first set is from initial attempt - no repairs yet

second set is after smashing around for retest

third set is after a dry compression test (150psi #1, 150psi #2, 175psi #3, 175psi #4) and the following repairs
IAC good and clean
R16 resistor proper and in place
new non resistor plugs bosch H8DC gapped to .032 (previous owner had installed resistor type)
new cap, rotor and wires OEM
new O2 sensor OEM
duty cycle adjusted to 50%, last measured was 53% right before the smog test (1 - (6.45 avg at the X11 / 13.77 at battery)*100)

no EGR equipped

car doesnt eat oil but sometimes find a teaspoon full in the corner of the air cleaner box - too much back pressure forcing oil through blow-by?

cat condition unknown, looks relatively new, tapped on it with wooden handle from mallet, doesnt rattle, has a 'ting' sound

timing supposedly at 16 btdc but have no way of confirming - timing is non adjustable correct?

please help! im thinking misfire but idk what's causing it after finding good compression and replacing most of the ignition with proper pieces

one more clue, on occasion but not often, she will drop rpms normally but stall out around 500rpm if clutch is put in at 4k+ rpm. will drop normally and ALMOST stall out if clutch is put in at 2.5k and below. this scenario is repeatable with car completely stalling from a 4k drop but will not stall from a 2.5k drop.

Since NOx is the only reading that is too high.....most likely the catalyst is to blame.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
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MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

If I am reading the sheet correctly, looks also like HC is double the limits as well?

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

yeah thats what is making me think misfire, the catalyst is using more of the available O2 by the third test and i still have a bunch of unburned HC and a metric **** ton of NOx! the mix had been very lean before i got the new O2 sensor and adjusted it. it was like 20 something percent!

im thinking timing and a clogged cat but i just want more opinions before i drop 4 bills on a new cat and itll still prolly not pass

The cat is only there for cleanup of small amounts of excess pollutants. Sometimes when you see double/triple/++ the limit, all that blame cant be laid on the catalyst. And emissions shops throw cats at cars first thing, and yes a brand new cat will probably mask most engine problems. But next time through emissions you might not be so lucky. It also seems that most Benz engines from this era are very clean running when in good tune.

Did you adjust duty cycle with the engine warmed, running, at idle? Does voltage fluctuate pretty quickly on the voltmeter?

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

yes i followed the landiss webpage mixture throughly. it was adjusted after being warmed up at idle initially then checked against 2500rpm to make sure it is within +-5% to +-10%

i could rent a timing light but i dont know where any marks are, the only ones i know of are under the valve cover on the cam sprockets

no, there are timing marks on the front engine pulley (going from memory on my 86 190E)

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Prost!

OK, I'm human & just missed the HC reading twice the max allowed..

Since the HC's are high as well...What was the last time the valves were checked & adjusted??
The front 2 cylinders are much lower than the last 2....25 lbs of compression is a BIG difference.

Timing can't be adjusted! ONLY make sure that the rotor is indexed properly.
At TDC the rotor should align with the punch mark in the distributor housing.

TDC IS marked on the balancer....O/T is the marking.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

thank you, ill get the timing up proper. the engine crank bolt is 27mm right? when i line that up what do i look for on the distributor?