83 500 SEC
Enrique changed the oil & got the AC super cold.
I guess he'll be seeing me again real soon.

I'm not sure where to start & hope Enrique can figure it out.

Hi Guys, I'm back!


2009 Failed Smog



Passed 2009 Smog after new O2 senser (NO levele went down)

So hoping a new O2 will work but do they only last 1200 miles?

2009 Pass Smog:



History:
O2 sensor was changed in 2009 with 1200 m ileage.
New SP wires Dist cap & rotor (1500 miles). New fuel acummulator 2008
Air Filter has 1500 miles

2011 Smog Pass



Only 700 miles in last 2 years since 2011 smog pass

2013 Smog Fail



She's basically failing on the NO
Max 15mph is 1074 mease 1532
Max 25mph is 904 meas 1372

& tad high 20 points over max on HC in the 15mph

Could be a vacumn leak?
EGR valve?

I ran it 30 miles before taking it in so it should have been at operating temp.



Anyone have any advise?

She passed fine 2 years ago & there have been no engine adjustments



Thanks

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83 500 SEC Euro 198K

So now will have a incomplete reg but no extra fees?

Tips point to EGR valve.

Enrique can't see me til Monday & reg is expired well renewed incomplete/



Pins & needles

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83 500 SEC Euro 198K

HC is high, you likely have an ignition problem.

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CENSORED due to not family friendly words

Enrique said he'd start w testing vacuums?
Some are old where I could not access but did change every rubber connections I could get my hands on.

It doesn't have the electronic idle control valve
Someone put a air vacum one.

Its harder to start hot & will idle a bit rough on hot starts.
Still its runnung very strong & smooth

This smog guy was not very good
He couldn't even open the good latches after I showed him how
Kept pulling & tugging everywhere til I had to scream & run over to make sure he didn't bend something.



It was a late last minute end of day referral as my reg guy lost his star & was awaiting inspection.

Arrgh

I have limited funds so I am sending in that Ca help fix a car for smog reimbursement.
Still if its not too $ I'd rather Enrique do it & get it over.

I could trying playing w the EGR v but would I need to get a new gasket?
From what I have seen these things get really clogged.

Maybe engine was too hot?

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83 500 SEC Euro 198K

Running weird since smog.
Right after I got home it stalled getting into a parking place & today it stalled on sepulveda as I was changing lanes.
Its also running lumpy on idle.
New things since that darn guy played with it.
I don't know what he could have touched
but it needs something & it seems to be at hard turn it strains.

Idles around 600 in drive.

I have the idle control with a yellow top that you turn with a screwdriver.
Can't remember which is higher or lower.

Rubber to EGR is stiff & turns.
I never could change that as I never coould get one end off.
Could be leaking.

Its also super low so sometimes pipes rub on my steep driveway.
My luck I have to have a real tall ramp at my apartment.

Darn, I really wanted to start using her but its hard getting it in & out of the driveway.
Just so many things

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83 500 SEC Euro 198K

Sounds like your smog guy may have accidentally dislodged a vacuum hose or something under the hood. Get in there and look. Post pics if you can. That will get you back to your original problem of not passing smog. The high NO points to an EGR problem. Maybe not opening, not opening enough, or the passages are too clogged. All three are fairly likely on a 30 year old car.

The high HC leads me to believe your fuel mixture is too rich. I'm not very familiar with the type of fuel injection your car has, but there are several things generally that can go wrong to cause that issue. Aging O2 sensors will do it, but you have a newish one, so it's unlikely to be that. MAP and/or MAF sensor failing could also be a culprit, as could a bad coolant temp sensor telling the computer to run cold fuel enrichment after the engine is warm. Pull codes if you can. On an OBDII system, this would be stupid easy.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Car stalled pulling into Enriques shop at hard turn.
This is the 3rd time.
Enrique advanced the idle.

Enrique checked the EGR valve & said it was good.
I guess the line could still be leaking somewhere?
He didn't want to look any further pointing out it could get pricey esp if we get into cat territory.

What about a 4 yo barely used Oxygen senser?
He just didn't want me to incur costs

He suggested I get some sort of waiver...a referee?
My car is a euro so grey market & could qualify.

