PeachParts Mercedes-Benz Forum

PeachParts Mercedes-Benz Forum (
-   Tech Help (
-   -   Benz decided to take a crap on me this morning (

djimmy31 12-16-2004 07:30 AM

Ok today I will check the idle control valve hoses. The better be fine though as the stealership charged me for changing them lol. Maybe one just slipped off some how, doubt I could get that lucky. The 2 plugs I pulled were not black had some wear but not black. Could be an O2 sensor has am not sure when or if it's ever been changed. How do you test it? Please don't let it be the fuel pumps, thats 400 bucks. :pukeface:

Thanks for all the help guys

Hopefully me and tigger can get these old cars fixed and back on the road.

Tigger55b 12-16-2004 08:04 AM

Mine went bad Monday. I started it and it ran fine. I went to Home Depot and picked up a few things and when I came out it would not start. Just cranked and cranked. I was just ready to call a tow when I decided to crack a injector line to see if it was getting fuel. Fuel was under pressure so I ruled that out. However, when I tried to crank it again it sputtered and started to act as if it was flooded. or out of gas. I knew it had gas so I kept trying. it finnaly started and sputtered for about a minut before it smoothed out. It then drove home with no problem. At home I shut it down and tried to start it again. Same problem. But it did start sooner. Only now, when I drove it, it did not want to rev quickly. It would try to stall and sputter when I pushed the pedal down quickly. I will also check those hoses today. I also have no idea how to check the O2 sensor.

djimmy31 12-16-2004 09:19 AM

hopefully one of us finds the solution as I bet it will fix us both.

djimmy31 12-16-2004 09:34 PM

Well I made some good progress and thought I had solved the problem but it's still there all though not as bad. I pulled all 6 plugs out and changed them. The all looked about the same. They had platinum plugs in there and I replaced them with the standard copper core bosch ones. Car is now very driveable accept for it still seems to have a stumble every now and then. Maybe I should replace the wires as well. Seems alright but sometimes it would stutter and then take off.

Any other suggestions guys?????????????????

djimmy31 12-18-2004 07:38 PM

Hey guys,

The spark plugs helped alot as the car is driveable. I am at a loss though as it's still hard to start when cold and still stumbles. I will probably replace the plug wires tomorrow. Is there anything I can test on the coil or like the x11 to see where a break down might be??????? I have the sears multimeter that everyone talks about on here.

Thanks :sun_smile :rolleyes: :cool: :D

psfred 12-19-2004 10:02 AM

Hard to start cold and rough running until warm means the cold start valve is suspect, it's not getting cold enrichment, or you have a vacuum leak.

I vote for the vac leak.

Check, in this order:

Main vac line to booster (loose connection on manifold)

Idle control valve hoses (if hard, replace)

Charcoal purge line

small vac lines to transmission modulator, ACC, temp switchover sensors, etc.

Another possiblity is the boot between the intake and fuel distributor.

It cannot be a huge leak, as the feedback system can compensate after it's warm. Big throttle lag sometimes?


jp928 12-20-2004 09:57 PM

I have seen this "revs come up if open throttle gently, but stumble if jump on throttle" scene when distributor advance mechanism is frozen - if you have this type of distributor witch mechanical advance stuff.

djimmy31 12-30-2004 10:00 AM

Well I am now sick to my stomach and not sure what to do. I just spoke with the mercedes shop that has the car and the response was not good. Guy said "Throttle switch needs to be replaced, the plugs are fouled soaked with oil, #6 cylender is not getting any spark, and the cat may or may not be clogged. It's just old and tired."

THAT SUCKS...... I just replaced the plugs 20 miles ago, the car burns about 1 quart per 3000 miles and does not smoke or anything. I am not sure where to go now, maybe to the junk yard lol.

I am thinking about replacing the throttle switch and gutting the cat. See what happens.

Car only has 140,000 on it. Is it really time to retire it? I know I don't want to dump a bunch more money on it.

psfred 12-31-2004 10:40 PM

Take it to a shop that REPAIRS cars and get an estimate. Sounds like that shop cannot diagnose a problem without a computer, and the ealier W124 posts codes differently. Likely you have an O2 sensor problem, or a fuel injection problem, and neither can be diagnosed via the on-board computer.

Dollar to a donut the plug wires are screwed up (the ends can come loose, etc) or there is something else wrong with the ignition.

Oily plugs mean you need new valve guide seals, and unfortunately, on this engine, if it is an early on (pre 88 or so), you are due for new valve guides, they wear badly on the early engines.

This isn't cheap (duh!), but much less than a new car.


psfred 12-31-2004 10:42 PM

My OM603 with 211,000 miles uses less than a quart in 7000 miles.

Oil consumption on the newer engines is negligable.

Oil leaks on Benz engines are fairly common, and can be cured if you want to spend the money. All European engines seem to leak a bit, for some reason. Some are MUCH worse than others.....


mike690003 01-01-2005 09:11 AM

Replacing the valve guides and stem seals is not a costly job ($200-$400) depending on where you have the work done. Replacing the stem seals and guides will stop the oil consumption, for about a year. Many say it is a temporary fix, but it will stop the consumption. The full valve job will cost about $1000-$1800. It is all according to what you want to do now.

psfred 01-01-2005 04:29 PM

Replacing seals is cheap, guide replacement requires removal of the head.


waybomb 01-01-2005 08:22 PM

In an earlier post you said the plugs didn't look all that bad. Did the car smoke at idle? If not, you probably do not need valve stem seals, and I've never heard of an engine with bad valve stem seals giving the problems you describe. For example, I had a 1987 Plymouth Grand Voyager with the dreaded 3.0 gas engine. At a stoplight, there would not be a mosquito within 50 feet of my van. Still started and ran fine, even though every valve stem seal was shot. I mean clouds of billowing blue smoke out the back at idle. My wife could'a killed me for hanging on to it as long as I did. She refused to be seen in it.
Anyway - I highly doubt valve stem seals is your problem.

A plugged cat will present problems at speed, not at starting. Think about it.

A throttle switch, well maybe. I'm sure somebody on this list can tell you how to test it.

Now i don't know what a 90 Benz has on it in terms of the FI system, but our 97 gave us all the problems you describe. Turned out to be the mass air flow sensor. Put it and the car was back to normal.

BTW - this forum helped me figure out what was wrong - THANKS!

JUAN 01-01-2005 09:55 PM

I had a car that would give me hard start problems when hot and smell of fuel. I know this is slightly different then what you described but this test is easy enough and it could be your problem. My took 3 mechanics not including the troubleshooting that I did a bunch of parts and about 500 bucks. The fix, the fuel pressure regulator was leaking sucking fuel from the vacuum line. Easy way to test it, is to hook up a hand vacuum pump that you can get at an auto parts store for about 20 bucks. Hook it up to the fuel pressure regulator where the vacuum line is with the engine off. Create a vacuum and see if it holds it. If is doesn't, the rubber diaphram in the fuel pressure regulator is bad. If this doesn't turn out to be the problem, you got yourself a nice little tool. Like others have posted, also check all your vacuum hoses and replace them. Good luck to you guys.

theairboy 01-01-2005 10:56 PM

Cold Starting
It never hurts to test the coolant temp. sensor. Its free to test and cheep to replace. If your car hasn't had one in a long time. I would just put one in. :bulb:

All times are GMT -4. The time now is 12:32 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website