Trying to get my 1988 2.3 190e to pass emissions,,, Am running out of ideas, other then replacing the cat,,,

On the 25 MPH test this car registered 2856 (1313 max) NOx and 225 (181 max) HC,, CO passed with 0.40 (1.16 max) CO2 was 14.35%

So I'm wondering, if the ticking I hear might be the cause of the high readings for NOx and HC.

On another note,,, I took off the oil filler cap (while car idling) and there was quite a bit of blowby,,, the car doesn't appear to be burning any oil (through exhaust) I've only put 100 miles on the car so I don't know if there is any oil consumption,,, but from the looks of it, the answer would be no.

The car runs good, a little vibration at idle, but no where near as bad as a domestic with 1/2 the miles,,, 247K miles on it.

Any input is appreciated.-

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anyone with knowledge wanna chime in???

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I'll take a shot, others can give their comments.

I read some of your previous posts and I think you mentioned some blowby and idle vibration. Probably caused by loose piston rings/valve guides or burnt valves which is not creating enough compression/combustion therefore the high HC. Shot at the moon tells me that the good cylinders are leaned out because of the unburnt O2 in the bad cylinder.

Did you do a compression test yet?

Valve lifter noise won't cause that emission problem..sticking valves (R burnt valves can..ie: low compression.

To start with the CO is high for that car..how old is the O2 sensor? Has the duty cycle been adjusted? How old are the plugs & were they gapped to 0.040"

IF all of that is OK...try a OLD remedy..a water tune-up

About 10oz thru the engine will make most cars that close to PASS.

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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

I've heard of this being done on old Chevy's that were carb equipped. In some cases the engine hydro-locked.

How does one feed water to a CIS system?

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

There must be a vacuum line somewhere, that feeds into the intake manifold.
Restrict ( pinch the feeder hose a little ) the waterintake.
Run the engine at @ 2 000 rpm while doing this.

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2007 C 230 Sport.

If it's an automatic, use the manifold connection where the vacuum line from the vacuum modulator connects.

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1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible

so let me get this right,,, I take a vacuum line off, stick the open end in some water,, with the hose pinched, I slowly let the engine suck in the water from the vacuum line,,, doing this at 2000RPM,,,

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sorry for the delay in answering these questions,,, O2 sensor replaced with one that fits a ford,,, I adjusted the duty cycle, but I should look at it again,,, Plugs (gapped .032" I think) I am getting low compression on 1 cylinder (105 PSI engine cold) the car runs good, but the idle isn't becoming to a Mercedes.

So you think the water treatment might work? you state 10 oz, how many minutes should it take to go through the 10 oz?

What does the "water treatment" do?

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Should take about 1 minute to feed the water through.
It will loosen & blow out any carbon build-up.
Don't be alarmed when you see lots of steam coming out of the tailpipe while you're doing this.

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2007 C 230 Sport.

Cools sounds like a neat trick,,, so what are the dangers to performing a water tune-up? If I put too much water in there can't the head gasket blow?

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No. Headgasket is safe.
Worst thing that could happen ( very slim chance ) is, you may blow a little piece of the sparkplug ceramic insulator off.

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2007 C 230 Sport.

OK Ran a compression test,,,

#1 = 105 PSI
#2 = 150 PSI
#3 = 150 PSI
#4 = 135 PSI

So #1 seems a little low,,, is this enough to cause the O2 sensor to over compensate?

I, just recently put a quart of Tranny fluid in the Crankcase to help clean out any sticking valves (Only have driven about 50 miles since I put it in,,,) also put a can of Guaranteed to Pass in the Gas, in hopes of cleaning up the valves.

Shy of rebuilding the top end, what can I do to reduce emissions by 30% to get a waiver?

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That low compression is MOST likely the cause...now why is the compression low?

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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

Hoping it's the sticking valve. I'm sure it's on the intake because I hear no noise from the exhaust side,,,

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