I have noticed that my 300d is a little shakey at idle. I notice it most on 100% #2 diesel. I ran out of fuel today on my trip and went into survival mode to get to a fuel station. I dumped what I had into the tank to get me to the station. I had 1 gallon of 10w-30 and a qt of trans fluid. Anyways, that worked great! But here's what I noticed... It instantly smoothed out. Then I filled it back up on diesel and it's shakey again. It's not an audible miss but I can feel a pretty good shake while sitting at a stop sign or in park.

Is this normal? Is my IP worn? Why did it run smoother on the motor oil?

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

How are the filters? ATF is a powerful detergent. It will loosen varnish or gunk in the fuel tank and lines.

I don't think your IP collapsed from running a gallon of engine oil and some ATF but you might have some seals that didn't enjoy the odd blend.

Sixto
87 300D

Happy thanksgiving everyone!

Sixto:
I actually noticed this shake long before I did the oil and trans fluid save when we ran out of fuel on the road. Now I know to fill up when I see a quarter tank! It's the first time I ran that low on fuel and this car is still pretty fresh to us. First long road trip for sure.

But when I had the IP timed at the dealership I had a 50/50 blend of heated and filtered WVO/Diesel.

Could that have an effect? My thought there is that maybe it was timed for a more viscous fuel since I had the half and half blend. I'd bet the pop pressure is the same but the time it takes for the oil to pop the injectors is a little slower.

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

The time that it takes a pulse to get from the pump to the injector varies the timing, known as "port effect", but wouldn't be affected by this change in viscosity (not noticably).

It might have more to do with the energy in the fluids (BTU) or the cetane (slower burn = higher cetate #), even possibly affecting the idle speed slightly.

__________________

Gone to the dark side

- Jeff

Ok that makes sense. So the slow burn Veg oil or Motor Oils could create a longer smoother stroke thus a smooth running idle.

Do you other 87 300d guys have a little shake at idle or just me? My idle RPM is around 650 or so.

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

If the vibration is higher frequency almost like a buzz, it could be worn engine mounts. You can eyeball the gap between the support arm and the frame. Anything less than 1/2" means the mounts are worn. At least that's what I remember reading.

If it's a lower frequency lopey idle that makes the whole car bounce, that's more likely isolated to a cylinder or two.

Sixto
87 300D

I think it's a lopey idle as you said. It's smooth as a top (no bounciness at all) when the car is run on oil of any kind. So I think it's injection related.

On diesel it feels a little shakey. Probably not hurting anything though. It'd be nice if it were smoother.

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

Got it figured out... Turns out the IP doesn't run as smooth on Diesel heated to 80C. So I put a shutoff to the heat for when I have no Veg Oil in the tank. I'd imagine Diesel's a little thinner at that temp. As far as burn rate/btu etc. I have no idea how heated Diesel does in terms of those compared to unheated Diesel. But got the shake fixed.

Just had to give that post an update.

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

Motor mounts? Engine block shock absorber?