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djimmy31 12-14-2004 09:17 AM

Benz decided to take a crap on me this morning
Hey hey,

Anyone care to take a stab at this,please?
:pukeface: The 88 300e decided it would take a crap this morning I guess. I do the same thing every morning, I go out about 10 minute-15 minutes before I leave for work and start the car. Well this morning is the 1st cold morning we have had below 30 degrees. I start it as usual no problem. It idles fine in gear. If I rev it though it stumbles some. Come back out and hop in the car and it starts stumbling really bad even died. Started back up but had to crank it for 10 seconds before it fired up. I tried again and it stumbled, spit, and sputtered. If I let off the gas it would kind of go back to normal but if I gave it gas it started back stumbling. Did that around the block barely running, brought it home and drove the explorer to work. The temp when I got in the car was right at 80c. So it was warmed up it seems. Any clues on where to start when I get home??????? Never has done this before.


Pete Geither 12-14-2004 10:49 AM

My first guess would be fuel pump. My TE did the same thing twice. You guessed it, it has 2 fuel pumps and one went bad within a week of the first failure. :eek:

djimmy31 12-14-2004 10:58 AM

:pukeface: not what I wanted to hear. Is there a way to test the pump? I assume test to make sure it's getting power and then the fuel pressure?

Jackd 12-14-2004 12:32 PM

Could also be a clogged fuel filter.
Also, prolonged idle periods (as you do....10 to 15 minutes of idling a cold engine) could promote spark plug fouling and cause/contribute to the problem you are describing.

djimmy31 12-14-2004 03:01 PM

Thanks for the replies. I replace the fuel filter as I have one at home new in the box. I wouldn't think it was bad as it was replaced about 25,000 miles ago. Although not sure how long they last? The car has 145,000 miles on it now and has never done anything like today.

y2kimmel 12-14-2004 03:16 PM

Gas Line Freeze?
You said it was below 30 degrees - could there be some frozen water in the system causing problems?

Maybe a can of dry gas could be the first step. I always try the cheap fixes before throwing parts at a problem.

djimmy31 12-14-2004 03:49 PM

sorry I meant 30 degrees, not 30 below 0.

:eek: 30 below 0 means I don't leave the house lol

d2bernhard 12-14-2004 04:34 PM

OVP? FP Relay?

djimmy31 12-14-2004 06:21 PM

I am going to check the ovp right now. I hope it's not the FPR as it was replaced about 5000 miles ago. Little update. I get home and try to start the car and it would not start. Cranked several times and it just turned over. About 30 minutes later I am getting ready to push it in the garage but decide to give it one more try and it starts. I pull it in the garage and the girlfriend says "geez it smells like gas big time". I guess I will check the ovp and then the fuel pump.

mike690003 12-14-2004 06:41 PM

I replaced my fuel pump relay, and 1 month later it went out again. Sometimes, but rarely, parts come from the factory defective. It might be the fuel filter, or maybe moisture found its way into your gas tank.

psfred 12-14-2004 07:45 PM

Strong smell of gasoline is either defective ignition or a leak, check both.

Most important, pull the cap and check condition of rotor, they are known to break. It's probably the original, and burned beyond recognition as well.

Ditto for plug wires and plugs.


djimmy31 12-14-2004 08:56 PM

Hey Peter,

I will check that out tomorrow. Is there 3 hex screws that hold the distrubuter cap on?

djimmy31 12-15-2004 07:33 PM

Little help update. I checked and there is a spark going to all of the plugs. Also changed the fuel filter since I had a new one laying around. Check the plug and rotor and cleaned them up alittle. They didn't look bad but not brand new either. I pulled a couple of plugs and they also look alright. Today when I tried to start the car when cold it was very hard to start. Had to give it some gas. Also even after being warmed up it didn't run good.

Heres the part that I hope will ring some bells. If I rev the car slowly up to around 3500 rpm it seems alright. If I mash the pedal kind of fast it spits and sputters. Same when in drive. If I slowly get it up to 30 it's fine but if I put a quick load or go up a hill it acts up. I was thinking of replacing all the plugs since they are cheap but I don't want to do much more throwing parts as most everything else is expensive

Any thoughts???????????????? :bulb:

psfred 12-16-2004 01:37 AM

Idle control valve hoses, it's under the air filter housing. Chances are they are rock hard and leaking, so you have air (and dirt) entering the intake that is not being measured by the air flow meter. This results in a lean condition beyond the ability of the feedback system to adjust, so it runs rough and stalls under load.

The cure is new hoses (one is a real PITA to install), and to check for any other leaking vacuum lines.

You should also check the O2 sensor for proper operation, if it's bad, the mixture won't be right.

Check to make sure it's not running way rich, too (black plugs). This is, alas, a sign of a dead fuel distributor ($$$$$$).


Tigger55b 12-16-2004 07:24 AM

Same-o Same-o!
Darn, My 90 300E started this same identical crap Monday. Same symptoms exactley! I changed the plugs. Plug wires are almost new. Checked and cleaned the Dist cap and rotor (they are only one month old). Changed the fuel pressure regulator. Replaced the OVP. I guess the fuel filter is next. But I really suspect the fuel pumps.