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83 500 SEC Euro 198K

I'll bet your cat is toast. Your really close to the limit in all areas including the fail areas. I would almost bet $$$. If it were me i would just get an aftermarket one or two and go with it. If you can find someone with a exhaust gas analyzer that would help a lot. you can probe in the O2 sensor hole to see if the cat is functioning. I have one but I'm kind of far. I used it for dialing in the 280sl.

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Chris
84 280sl
82 300d euro

is well. You have to make sure everything is in working order. Tune up, plugs, rotor, wires. Check all vacuum hoses. It could be a combination of things. Also if the Cat. is coated with stuff on the inside sometimes running for a long time at high revolutions can clean it out. You would want to drive above 2500 RPM's as long as possible to heat it up and burn the stuff out.

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Chris
84 280sl
82 300d euro

At 192k miles, engine blow-by is probably the culprit.

I know cars. I know late model Mercedes vehicles, so Im guessing here...

1) 1983 with 190k miles - A lot of city miles - very worn car... - a lot of start stops...- if less then 5mile trips are made, it is hard on the CATS. The car has to come upto temperature-This is important in cold weather...

2) The engine blow-by is greater than a 190k mile highway driven car.

I'm assuming if my 96 S320 has a vacuum controlled EGR. Your 500SEC probably has a vacuumed controlled EGR too. If it is vacuum, you can test the whole Exhaust Gas Recirculation (EGR) very easily... This method works on any make or model with vacuum controlled EGR valve.

1) disconnect the vacuum line at the EGR, and plug it with a pen cap

2) Attach several feet of vacuum line to the EGR valve(make sure the line fits snug on the nipple of the egr)

3) With the engine off, suck on the attached vacuum line, and you should feel and hear the EGR vacuum diaphragm actuate

4) Now with the engine on, and idling. If you suck on the line, the engine should slow down, hesitate, and possibly stall. If it does that, the WHOLE EGR system is WORKING!!
If it does not slow down, the EGR passages could be plugged. On most cars a steel pipe taps into the exhaust and channels it to the EGR valve and then channels it to the intake manifold to mix with the fresh intake air. In about 90% to 80% of cases the EGR passages plug up with carbon, next the vacuum to control the EGR valve is not present in about 10% of cases, and lastly the EGR valve fails(now the EGR could be gummed up to with carbon). The Mercedes cars are weird when it comes to the EGR passages. Some engines have the EGR steel pipe, and some have the passages through the engine block. If yours is on the engine block, it is hard to near impossible to unclog. If you have the metal pipe, the passages can be cleaned with a coat hanger on a cordless drill, so it tears-up the carbon, but does not damage the steel pipe- Very much like a kitchen drain clean-out is done.

5) now test the plugged vacuum line. Take the pen cap off. Put your finger on the vacuum line. You should feel little to no vacuum while idling, but while you rapidly accelerate to about 1200rpm and let go the throttle. The vacuum will be greater as the rpms rapidly drop. You may get vacuum when you rapidly accelerate. If this works, the EGR vacuum control is working okay. If this NOT present, you better chase this down as this may be plugged, or you may have a broken vacuum line

The CATS can be tested with a Infrared temperature gun, but this test can only help you with Hydrocarbons numbers. The NOx's are mostly fixed on the engine side.

1) Measure the inlet pipe going into the CAT(s) at about 6" to 10" before each CAT.

2) Measure the temperature on the cat, but measure it from the CAT not the heat shield.

3) Throttle your car to 1500rpm, and hold it for a minute. Measure the CAT's. What you are looking to see in temperature is the the actual cat should be several hundred degrees hotter than the inlet pipe. You will need a helper to hold the throttle. If you want to test this technique. Do a the test on any late model car to test the CAT temperature differential test. If the temperature is the same, than your CATs are probably toast

A thing I would do before the CAT temperature test, or your next smog. I would clean your plugs with some fine sandpaper, yet providing they are not wet.. Next I would clean-up cap and rotor with sandpaper/file/ worn dremel bit on a Dremel. Borrow a dremel, or buy the cheapy $9.00 dollar one from Harbor Freight to clean-up the cap and rotor. Use the pink stones. Be careful when working the rotary tool as it can grind down your cap and rotor. You want the contact points on the cap and rotor to be shinny-It will improve the efficiency of your ignition components.

In some cities, one can find these gas stations that sell about 110 Octane racing gas. I remember when I lived in the Los Angeles area. I saw about six of them.

