the electrical heating element is concerned. But does this necessarily mean that they are definitely O.K. as far as to their FUNCTIONING? (Assuming that they are receiving currant.)

The reason I ask is that my 84 300D “misfires” on a few cylinders for about 10 seconds when started from cold. It also takes about 4-5 seconds of cranking even when warm. The compression is good, the valves are adjusted, etc. The car runs beautifully otherwise.

The injectors are original with 199,000 on them. Is it likely that these symptoms are indicative of the spray patterns or opening pressures being off?

Also, I have seen a tool for “reaming” the prechambers where the glowplugs are inserted. Is this a necessary or recommended procedure when replacing the plugs?

Thanks for the help!



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Old 07-07-2001, 08:56 PM
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It sounds like you might have a couple of injectors that are dribbling after shut down. You end up with a puddle of liquid fuel sitting on top of the piston when you attempt to restart. If the prechambers need reaming you'll know when you pull the glow plugs, they'll come right out of a clean chamber but you need to worry them out of a coked up hole. See if you can find a local shop to pop test your injectors for a reasonable price if you pull them and carry them in.

Bob D.
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Old 07-08-2001, 01:31 AM
nomad_diver
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injectors

i took my 78 into the shop and the mechaninc told me that the glow plugs and injectors often start to go around 150, 000 miles. mine had 187 on it with the originals. he may have been pulling me a bit, im not too familiar with diesels, but the new injectors made a world of difference. a bit costly though, 50 a piece for rebuilts. so yeah, id check those out. good luck!
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Old 07-08-2001, 04:21 AM
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hey nomad

just got a couple of questions....was your 300D really loud before you changed out your injectors (like clattering and idling rough)? what kind of changes did you notice that was really huge when you swapped out your injectors? I am very tempted to change out mine since all mine arent all the same....I got some injectors from a 240D in my 78 300D. I dont know what my dad did but when he had the car, he would only replace 1 injector at a time...not too sure if he did all of them.

Thanks for you replies
Allan

Oh P.S: the dots thats on your speedometer are correct.... I was estimating my MPH around plus/minus 5mph. sorry bout that
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Old 07-08-2001, 12:25 PM
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H20Diesel - your oppinion please...

Thanks guys for the input. MUCH appreciated.

H20Diesel: I kind of suspected the injectors since they have almost 200,000 on them. I am planning to go get some junkyard cores & bring them to an injection service place that has a great reputation for their rebuild services. They do all of the big rig stuff, and when I talked to the supervisor, he said that they rarely ever need to replace the nozzles. I was kind of surprised by that statement, but he said that if it were needed, then they would replace the nozzle as well. Otherwise, they regrind the nozzle seat (I think he said the seat), clean the orifices, set the opening pressures, and check the spray pattern. For much less than the bosch rebuilds; and I have read here that the bosch units are not necessarily very consistent in their Q.C. I like the idea of having kind of a ‘personal touch’ on something this critical & exacting – having one guy do all the injectors and setting the pressures seems like a good idea, versus an assembly line mentality that may be present wherever the bosch units are rebuilt. OK, I’m rambling, but I would value your opinion on this. Do you feel that NOT automatically replacing the nozzles is an acceptable practice, and are reground ones just "as good as new"?

Thanks Again!
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Old 07-08-2001, 01:17 PM
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The best way to check the glow plugs (GP) (except for the old style series loop GP) is to remove them and connect them directly to the battery. They should glow bright red in about 10 seconds or less.
The best way to do this is to connect a #12 or heavier wire to the GP terminal and clamp the GP to a good ground with a Vice Grip. Then touch the other end of the wire to the hot side battery terminal. If the GP doesn't glow red hot in 10 seconds or less, it is NG and should be replaced.
P E H
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Old 07-08-2001, 09:47 PM
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Glowslugs

RunningTooHot


Someone down the line gave good advice about checking glowplugs with a battery to be sure there is no internal short.Another excellant way kills two stones with one bird. Since you're toying with the idea of checking the injectors anyway,pull the injectors,turn the key to the glow position,and return to the engine compt and enjoy the show. Look into the prechambers and you should see each plug glow cheery red until the glow relay trips off. Also if you ever remove the head and have it machined you will need to install the prechambers with special spacer rings to insure proper depth from parting surface. Once this is done you ream the glowplug holes with a special reamer so the glowslugs will go in. Hope this answers some questions.

Peter
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Old 07-10-2001, 06:15 PM
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Thanks everyone for the info. I kind of like the idea of checking the glow plugs while the injectors are out – that’s a new one (at least to me). Maybe it’s because I didn’t get enough fireworks on the 4th.

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