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:

djimmy31 01-03-2005 08:48 AM


I will try all the things listed and see what I come up with. The shop I took the car too was suppose to be a great benz shop in Louisville. It seems I can't find a good mb shop here in louisville. I honestly believe you guys are smarter than some of the shops. After a week and $110.00 later I am told alot of maybes and my car is old and tired. lol :rolleyes:

Just a run down of a few items
1. Car loses about 1 quart of oil every 3000 miles. Some leaks at front seal by dist cap.

2. Plugs were replaced 2 weeks ago. Tech said drenched in oil.

3. Brand new Bosch plug wires

4. Will check fuel stuff Juan talked about.

5. How can I test the O2 sensor?

6. How can I test the cat, or can I?

7. Will the valve guides cause the terrible bogging?

8. How can I test the coolant sensor?

Tigger55b 01-03-2005 01:16 PM

Man,, I have read all this stuff and some of what the Mechanic told you does not make sense. If you changed the plugs and they looked ok, how the heck did they get oil soaked. I have by-passed my cold start switch (again), and I can start the car fairly well. Except that it will stumble until it reaches operating temp. Oh yes, I have replaced:

Plug wires
Distributer cap
Engine temperature switch
Fuel pressure regulator
Fuel Filter
Tranmission modulator

There does not seem to be any vacume leaks.

This did not give me any warning when the symptoms started. It started fine, I went for a drive, shut it down and went to start again about 10 minutes later and it started this crap.

Couls it be the "Brain"?

djimmy31 01-03-2005 07:41 PM

Man Tigger I hope one of us finally figures this thing out.

I picked the car up today and spoke with them for awhile. They are saying now that the throttle position switch is bad. Also they are saying that the cat is bad. The guy recommended a place that would replace the cat for $300.00 bucks. I guess a unversal one.

I really don't want to spend $300.00 for something they may fix the problem. Would it hurt it cut it out or unbolt the cat and drive it around for a few miles and see what happens???

Tigger55b 01-04-2005 07:00 AM

It will be noisy, but it will not hurt anything.

djimmy31 01-05-2005 08:38 PM

Well I cut the cat off and the whole exhaust fell hahah. Anyway the car is loud and sounds like an old farm tractor.

I took it for a spin and it did run better but it still has the cutting out problem. I am ording the throttle microswitch tomorrow and will see what happens. If that doesn't work I might try the coil.


osjohn1 01-06-2005 09:45 PM

Sputtering Update?
Hello guys, I have been reading this thread on the sputtering problems with both cars and all of sudden the thread ends without any clear solution. So will someone please update on what was done to fix the problem. I am tracking down a similar problem in a 1990 300 E and I would love to follow some of the suggested approaches without having to waste funds on replacing good parts. Thanks.

djimmy31 01-07-2005 07:47 AM


Originally Posted by osjohn1
Hello guys, I have been reading this thread on the sputtering problems with both cars and all of sudden the thread ends without any clear solution. So will someone please update on what was done to fix the problem. I am tracking down a similar problem in a 1990 300 E and I would love to follow some of the suggested approaches without having to waste funds on replacing good parts. Thanks.

I wish my car was fixed John. As of right now it's still doing the same darn thing. I will surely being posted soon as this thing is fixed, or I might be posting a picture of it getting crushed at a junkyard lol.

JUAN 01-08-2005 12:02 AM

Hi fellows,
I was hoping to find a post that an answer had been found. I don't know if this is allowed but here it goes. I subscribe to a magazine that deals with old cars. There is this column this guy writes on troubleshooting. He wrote this book called "Tuning Up Autos and Trucks, A Guidebook of Solutions for Testing, Evaluating, and Analyzing Computer Controlled Vehicles". The book cost 60 bucks. I'm planning on buying it, I figure it would be a good read and it might help in the troubleshooting area. He helps people troubleshoot their cars in the help column. His answers and ideas are sensible and he seems to know what he is talking about. In these days were mechanics are hard to find that are interested in troubleshooting problems instead of just shotgunning parts, this might help you out. The phone number to order the book is 916-685-4527 and the email is Good luck and keep posting specially if you find the answer.

Tigger55b 01-10-2005 08:01 AM

Taking a break!
I have not found the problem/problems yet. I am now driving my trusty little 94 Toyota Tercel (It never stops). Its not as luxurious as the 300E, But its gets me where I want to go. I will psot when I get back into trouble shooting the 300E.

a2aa 01-21-2005 04:33 PM

clean the throttle body/ plate with rag saturated with good cleaning solvent

Tigger55b 03-14-2005 07:18 AM

OK!,, I finnaly broke down and decide to invest in the fuel pumps. Walla!! all fixed! Everything is fine now. Who woulda thunkit? Afer all the guessing and tinkering it came down to the obvious. CHANGE THE PUMPS!

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