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W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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Assuming that your meter does not filter out the actual O2 sensor voltage in a major way (meaning it really is slow to react to the O2 sensor going from very low voltage like 0.15V to aproximately 1.0V every 1-2 seconds I would say your lambda mixture control system is not functioning.

If this is the case, your issue around different behavior with the AC on/off compressor on/off might just be a secondary effect because the system is not responding like it should. This is just a wild guess on my part.

If I were you, I would first try to find out what is wrong with the O2 sensor system. I would like to help you there but honestly, with the exception of replacing the sensor twice in my car over the last 30 years / 200K miles, I have never had a non functioning O2 lambda control system. I suppose that is fortunate for me.

I'm hoping other members who have more experience with this can pitch in.

- Cheers!
 

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1992 W124 260E
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40 Posts
Discussion Starter #42
Ok, maybe my lambda control system is not functioning. I'll need to look further into this. And with the AC clutch not switching off like it used to 2 days ago, this is another thing to remedy.
Thanks dolucasi for your patience and help. This problem and both of the help I got here has been very helpful and useful that I have learned things about this car. Maybe some one will have other suggestions
 

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Premium Member
07 E350, 80 240D 4 speed, 90 300SE, 87 260E
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2,813 Posts
I don't see mention of the distributor cap on your original list. Did that get checked?
 

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1993 300CE Cabriolet (mine) ; 1994 E320 Wagon (wife's) ; 1990 Benz 300E 2.6 (son's)
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6,814 Posts
not reading this whole thread, but, our 260E used to stumble and stall intermittently when you gave it gas after stopping... it turned out to be air leaks around the injector seals, also a couple bad injectors. 6 new injectors with new seals and it runs like a new car.

before we got there, I'd replaced the ignition system, checked the duty cycle (was pretty unstable but more or less hovered mid range), replaced and verified the O2 sensor, replaced the EHA (twice, first used replacement was bad), replaced the air flow sensor potentiometer (was open circuit per my ohm meter), OVP relay, etc etc etc. new battery. ran endless tests going in circles.
 

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1992 W124 260E
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40 Posts
Discussion Starter #45
I don't see mention of the distributor cap on your original list. Did that get checked?
I only serviced the distributor cap and all 4 days ago after I saw a YouTube from WWMA who replaced his. When I replaced the spark plugs cables, it didn't register to me that THE distributor was just 3 screws away... I know that I should have serviced it when I first got the car. Excuses- I was busy then.

Thanks for reminding me.
 

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1992 W124 260E
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40 Posts
Discussion Starter #46
not reading this whole thread, but, our 260E used to stumble and stall intermittently when you gave it gas after stopping... it turned out to be air leaks around the injector seals, also a couple bad injectors. 6 new injectors with new seals and it runs like a new car.

before we got there, I'd replaced the ignition system, checked the duty cycle (was pretty unstable but more or less hovered mid range), replaced and verified the O2 sensor, replaced the EHA (twice, first used replacement was bad), replaced the air flow sensor potentiometer (was open circuit per my ohm meter), OVP relay, etc etc etc. new battery. ran endless tests going in circles.
Hmm, tuttebenne suggested that, too. I'll diy the smoke box soonest. The scary part is to actually find that the seals are leaking and finding new replacement parts for them. Any suggestions?

Thanks for sharing LeftCoastGeek
 

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1992 W124 260E
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40 Posts
Discussion Starter #47
BTW, the car is running smoother than before, for now... I am just driving short trips around my house. Hopefully, make longer trips as my confidence improves.. lol. The car was on the tow truck twice before. Hence, my apprehension
 

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Premium Member
'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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10,167 Posts
Injector seals are available and cheap. But I don't see them lasting more than 3-4yrs before they start to harden. I was surprised when I took them all out of my white, donor TE to put in my DD. They'd only been in actual use for about 4yrs. The ones in my DD were soft and supple....probably original or OE replacement back when it was last done, if ever.

