So, I am driving to TX this weekend from Pittsburgh, PA. I am in my 85 300D. I have not really had this car out on the open road before where I can open it up at a high speed for an extended period of time. What I found today was that it did not want to go past 80 mph. At around 75 it started to pulsate. On an uphill climb it started to do that at around 70. I am thinking that it is probably the air filter and the engine is starved for air. I looked at it and it does not appear excessively dirty but maybe it is clogged from all of the spring pollen. I am staying over outside of Cincinnati and will pick up a new air filter in the morning at the MB dealer which is on the way. My fuel filter looks clean. I changed the primary and secondary fuel filters recently.

Any other thoughts about what might cause this problem?

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85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

i would lean away from the air filter. whenever i had issues it was not air filter related but fuel filter. you said that you changed them recently, have you been running any biocide, biodiesel, or veggy lately?

all these items will cause your filters to be clogged faster by freeing it and moving it junk from your tank to your filters.

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Grey '91 350SDL 214k Dad's car
Beige '81 240D 4 Speed 254k SOLD
Blue '82 300D 225k SOLD
White '95 E300D 46k SOLD
Blue '87 190D 2.5 Turbo 315k SOLD
Brown '80 240D 4 Speed 716k SOLD
Beige '80 300D N/A 119k SOLD
Blue '85 300D Model 186k T-Boned

Just pull the air filter for a few miles will tell you if it is the issue. I doubt it is.

Have you ever cleaned the banjo bolt? 70-80 is where boost will start to become very important. A 240D will still accelerate up to 70 MPH, it is the top end power to do the higher speeds consistently that is where the turbo helps.

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

still, that "pulsating" part points me to the spin on fuel filter. it can clog in one fuel stop. time/miles are meaningless. it all depends on the fuel quality.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I have not run any biocide, biodiesel or veggy. I did run a cetane additive through at some time in the past year.

__________________
85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

I thought of that. I may try it in the morning.

__________________
85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

I have not cleaned the banjo bolt. This car has such low mileage, I would not have thought this would be an issue, unless city driving could get it clogged up that fast. I just turned 45K on the odometer today, believe it or not. There were years when the PO did not drive 1K miles, according to the log I inherited.

__________________
85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

Hmm. That is a good point. Maybe I picked up some bad fuel a few tanks back. It would be easy enough to put on a new fuel filter.

I think I will try one thing at a time tomorrow to see what makes a difference. I am hoping that between the fuel and air filters, one will change the performance. I have about 900+ miles to go and do not want to drive this way for the rest of the trip. I am also leaving the car with my son in TX and will not be around to help him if anything deteriorates between now and August when he finishes his summer job.

__________________
85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

Thanks for all the input. If I have free wireless again tomorrow evening where I am staying I'll log back in and let you know how it went.

__________________
85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

There's always help in the Memphis area. PM sent.

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
Cluster Needles Paint
New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

The 70 max may be a blessing given that you are leaving the car with your son !!!
When you find the problem, let us know what it is. I may wish to cause the problem on mine!!

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

This week, I drove from Anniston, AL to Altoona, PA round trip. I noticed intermittent pulsating right after my last fillup on the road. I assumed it was the fuel filters, so am planning on swapping them both out this weekend. And I did use some biocide, just this last week...

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Mine: 1987 MB 420 SEL - 62K (Dec 2019)
Mine:1991 MB 350SDL - 244K (Aug 2011)- Totalled 9/14/2016
Mine:1981 MB 300SD - 326K mi (July 1997)-sold
Wife's: 2008 MB C300 Sport - 92K mi (April 2009)

Pull the banjo bolt and check if it is clogged. Pittsburgh isn't a friendly city for stop and go traffic. It's definitely worth the 5 minutes of wrenching to check.

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-Typos courtesy of my mobile phone.

Just had the same problem on my 240D at highway speeds. New fuel filters fixed it.

I had run some 5 year old lawn mower gas in a 5% mix ....

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05 E320 CDI
99 SL500
02 530i

82 240D SOLD
83 240D Euro 4spd SOLD
86 300D Euro Auto SOLD