Okay new with the 84' 300D Turbo Diesel. Has 168k two owner car garaged it's entire life. Just bought it last week I am the third owner. Seems to have trouble getting up to about 20 miles an hour, once it gets there it will get on it.
Anything I can do? Should I floor it when I am ready? Appreciate the help for this rookie.

Take and check the banjo bolt in the back of #5 intake runner. This is for boost enrichment and will make 617's flat as all get out.


You also can adjust the alda a bit but check the banjo first.



Joe

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Sounds good not sure what you mean by the Banjo Bolt nor do I know where the #5 intake is? What side of the motor? Thanks for the patience

A banjo bolt is a hollow bolt that goes thru a fitting on the end of a hose (the banjo). There's some in the fuel system and one on the boost line which comes out of the air intake, which is on the pass. side coming out the end of the intake towards the fire wall. If it's clogged enough you'll need some solvent and maybe air to blow out the boost hose. Don't lose the sealing washers as you pull it out, there is one on either side of the fitting

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'84 300SD veg-oil bliss
'83 300SD veg-oil beater

You mean to tell me you DON'T floor it?? That's your problem right there!

Rev the snot out of that machine, that's what it was made to do.

For an automatic transmission diesel, there should be no "pedal" AFAIC, it should just be an on/off switch. Light turns green, ON (fully).

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1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

No I do floor it. Was wondering why is it sluggish out of the hole. Does not seem to matter if I floor it or not. Thanks.

I must have some secret, hot-rod diesel mercedes produced. I don't think I have ever floored my '84 because it really has a lot of pickup. Even from a standing start I can easily pull away from traffic behind me. That said, my car is an '84 california version, and I suspect it has a different rear-end gear ratio than others. My car seems to rev higher than others on the highway.

If your car is really that slow, you should investigate. A major tuneup would probably really help - all new filters, a valve adjustment, a new wastegate hose, cleaning the banjo bolt and vacuum line, etc. On the other hand, if you don't know where the #5 cylinder is, maybe you should have a pro look at it.

GregS
'84 300D
'90 300CE

Hey Greg,

Thanks. I figured out the number 5 cylinder is towards the firewall correct? I will get all filters checked out and have the Banjo Bolt looked at as well. When I check it what should I exactly do? The car is great like I said once it gets going.

on my SD and I believe your car too the bolt is is threaded into the firewall side of the intake manifold. If you look at the back (firewall) of the intake manifold you will see a plastic tube running around to a bolt head there. That is the banjo fitting. The bolt is quite long and is I believe 12mm. You unscrew this bolt and then remove it saving the washers that are on either side of the fitting that the plastic tube connects to.
This bolt is hollow and allows for the injection pump to sense boost from the turbo and give the engine more fuel top burn.

Clean the bolt out and I usually take a piece of wire and clean the hole to eliminate any blockage that may be building up inside the manifold. Screw the bolt back in and do NOT overtighten it as with a hollow bolt it can snap off.

Make sure that the plastic line coming off the fitting is not blocked with crud either.

if this does not change things then it might be an alda (altitude compensator on the injection pump) related problem. These are delicate instruments though and can be easily broken so you might want to do a search on this forum and read up on it before attemtping anything there.

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'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

That is great Fisherman. I will do as you suggest definately. I bought the car in a town called Twin Falls in Idaho. Probably about 3900 in elevation. I live in Sun Valley so it could be the Alda if that is the case should I take it to a mechanic? The elevation here is about 5400.

Also, if you follow where the plastic hose goes to you will find the 'switchover valve'. This valves mission is life is to vent the pressure going to the alda (which lets the injection pump know you have boost) when there is an overboost situation that might damage your engine. Occasionally people have had the valve stick open in the venting position and as far as the engine is concerned it isn't generating any boost and won't provide any extra fuel to increase power (same reason for checking the banjo fitting the other members suggested). As a test you can bypass the valve and notice any performance difference.

The ALDA is the square piece of metal with a nut and screw in the center. The plastic tube from the switchover valve connects to the ALDA. To adjust the alda you loosen the nut and turn the adjustment screw CCW. Be carefull to remember where it was just in case your car starts excessively smoking off the line. Living as high as you do I imagine your car is just going to be a slug untill the turbo is able to push some air into your engine.

G'luck and let us know!

John
'79 300SD(2)

Tymbrymi
Thanks I will also take your advise and see if that takes care of the problem as well. Now, the Alda is not self adjusting it sounds like. Are there any other areas I need to be aware of? Sounds like what you have mentioned and what the other advice has been, I feel I should be able to handle. Let me know and I will definately let you know what the outcome is. Thanks

Being in Ketchum you probably won't be able to find a wrecking yard with parts so make any adjustments on the ALDA minor. If you go too far and break it there is no fix and they are not cheap...

Just a little reminder. As far as the altitude you should not have a huge problem unless it was not set properly or that the settings have changed over time due to weakening of springs etc internal to the ALDA.
It is there to adjust for the changes in altitude automatically. You may very well get a big lift with a minor adjustement on it.

Have you considered picking up the manual for the car on CD? You can get them off ebay and they are usually like 15 bucks. Great investment if you plan on doing much yourself.

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'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

My 300D is a rocket compared to my 300TD...so, after a fashion, I've been fighting this same issue for a year, doing all the same things recommended here with no significant improvements. But, I think I'm finally on to something. Do a search of the diesel forum for the following: "near dead miss at idle", "psfred" and "pressure valve holder seal ".

Or go here: Near-dead miss at idle

Good luck!

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Fisherman,

Great idea was thinking of trying to find one, CD would be best. Found this website which is great so wanted to see if I could do anything form here. Finding a CD or book I would expect to be pretty easy on eBay right?


Thanks for info on the ALDA, good to know that it should be self-adjusting.