When I am under 1/4 tank of fuel, the car is noticeably sluggish, and also more noisy. I also sometimes (usually rare) go to hit the gas and very little happens. (floored gets ya to 20mph and normal rpms for 20mph). When that happens i hold the pedal to the floor and in 15-20 seconds I can feel the fuel start to slowly come back up to its normal flow rate.

Im guessing this is a pump issue of some sort.
All fuel lines are unclogged.

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OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.

Clean your tank strainer.

Its probably the tank strainer, my old SD used to do that once in while.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

You sound convinced.

It is illegal for me to work on my car on the street here (chicago)
Anyone know what that would cost at a shop?

And thanks

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OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.

He always sounds convinced...........whether he's correct or not.

But, in this case, he's very likely correct. The SD would do similar with a partially plugged screen.

A shop can do the job in one hour with the proper tools. Just make sure you bring it to them with the fuel gauge on the "E" hash mark.

you can easily check if the strainer is clogged. just undo the hose connection to the hard line from the fitted hose on the bottom of the tank. if fuel runs freely the tank strainer is not clogged.
of course it's much easier on a lift but i have changed a fitted hose in the driveway without jacking the car up.
(wear old/disposable clothes!)

you might also have a clogged tank vent line .. you could check that too.

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

but have you checked the tank vent? When you open the fuel cap do you get a rush of air into the tank? these cars have a sophisticated venting system that can get clogged. If you get that rush of air into the tank, that is your problem.

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"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
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Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
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'92 Subaru
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'71 Buick GS conv
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Instead of cleaning the tank strainer simply go under the hood, drivers side and switch the return and feed lines. Then you'll be blowing UP through the strainer. The line seems to go to the bottom of the tank. Did that to my 240 a year or two ago and have run it fairly low on fuel with no problems. The reason I switched was because I could not get the strainer out to clean it.

Vent is a good suggestion too.

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Cheers,
Bill

there's your problem... you have a gas pedal and not an accelerator pedal. go to a junk yard and get the correct pedal

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-Trevor

OBK #12
1980 300SD 333,XXX miles - Totaled
1986 Mazda RX-7 212,XXX miles - impounded and auctioned off
2005 Jeep Liberty CRD Limited 33,000- SEGR, Provent, Fumoto

but you dont want to be sucking in the unstrained fuel. Make sure you have an extra primary filter, or just clean it out with brake cleaner

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1981 300SD 512k OM603

That will only diagnose the problem, it won't fix it. The strainer is there for a reason.

I did install an extra one long before I switched just because I like clean fluids.

I rinsed them out once with mineral spirits. That was when I first switched and have had no problem since. Haven't had to do so since so I guess whatever gunk was clogging up the strainer is gone.

Next oil change I'll switch them back. Correct that it is there for a reason.

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Cheers,
Bill

Haven't been able to check the tank vent or strainer as yet.
However today I noticed the GolfTee sticking in the port on the side of my switchover valve was missing. (Previous owner played with EGR) Dunno the last time I checked it.
It musta fallen out along time ago, as I've been used its sluggishness for awhile.

I replaced it and have ALOT more firmness to the accelerator pedal, as well as massively increased go-power from standing.

Im talking about regular slow excel, not the under 1/4 tank problem.
Im at 1/2 tank and will have to wait a bit to see what happens when I get low on fuel now.....

Can someone fill me in on the why of that?
Also, Was that possibly also related to earlier problem?

Am I trying to connect unconnected things here or am I onto something?
The sun is round. An orange is round. The sun is orange, thus an orange...
Must be the sun!


Going out on a beat run.... again.
I had no idea my car could perform this way. (AGAIN!)
Woooooot!

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OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.

What switchover valve? There is one mounted on the firewall used for over boost protection.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Its labeled switchover valve/ vacuum converter.
81 on following schematic...






Months ago Brian told me to
"Remove all vacuum lines to and from the following components:
81,64,60,71."

I was having other problems with the car and didn't want to mess with anything else before fixing the first problems... and never got around to it.

Just looked up that post to get the schematic.

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OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.