I'm currently replacing my injector nozzles and decided to run a compression test on my 85 300D with the following results:

#1 - 385
#2 - 375
#3 - 375
#4 - 385
#5 - 305

I tried pouring a bit of oil in the #5 cylinder and then, cranking it a few times to blow off excess then running the compression test again. When I ran the compression test again it quickly jumped to 600+ then evened out closer to 400. I think this means that cylinder ring is most likely to blame for the lower compression.

Anything I should consider trying here to help out compression on #5, or should I just ignore it and keep driving?

Can setting a different 'pop' pressure for injector #5 help balance anything?

Banish those numbers from your mind and keep driving.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

x2

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Hey,

Those are really good numbers except for #5. Did you adjust your valves before testing? If not, I would suggest that, plus you need to do it anyway. Check out the FSM as those number appear high. I think the max is around 350.

I did do a valve adjustment about 3 weeks ago.

OK ---

Well, there goes that bright idea.

I think the FSM puts the compression for a OM617.9XX engine at 319-348 PSI at 80C or 22 - 24 BAR (Bar = 14.503 psi), and give the engine at least 8 revolutions, so you are still pretty good or something is up.

I couldn't agree more.

__________________
2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

x 3 ...... keep driving and don't worry about the numbers on #5.

__________________
1983 300D, the "Avocado"
1976 240D, 4-spd the "Pumpkin", SOLD to Pierre
1984 190D, 2.2L, 5-spd, my intro to MBZ diesels, crashed into in 2002