Hello! I have an 87 300d with the om603- I’ve had it for almost 7 years. I have barely driven it for the past 2 but it never gave me issues until now. Any help would be appreciated. I’m kind of rusty at this point with it.

About a year ago it seemed running slow & shifting a little hard. Took off the alda & it shifted great & of course had more pick up. Put 200 miles on it from feb- may of last year. It sat until September when I did a diesel purge before I changed the injector nozzles. After the purge it was fine and sat until Dec. I went to drive it home in December from my shop & it had no power and wouldn’t rev past 1500rpms. I was taking it home to put the monark nozzles on & do the delivery valve seals. Just got done the nozzles & seals today and no difference.

Nozzles / dv seals torqued. I have a #22 head & torqued injectors to 22ftlbs. Turbo spins freely. Put the Alda back on. Was unmolested and I turned it 1 1/2 turns. Didn’t see any fuel leaks. Didn’t see any bad vacuum lines - all new as of 2 years ago. New air filter.

Could this be the injection pump? It was on “e” before the purge & put almost half tank new fuel in back in September.

Does it rev past 1500 RPM in neutral or park? When's the last time the fuel filter was changed (don't forget the O-rings on the housing bolt)?

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

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

It revs to right around 1500rpms in park- didnt try nuetral. Both filters are new. I changed them right after the purge.

Have a helper press the accelerator pedal to the floor and make sure the rack lever on the back side of the IP is actually moving to the full fuel stop. It's certainly possible that something is wrong and preventing movement of the rack lever.

Also, even though it may sound stupid.....have you checked for a mouse nest or a rag or something caught in the intake or airbox? It happens...

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

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

I’ll check that tomorrow. I just put a new air filter in and had all the intake hoses off to check the turbo.

Make sure the stop lever is fully vertical when the engine’s running.

Remove the plug in the #1 exhaust runner (takes a 17mm socket). If the engine breathes better, the exhaust is clogged. Likely the oxidation catalyst. Or does this car still have a trap oxidizer?

Sixto
98 E320s sedan and wagon
02 C320 wagon

The stop lever is vertical.

The car will rev to maybe 1700 rpms & holds at a max of 1500rpms. I removed that plug as sixto said & it raised everything by 1000 rpms! I’m assuming the exhaust is clogged. No trap oxidizer. Is that the cat right before the rear section of the exhaust?- basically at the end of the mid section pipe?

The catalyst is at the end of the downpipe before the flange behind the transmission.

That cat clogs for a reason like running rich or oil consumption. That’s for another day, I suppose.

There might also be a banana in the tailpipe.

Sixto
98 E320s sedan and wagon
02 C320 wagon

Could you have disconnected a hose on the switchover valve or maybe it is bad? Or the plastic hoses are switched?

Rat's nest in the exhaust?

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

I'm with Sixto on the cat being possibly plugged. After you did a purge did you take the car out and run it hard? It may well be plugged. remove the plug on the front of the exhaust manifold (made for pressure checking the exhaust line) and see if it runs better.
If so then you may want to do a Cat-ectomy!
DDH

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Thank you again Sixto! I had a horribly clogged cat. Have t driven it yet but it seems fine with the exhaust off. Can’t believe it clogged so fast. I assume the removal of the Alda accelerated it? Anyway thank you all for the help. Much appreciated.

too much fuel producing soot probably plugged the CAT.
you have two choices, drill out the matrix in the cat, if you want to do that it requires a long drill bit on an extension, preferably a half inch drill motor and a long nosed pliers to twist off the mesh as pieces of the ceramic material break off, or a new CAT.
Bought a car that had been driven frequently in short distances, not allowing the CAT to heat up. Tried a Italian tune up but still sluggish.
I dropped the exhaust line and tied putting a propane torch to the plugged CAT thinking that might burn off the crud but it didn't work, a futile effort on my part. That's when I learned how difficult it was to remove the matrix. Surprisingly little increase in exhaust noise though.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

I think the main problem was having the Alda off & only driving it 3-5 miles the majority of the last few years. I already knocked out the cat with a hammer & screwdriver. About 1/8in of soot on some of the pieces that came out.

My 300td would only rev to 2200 rpm's easily and 3000 rpm's max. It was slow as a dog when I bought it to say the least. A few hours later after breaking apart and removing the cat material it completely transformed the car and would rev willingly!