I'd even get some of the chemicals that help you pass the SMOG tests.

Hope this helps you as these are cheap fixes and test to help you. As the best thing to do, replace the CATS, but that is going to cost you.

Best of luck,

Martin



Rotary Tool Kit - 80 Piece Set

Thanks, all good points.
History of this car is it was run minimally say 200 miles per year when I got it in 2007.
I have been almost as bad running it short distance local.
I have used techron gas adative but not recently.
I did run it 30 miles before the test at 40 to 50 mph.
I'm not sure what speed it runs at 2500rpm.
I guess its worth a shot to try to revive the cat.
Could I run it at 2500 in park?

Wires, plugs rotor & distributor cap have less than 2000 miles. Would this need attention?
I tried to change all the black rubbers I could get access to.
There were some in the back.

My car does not have the electronic idle.
Its manual but not sure how that affects it.

I have applied for up to $500 worth of reimbursement for emisson related repairs. It seems best to get it fixed if I can get the money back.
These repairs have to be at state approved shops

I think I should take this back to my orig euro thread as I want to load some diagrams & pics of the vacumn hook ups.
I still may have something wrong.

My 1st inquiry is that this hos out of the manifolds is? It goes no where.
Asked Enrique 2x & have no answer.
I guess its before the cat so it doesn't seem that it would effect emmisions but I want to hook up things right.




Thansk for the details of the egr. Its possible some line or vac is loose/ cracked so still could be egr related with a good egr?
My mechanic said the egr is working so does that mean it does what its supposed to?
EGR is vacumn & think it has 2 metal tubes on either end. Its above the valve covers
I would hope Enrique would check it properly.
I'm still not sure of direction of airflow or operation of EGR but it can't hurt to try & check for buildup

This is a diagram but hard to follow



I was checking relays & red top OCR wiggles in its slot... possible intermittent connection?

Thanks a bunch!

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83 500 SEC Euro 198K

When you start cold how does it run? Do you get a fast idle for a minute or so while it warms up? It should slow to normal within a few minutes. Does it run smooth then act roughly after it is warm? If so then you have a lean fuel condition. That would point to a vacuum leak. I would be sure all vacuum hoses are good before even looking at the Cat.
It looks like previous years you were very close to a fail. One you were at the limit exactly on HC. That leads me to believe this issue has been going on for a while. You just noticed now because it got worse. Driving it that way would do the Cat in. It is possible your Cat has been on the way out for a while causing the high readings. It is also possible that driving the car with it not running well killed the Cat. If it is the latter you need to address both issues. If you get a new cat and it still runs funny it wont last long.
It looks to me like you have a lean mixture. Low CO and high HC points to a lean fuel ratio.
That metal hose is a heat riser. It should connect to the bottom of the air cleaner. It looks broken. That wont cause emission trouble. Its part of the warmup cycle and opens a valve on the air cleaner for fresh air I believe. See if you can find where it goes under the air cleaner. You can get a new riser easily from a hardware store. It looks like foil right. My old Nissan had its heat riser off for years. I really doubt that is your issue, but it could cause a fail for the visual inspection part of the smog test.

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Chris
84 280sl
82 300d euro

You are a lucky man if you can pass visual SMOG test with the metal pipe sticking out...

I'll just reply in order of your email.

The things you've done are fine-gas-30mile drive is fine, but I was told on my late model computer controlled cars to drive them 50 to 100miles. I think you should be okay. Also, you want to go to the smog test right away. Non of this sitting around for 15min to 30min before the actual test.
I'm sure 2500 is around 70 to 80mph with a transmission with overdrive, so on non overdrive transmission it will be around 50 to 60mph. With Mercedes Cars, the overdrive transmission did not arrive until the 722.5 transmission. Your transmission 722.3 or earlier unit. Once your CATS are gone. They are gone. On the RPM, you can run that RPM in park.

The cap and rotor. I would inspect it, and clean them with fine sand paper. Put dielectric grease on the boots of the spark plug wires. I HOPE YOU ARE DOING THE DIY ON THIS CAR BECAUSE PAYING FOR ALL SERVICES ON THESE CARS IS REALLY A LOSING PROPOSITION....

About the idle, it does not really matter, but like all cars of the eight's had a idle damper by a cushion diaphragm, or one controlled by vacuum that has step graduations.

