87 260E failed smog...Input?
 

Any thoughts on what direction I should take?

All the moron said at the test center was I needed a new engine :rolleyes:
http://www.ps2cho.net/downloads/phot...E/smogtest.jpg

My compression is 185psi across the board.

Looks like the fuel system is out of adjustment...the O2 sensor/lambda....

The fuel mixture hole still had a seal on it when I got the car! Never had been touched! It shows 50% when I tested it though..

What about thoughts on the cat?

So start by checking fuel pressure and testing voltage on the O2 sensor?

How many miles on the car?

Was the Lambda fixed at 50% or was it oscillating around that value?

I'd put my bets on an O2 sensor problem if the Lambda is adjusted correctly.

Would a faulty O2 sensor alone really cause a GP?

It was oscillating, but around 50% at idle.

heres a cheat for you, if your car has an air pump. do a quick wiring job to make the air pump run while going through inspection. It will pump air into the exhaust giving you 0 emissions.

Hi Mike
I hope what u say is true, because mines failed miserably too.
My 90 300 se does have an airpump, to wire her on while going thru smog test is no big deal. It will cost me $23 to test, but is worth to validate your hypothesis. The extra air will burn off the extra hydro-carbon, reduce the CO.

I have already unplugged the air valve, it did improved the idle test.
Before anything was done, the car failed in just about all count. And the exhaust really stinks with too rich gas. Some guy offer me a used working O2 sensor for $40. I haven't had time to pursue it yet.
I live in Vancouver BC we have www.aircare.ca the good news is they will rendered emission test to become History in 3-4 yrs, as newer cars are so clean, so we'll be receiving our Get out of Jail free card soon, but not soon enuf. i wanna my cake & eat it NOW.:mad:
I hope I can give u good news very soon.
I have tried stud tires as a chap told me, with stud tires it wont be allowed on the dyno drum. But no serie Bob they did the test as if nothing had happened, or the poor testing employee had been rendered redundant already.
I do start to feel like I am WIley Coyote or Wicked weasel always try to beat the system at every instance.
pray I get thru. God help all of us.

No airpump on a 87..

Is it harder for the pre-'90 cars to pass smog since they don't have EGR or an air pump? Seems like that would be the case.....

MI rocks, no smog tests here! :D

NOx forms when cylinder temps reaches 2500F and higher which indicates a lean condition. A lean mixture will produce oxides of nitrogen since carbon monoxide and hyrdocarbons are down.

I would have the lamda adjusted and the oxygen sensor tested out. Then I would make sure the fuel delievery system is delivering a good amount of fuel.

I was at an auto parts store and chuckled but was curious when I saw not one but two different additives claiming to "guarantee" smog pass... :rolleyes:

Is it true that if you fail the smog test twice as a gross polluter they have to confiscate the car in california?

Should have my ignition wires and idle air hoses tomorrow so will put those on and see how it goes. Once that is done I'll start testing the O2 and Lambda. Wanna make sure I don't have a huge vacuum leak with these rock hard hoses.

anything for a buck, some people dont know any better or dont care to look info up.

The high NOx could also indicate a clogged EGR tube...

Dont think we have an EGR sytem on this one.

How many miles? Have the valve stem seals ever been done?

High NOx can be caused by high compression caused by deposits in the combustion chambers. High unburned HC can be caused by the oil running down the valve stems. Time for a head job? It has twice made my aircare numbers a lot better.

Andrew
1989 190e 2.6

I have checked the plugs and there is a little deposit...but nothing more than my 300TE had, and she passed the test fine...So I don't see the "cause" of the failure due to the valve stems.

Odometer is broken at 81k miles. I would make the assumption it is no greater than 120k because the head gasket or front timing chain gasket have not been replaced. Not much on this engine has been done. Even the mixture tower has not been touched. Had to grind off the top today to get at the unit.

NOx is too little air and too much fuel so a blocked egr tube could be in question. Any gas or diesel car Ive seen has an egr system on it...

he doesnt have a problem with HC..... he has a problem with NOx.Whenever you have high NOx hydrocarbons and carbon monoxide are down greatly.

This engine does not have an EGR.

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Why is my X11 reading 69.2% and not 70%?

http://www.ps2cho.net/downloads/photos/260E/x11_1.jpg
http://www.ps2cho.net/downloads/photos/260E/x11_2.jpg
http://www.ps2cho.net/downloads/photos/260E/x11_3.jpg

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Fuel pressure looks dead on.
Lower Chamber:
http://www.ps2cho.net/downloads/phot...ressure260.jpg
Upper Chamber:
http://www.ps2cho.net/downloads/phot...ressure260.jpg

your egr is mounted on the exhaust manifold and a switch overvalve is mounted on the wall. Ill take a picture for you. every car has a system in place to do the role of egr whether its mechincal or electrical(electrical egr, variabl valve timing(vvti) like in a lexus/toyota.

