OK, I just drove my '78 300D from Oklahoma to Ohio. Per another recent post, I installed new Monark nozzles, had them pop tested and balanced at a local shop (OKC). I had earlier complained about a loss of power on initial acceleration - which is still there - but the car runs great at 65-70 mph. I got 24 mpg's - a little disappointed with that...Prior to the injector change I was getting 24 mpg on the highway. Is that all I can expect from this car?

I also noticed that the engine was pinging - typically around 55 mph and when under load - a very noticeable "knock", or maybe more accurately a "ping". I don't think I have ever noticed that before... I didn't really notice it on this trip until after my last fill-up - but I may have just not noticed it before.

I have not had a chance to time the injection pump yet. I just received my drip tube, but I didn't have time to try this before leaving for Ohio - and I was a little nervous about trying it myself.

Any suggestions as to the pinging?

Thanks, Ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Bad diesel?

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

I would do the IP timing before messing with anything else.

I agree - IP timing. I'm just still confused about how to do it for sure - even though I've read thru the procedure several times. I have read 3 different sources - this board and the above DIY, the Haynes manual, and the FSM - and they are all a little bit different (the Haynes seems the easiest).

Ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Sounds like the IP timing is off a bit, you shouldn't hear a knock.

If the chain has never been touched and its got a lot of miles chances are its quite a ways off.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Since you actually have to check the timing before correcting it. Once you go that far you will have confidence in what you are doing. Go for it. You really cannot mess it up in my opinion. Once you do it once it will be like falling off a log thereafter.

It almost sounds like the pump is too far advanced if anything. Hard on the engine if so. A slight advance might give higher milage far too much advance would lower it in my opinion. The engine should not be pinging. Also diesels that are too far advanced can develop harmonic balancer problems eventually.

It somehow or other seems to apply or transfer some kind of shock loading. This I found out on volkswagon diesels. Do not forget to check and adjust the valves. The same rule applies. You check them first. Only adjust them if out of specification. .

One more safegard is to always make a couple of marks with a punch so you can put the injection pump back where it was if something unusual transpires like the pump has no clear shutoff point on the # 1 element but insists on leaking no matter where you put it. Unusual but things happen. Just follow the instructions to drip test the timing otherwise.

I just reread your post and noticed you have a non tubo engine. They are not as efficient as the turbo versions so milage is a little less as well as power. The pinging could easily be the last load of fuel. Yet the injector timing chain stretch etc should be done anyways.

Especially If You do not know the last time. Some owners just drive them as long as they run. This is not really reasonable with this model and you already own the drip tube.

OK, you guys have inspired me to give it a go. We are heading home next week, so I will try to check this before we leave (may be posting some questions as I go).

I checked the timing chain last time I adjusted the valves - which was right before we left. Chain only showed 3 degrees stretch (by aligning the marks - not using the 2mm valve lift approach). I did it several times and got the mark dead center and consistently measured 3 degrees...

Several techniques described for supplying the fuel - can I just use the pump? I also read about supplying the fuel from a can... That seems to me to be the most confusing aspect - controlling the rate of fuel. And I'm still not exactly

ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

I decided to wait until I got home to mess with the timing, so I'm going to try it tomorrow. We made the trip home w/o any trouble and several tanks of fuel later, car is still knocking. I added some cetane boost (Power Service Diesel Kleen) and I noticed knocking at mid-range speeds (50-60 mph), and when the engine was under some load. Didn't notice when cruising at 65-70 mph - car seemed to run better then (got my same 23-24 mpg).

While at my folk's house, I changed the valve cover gasket and checked the valves again. I noticed that almost all of the intake valves were too loose - exhaust valves seemed about right. Would this effect knocking? Timing chain shows about 3 degrees of stretch. Most of the posts I have read about this problem seem to indicate bad injectors - I guess it's possible that one of the new injectors is "off"... although I don't really notice any problem at idle.

ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Yes it is possible for rebuilt parts injectors or not to have problems. But from what you have described I got the impression more than 1 injector was pinging.

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84 300D, 82 Volvo 244Gl Diesel