Hello everyone, a little over a year ago now I manual swapped my 240d after the automatic blew out and love it. However, when I do 0-60's I'm still doing 30+ seconds on my times like I have an automatic. I hear people with 240d 4 speeds can do 0-60's in low 20's with a strong engine I'm assuming. I have great low end power in first gear, but by the time I'm in third with my foot to the floor the car winds up between 40-60mph like it lost its power.

Here's what I've done so far:
Throttle mechanism goes to the stop on the IP
Changed both primary and secondary fuel filters
Valve adjustment
Lift pump was rebuilt a few years ago with new hand primer
Overflow valve spring is set to 30mm
Air filter is pretty clean also

My assumptions for low power:
Dirty tank strainer
Needs a diesel purge
Poor fuel injector spray pattern
IP adjustments are off (I doubt it but I'm just hypothesizing)


I recently pulled the fuel sender to clean it and found lots of gunk after 30+ years of algae buildup in the bottom of the sender. I'm wondering If I should pull the fuel tank strainer since its the only filter that has not been cleaned in the fuel system. I have never done a diesel purge on the car either, so thats on the table too. The car also misfires sometimes at idle and I wonder if that has anything to do with the tanker strainer being clogged.?

One final question I have is can you clean the fuel tank with it in the car? like pull the strainer and use a garden hose to clean all the gunk out into a 5 gallon bucket or will the water puddle in the tank and it will never come out?

Everything you haven’t done is pretty significant.

By all means, pull the strainer. Re: cleaning the tank, the question will answer itself once you’ve examined the strainer.

When did you last clean your injectors?
What’s your IP timing?
How much chain stretch?
What’s your compression like?

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1981 240D 4sp manual. Ivory White.

@Shern The car has never had the injectors pulled or tested before. Me and my father have not done a compression test to my knowledge. The timing chain was replaced in 2014 by an ASE Master mechanic so I know that the timing chain is good. I have run biobore and startron to clean the fuel system but I know that is not going to deep clean the IP or the injectors like a diesel purge. We have also never done anything to the IP timing since we have owned the car

Regarding cleaning the tank, I'd certainly avoid trying to clean it while its installed in the vehicle. It isn't too big of a job to remove one, just a messy job as you almost are guaranteed to bathe in diesel. I've flushed out a few tanks with a hose (when the tank is removed from the car) but they are typically prone to rusting so you want to make sure to dry it out before reinstalling. I've taped a hair dryer to the stem that the diesel nozzle goes inside of and left it for hours to ensure its dry in there. I also know some 240ds came with plastic tanks but pretty rare. Maybe you have one of those, who knows.

I don't think its possible to flush the tank when in the car for the record, you'd never be able to get the water out. As for the culprit of your issue I'm not sure but the tank is never a bad place to start.

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Well, those things are all pretty vital.
If you’ve a tired engine with retarded IP timing and peeing injector nozzles, nothing else is going to make much of a dent. Diesel purge isn’t a bad idea but it’s not going to shave any time off that 60 run.

I’ve got my 240 down to around :18.
All of the things I’ve mentioned are in order: good, even compression, rebuilt injectors, IP timing at 26 degrees. I’m also running aluminum wheels and euro bumpers which contribute a significant weight reduction.

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1981 240D 4sp manual. Ivory White.

Take the car for a drive. Coast to a stop. Check your wheel temperatures.

If you have no history on the injectors. Removing them and having them checked is not a bad ideal. They may or may not need a rebuild.

I would check the injection pump timing just in case it is retarded.

I have all 4 four factory aluminum wheels the 240d came with and also have done significant brake work in the past year so no brakes are dragging. What is the procedure for checking IP timing? If I find out I have a strong and healthy diesel engine then I can go forward with power improvements, if not then I'll have to live with it.

Best to look it up in the archives. It is called drip timing. You really would just be checking it. Only adjusting the injection pump if it was out of time.

Subscribed as I want to learn your eventual problem .

I never trust anyone else to do anything properly, I paid a guy to time my 300CD's IP and it too was sluggish , Rich helped me test it and Lo ! the IP was way retarded, bumping it up made the car run very well indeed .

X 10 on pulling the injectors and having them pop tested, especially since it has an irregular miss @ idle .

Consider having greazer build you a set of injectors, money well spent in fuel economy and smooth engine operation .

Remove and clean the in tank sender, all you need is a toothbrush and some good strong soap like "AWSOME!" from the .99 CENTS store or the blue degreaser @ Sams Club, BE SURE TO LET IT DRY FULLY BEFORE RE INSTALLING ! .

A tiny bit of moisture will damage the injectors .

If the in tank strainer is nasty, take some time to find a 300D tank, junkyards usually have them, they're bigger yet bolt right in , you can clean it out at your leisure and install it, go 500 + miles between fill ups.... .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Dropping 10 seconds for a 0-60 run is a pretty bold claim without some sort of proof.

The glow plugs are there to help the car start. Up until the late 80s, MB diesels didn't even have after-glow, so as soon as the engine cranked, they were out of the circuit. Rough starting/cold idling is due to poorly adjusted valves, low compression, lousy injectors, timing issues, or air ingress into the fuel system.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

There are all kinds of discussions in the 24Valve Cummins world about 2 stroke being necessary to help lubricate the injection pump. I believe that it hel[s that engine and run 1 oz per gallon of fuel. Look up "diesel lubricity study" if you're interested. There was also a guy on the forums who pulled and compared injectors run with 2 stroke to some run without 2 stroke and concluded that the oil did not harm the injectors.

That said, I religously add oil to the Cummins but am not consistent with the 617 engines. I note IP issues have decreased on Cummins forums and surmise that rebuilders may have adjusted to ULSD and many people have had to replace their pumps. I have about 100,000 mi on my current IP without trouble.

I doubt that a dose of 2-stroke makes much difference in acceleration with the mechanical IPs. I note that it isn't critical on a Cummins 12 Valve, only the 24V.

Buy the cheap stuff in the gallon from WallyWorld if you decide to go that route. SD tank is 15 gallons so add 1/2 qt to the 1st tank. Fill up and add ounces depending on however many gallons of fuel you just bought.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Thanks you, that makes good sense .

I'll ponder it, I currently add Biobor to every fill up .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Lots of reading on this subject Nate, here in the archives and elsewhere.
Seems to have been a hot topic 10 years ago.

I’ve been adding 2 stroke (tcw-3) for a few months.
Absolutely quiets down the IP. Some make claims about economy (or power) though I’ve not noticed anything significant since doing so.

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1981 240D 4sp manual. Ivory White.

But that's nothing new....

O.K., I'll go buy a bottle of synthetic 2 smoke oil for Motos / chainsaws etc....

Give it a go, see what happens .

I should pull the injectors out and pop test them but I'm getting lazy in my old age .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better