60% is road speed at ke control unit is an implausible-test hall effect sensor

70% is no tna signal plauisble, open circuit to ke control unit-test tna signal

btw you are supposed to do that after reading the fault memory @ x11/4

There was no EGR on this model year...In the later models there was one attached to the exhaust...I believe 90 and above? Someone correct me if I am wrong.

some info on the emission system for the M103

if you dont have an egr valve then someone must of removed it for performance reasons, but an egr should be there

I thought my RENNTech engine was unique in that the front exhaust manifold does not have any fittings or an air pump like both my 91's have but my new (to me) '88 300TE as shown also lacks these parts...

The '87 260E and his '88 300TE have no EGR system on them and I am pretty sure they have not been changed.

Can anone tell me the procedure for setting the Duty cycle on this 260?
The Landis site is kinda vague, and I want to be sure we got it right.
The car runs better now, but has hesitation when you snap open the throttle... almost feels like a misfire.
Maybe we can post a video of the throttle plate when it does this....

We are gonna change the plugleads and cap/rotor , idle and vac pipes arrived too, so by the weekend we will have all the normal stuff done.

i remain corrected, the egr system with the air pump and egr valve started in 1991 which is the year of my 190E 2.6 which is interesting. Emissions until 89 was controlled by lambda.

Download Checking on ratio.pdf from FileFactory.com

There is a lot of misleading information in this thread.

An '87 does not have an EGR system.

This car has high HC and NOx.

High NOx is not caused by richness. It is caused by a lean mixture (unlikely if the system is working properly), too high compression, or a bad catalytic converter.

My guess is cylinder deposits causing high compression. Do an Italian tune-up (full throttle on the highway to maximum revs), or try the "emission-passing magic deposit remover" solutions from the auto store. or pull the head and scrape them off.

High HC can be caused by a rich mixture (unlikely if the system is working), misfiring, a vacuum leak that affects only some cylinders (so that the system tries to compensate and makes the others too rich), or unburnt oil.

My guess is misfiring.

Tackle the basics: new plugs, new plug wires, clean up the cap and rotor, make sure that the on-off ratio is oscillating around about 50% (some say a couple of % under). Make sure that your O2 sensor is ok (there is a checking procedure in the Mercedes CD manual under CIS-E)nand replace it if you are not sure. We are now up to $200, cheaper than going to a repair shop. If your on-off ratio is not oscillating, then it is indicating a fault code, and you had better have a look at the CD manual.

Look in the DIY section for Steve Brotherton's article on evaluating engine controls. It is very thorough on the on-off ratio and EHA.

Your meter does not indicate exactly 70%, because it is not an accurate meter. My Sears meter also is a little off. Don't worry about it; just make a mental adjustment.

Our 190e 2.6 passed aircare yesterday with flying colours, at 370,000 km (about 230,000 miles). It recently needed a new fuel distributor. It had a recent O2 sensor. It has old plugs, cleaned, filed and gapped. It has the original catalytic converters. I just broke down (against my better judgement) and put in a new cap and rotor, replacing the originals. Otherwise, just the basics. Yours has much less miles on it, and is unlikely to have any fuel injection components worn out. Just the basics.

Andrew
1898 190e 2.6

already mentioned the info on what causes NOx. The car failed for NOx and hydrocarbons true but taking care of one will take care of the other.
The best and only way to clean carbon depoists from a motor is to use atf. All the other stuff on the market will screw up bearings etc and you cant get it out of the engines 100% completely. the m103 is a high compression motor since it require premium fuel only. Can carbon depoists be adding to the already high compression sure.

his lambda ratio is over 50% which explains the high HC's. Doing a tune up would help the problem but may not solve problem. Adjust the lambda ratio and pull a spark plug to see how its running.

i understand the Oxy sensor is a thermo couple, that is it produces voltage when reach working temp.
i read from wikipedia on these gizmos.

200 mv = engine running lean so ECU will dump more gas in.

450 mv is ideal as normal function.

800mv = over rich so ECU cuts fuel.

ANother trick if needed to pass Emission tests, one can parallel a small 1.5v battery and a rheostat ( a small volume control ) to adjust the voltage. U have to make sure the polarity or else can be very costly.

There are 3 wires, a common ground and a positive power for the heater to the O2 sensor.

I was told Merc run the wire thru the right side of trans tunnel to the pass side foot well. If u pull the carpet, a piece of plastic board almost 60 degrees for foot rest, use a 10 mm socket to remove the panel. The ECU should be below it. See if the wires feed thru.

Imight try to find a used O2 sensor, there's one in my area wanted 40 and had passed emission few mths ago.

let us know what happened.
cheers