Now maybe 7 years ago, my car was having a problem going up hills. To make a long story short, I found out that it was because I needed to do a Liqui Molly diesel purge on it.

Now maybe 2 years ago (5 years later), my car was having problems going up hills, I did a diesel purge on it, and the car ran fine again.

Now the car is having problems going up hills again, but it's only been 2 years since the last diesel purge. Since this time between needed cleanings is shorter, I wonder if my injectors need replacing? Maybe mine are just worn too much or something. I found that I can get the injector nozzles really cheap, like $10 a piece or something. Would that fix my problem, or should I just do another diesel purge? I know diesel purge is a cheaper way to go, I just didn't know if new nozzles would make a robust change in power or not.

1991 300d, 256,000 miles

I am speaking of vehicles that only use diesel fuel.

Personally, I am not sure what the diesel purges did to supposably fix the issues in the past.

Lots of diesel engines out there that never have any sort of purge done on the other than occasional additive in the fuel tank. When there is the slow down you are speaking of what I was taught is that it is most frequently a fuel supply issue.

Things that effect your fuel supply:
Plugged or plugging filter
Plugged or plugging fuel tank screen
If the fuel tank venting system is plugged
The fuel supply lift pump needs to be rebuilt
A problem with the fuel pressure relieve/overflow valve not holding the proper pressure (The spring inside gets weak over time, and some have plastic parts the warp or fall apart.
Crappy contaminated fuel

Unfortunately, there is no easy way to check the fuel supply pressure.

__________________
84 300D, 82 Volvo 244Gl Diesel

I would replace the fuel filters and see if the sutuation changes.

__________________
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 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Have you ever adjusted or removed the ALDA? That's what finally cured my sluggish 91.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I'm surprised nobody said anything about injectors.

No, I never removed the Alda and I don't know how to adjust it.

They are not something I know cause the symptoms you mention.

One I missed was if there is an issue from the accelerator pedal to the throttle arm that keeps the throttle arm from going into the position it is supposed to be in that will slow you down.

__________________
84 300D, 82 Volvo 244Gl Diesel

What’s your process for doing the purge?
Are you replacing both filters afterwards?

__________________
1981 240D 4sp manual. Ivory White.

The only "purge" I have ever done is when I change fuel filter is I fill it with ATF before installing it. ATF is 'extremely' high in detergents & it does work. I do this with both my MB & Blazer.

__________________
"I applaud your elaborate system of denial"

Probably because injectors won't cause the problems you're having. They'll cause noise, they'll cause smoke, they can cause rough running, but not low power.

You have a fuel starvation issue or a boost problem. You mention nothing about ever replacing the spin-on fuel filter. Low power is a classic symptom of one that's beyond time for replacement.

__________________
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's basically only one way to do a purge. Disconnect incoming/outgoing fuel lines, put them in the diesel purge, and start the car. You don't have to use a full bottle. Half bottle will do about the same job.

Afterwards, change the filters.

I replace the filters on a regular basis. I think the big one is supposed to be changed every 12,000 miles and the small ones 3x in between, so every 4k miles.

This is true. However in the interest of being thorough, it’s worth asking.

__________________
1981 240D 4sp manual. Ivory White.

Being a 91, have you checked all the vacuum lines? The turbo wastegate is vacuum controlled instead of intake pressure controlled like the om617.

When I had my w124, I followed the vacuum controlled wastegate change over to pressure by following GSXR's write up on how to do that. I also did the EGR delete.

__________________
RRGrassi


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

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

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

Purging them would have no effect.

__________________
84 300SD
85 380SE
83 528e
95 318ic