Kevin
 

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W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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2,297 Posts
Hmmm, how did we jump from point A (well maybe B) to point Z in this thread?
Unless there was some serious abuse with this car (extreme weather, overheating engine, etc) why do we believe the car needs new injector seals all of a sudden and that is on top of the list.
I would at least do a smoke test before taking much action here.

The car has a non working lambda system. I would tackle that problem soon.

I do not see new injector seals hurting the cause, just not sure if it will solve Azamkb's specific issue.

A datapoint I have voiced in many threads. Same engine '89, ~200K miles. Never had issues with injector seals. Dealer must have replaced mine when they decided to donate me a free set of injectors....... Long story....
Sure every car is different, but just saying......

Happy Friday....
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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10,167 Posts
Not making any "jump" dolucasi, just making a comment on the currently available seals and longevity issues........nothing more.

Kevin
 

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W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
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2,297 Posts
Yeah, I hear you Kevin, it's just that sometimes people start replacing parts and get frustrated when the replacement does not fix their problem. Just wanted to warn the OP against false hope.....
 

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1992 W124 260E
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40 Posts
Discussion Starter #54
not reading this whole thread, but, our 260E used to stumble and stall intermittently when you gave it gas after stopping... it turned out to be air leaks around the injector seals, also a couple bad injectors. 6 new injectors with new seals and it runs like a new car.

before we got there, I'd replaced the ignition system, checked the duty cycle (was pretty unstable but more or less hovered mid range), replaced and verified the O2 sensor, replaced the EHA (twice, first used replacement was bad), replaced the air flow sensor potentiometer (was open circuit per my ohm meter), OVP relay, etc etc etc. new battery. ran endless tests going in circles.
Can we carry out test/s to determine that the car have bad injectors?
 

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W124
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Can we carry out test/s to determine that the car have bad injectors?
If you really mean injectors, yes, you pull them out and have them tested . If you really mean't testing for bad injector seals, yes, read post #20 again. I would use the propane test. Its quick and easy - maybe five minutes of your time to rule in or out the injector seals.

If I understand your descriptions of the problem it is essentially an engine that stalls after running a certain amount of time - sometimes in conjunction with turning on the A/C and sometimes on its own with no A/C on. The idle runs too high at times, and it is difficult if not impossible to start once it stalls. Is this an accurate description?
 

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1992 W124 260E
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40 Posts
Discussion Starter #56
As of 3 November, I haven't detected any shakes or stalling of the engine even though I ran the car at idle for almost an hour or while driving short distances.

I can't really pin point what I actually did to the car to be in this condition. Previously, I experienced this sort of situation, no shakes or stalling, but once I started driving longer distances, the shakes and stalling returned. Temperature was normal before it happened and all happened without the O2 sensor hooked up to the system. I'll take it for a longer drive in a couple of days and will report back.

Meanwhile, I have made a small smoke jar but haven't tested it yet.
 

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1995 e320ce. 1993 230 TE. 1987 Kit car with 260e running gear.
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636 Posts
Sounds like the distributor cap (and rotor arm and backing shield) to me.
Prone to condensation, and then tracking under load.
As Steve would say......A disposable service part.
 

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1992 W124 260E
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40 Posts
Discussion Starter #59
Sounds like the distributor cap (and rotor arm and backing shield) to me.
Prone to condensation, and then tracking under load.
As Steve would say......A disposable service part.
Funny that you said that. When I open the distributor cap, I did find condensation as I had to even wipe the water on the backing shield and cap and clean the rotor arm and 6 copper "thing" on the cap. The rotor arm, pin and 6 copper half "studs" still looked OK to me. So, I installed them back...

I'm now in maintenance mode rather than fixing mode since there's no longer the shakes and stalling. Until the car stalls again, thanks everyone for the priceless input and help.

Apart from the smoke test.
 

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I think Boyd nailed it. You should change the dust shield (insulator), cap, and rotor. They should be able to sustain moisture without the problems you experienced.
 
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