Inspect your vacuum lines and soft rubber unions as they get soggy soft like a marsh mellow if my 1996 had some. YOUR 1983 WILL DEFINITELY HAVE SOME BAD ONES.

The metal pipes, no clue... My guess is the EGR pipe, but it's location is odd. The pipe could be the heat riser from the exhaust to aid in the warming-up of the car. The pipe is generally about three to four inches in diameter, and it feeds into the air cleaner assembly.

The other possibility's:

a) is the fresh air injection into the CATs to aid in emissions burning in the mornings-All modern cars have a electric pump that operates and has a valve to let the air pass. I do not know if such a system was uses in the 80's(definitely not on domestic cars of the time).

b) crankcase gases pipe, but generally these gases are taken from the valve cover threw a one-way check valve called a PVC on the valve cover.

c) the pipe is too wide for it to be charcoal gases recirculation ...

Do the EGR tests your self to qualify the EGR gas system, and to test the vacuum control to the EGR.

Best of luck,

Martin

You probably have one of these on your car. It is not mercedes original, but has to do with getting it BAR smog certified. There should be 2 wires going to the metering valve close to the K-jet fuel distributor. That valve should be making an intermittent buzzing noise. Also be sure all wires are properly connected to the little black box. It should be behind the passenger kick panel.
There are also tests that can be performed on the lambda system but Its beyond my knowledge. My Lambda has adjustments. They are all different. you may try opening the box but your in territory for an exhaust gas analyzer.

I would focus on getting it running smoothly then look over the Cat. I dont think you need to check the EGR anymore as long as you trust your mech. That system is a cinch to check. if you have vacuum issues in that area the EGR would not operate. I doubt he got it wrong.
Did you check all the vacuum hoses going to the dash controls, and the transmission. How does the transmission shift. That could be an indicator. Do you hear any hissing noises anywhere. You can block off all of those areas to see if you get a change in performance.

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Chris
84 280sl
82 300d euro

Transmission shifts fine.
There's alot to digest but it will be nice to get her in better form.
My mechanic is Enrique of MB Motors.
He's helped get this poor car back on the road & he is very conservative not wanting me to spend too much $.

As far as cat cleaning can I run it in park? Would it hurt the engine to run it for an hour or so?
I'd do it if it could burn off residue in cat. The cat doesn't rattle.
When the cat failed in the
Volvo it would rattle under the car. I guess my driving habits is killing my Volvo too.

I work at home & use the car for local arrands or to shop m ostly.

I'm only a novice mechanic but I did put on a new distriburtor cap & rotor.
The old rotor tip was burned with cracking.
I guess I could open it up & check what a few years & under 1800 miles has done.

I'm going to have to refer to the original post that has many pics & details all the info on this car.

My 500 SEC Euro thread:


http://www.peachparts.com/shopforum/tech-help/197661-upgrade-83-mer-500-sec-88-volvo-gle-75.html#post3163634



I'm pretty sure there is no hole for that aluminum hose under the aircleaner or the black inlet tubing. The hose is only about 1 inch in diam.

The car is a euro so had to be converted so maybe this is left over from that.

Carcoal cannister is on other side of engine

I guess I can bend the hose so that it faces down so not to be so obvious.

I'm not sure how I would check wires leading into fuse box but I did observe the OCR or is it OVR relay will rock if you move it. ????
The OVR was replaced as were all the soft rubber connections that I had access to.
I don't know how to check vacumn or with what equipment is needed.

I could try to listen for hissing but haven't noticed any.

PCV ? not sure

Car used to be very hard to start when hot.
Enrique changed the accumlator & now it take a few cranks but starts hot. It does seem to idle lumpy when hot started.
Leakin of fuel porobably from old injectors...etc.

Lean mixture was dilaed in by a smog station in 2009 to get her to pass.
I was concerned to run her that way but Eneique suggested leaving it so that smog would be ok in 2 years.
It was stalling when AC was running so Enrique increased the idle
The idle is air controlled not electronic & there is a yellow plastic circle with a screwdriver slot that controls the air.

With AC running in drive she ran about 500 550 rpm.

Age of car & all of this is a handful to try to address.

I'm going to try to get through all these great suggestions]



Thanks

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83 500 SEC Euro 198K