1989 300E Intermittent start/run problem. - Page 2 - PeachParts Mercedes-Benz Forum

A264172 · #16 10-16-2006, 02:56 PM

http://www.peachparts.com/shopforum/showthread.php?t=143941

gmercoleza · #17 10-16-2006, 03:14 PM

Quote:

Originally Posted by A264172

http://www.peachparts.com/shopforum/showthread.php?t=143941

Thanks - learn something new every day. That's pretty weird. I fear the day I end up with one of those unexplainable intermittent problems. To think you checked the O2 previously and it checked out good!

BTW, I will be coming up on O2 sensor replacement soon in my 300E. 150K miles on the original seems like it's on borrowed time. Anything I should know about doing the Ford Mustang sensor? That's what I planned on using...

A264172 · #18 10-16-2006, 03:25 PM

Quote:

Originally Posted by gmercoleza

...BTW, I will be coming up on O2 sensor replacement soon in my 300E. 150K miles on the original seems like it's on borrowed time. Anything I should know about doing the Ford Mustang sensor? That's what I planned on using...

These solder tips are a little usefull...
http://elitecaraudio.com/tips/car_audio/soldering1.shtml
...but over all it's a pretty basic opperation. I use an O2 socket and flex socket wrench with a breaker bar to get the sensor out... comes out pretty easy that way.

gmercoleza · #19 10-16-2006, 03:39 PM

Thanks!

Moneypit SEL · #20 10-16-2006, 04:04 PM

Quote:

Originally Posted by A264172

http://www.peachparts.com/shopforum/showthread.php?t=143941

Fair enough. I wish I'd had my 'scope on the O2 signal to see what it was doing. The only thing that makes any sense to me is if the O2 heater was shorting to the O2 signal. And I still don't see how it could be intermitent.

A264172 · #21 10-16-2006, 04:23 PM

Quote:

Originally Posted by Moneypit SEL

Fair enough. I wish I'd had my 'scope on the O2 signal to see what it was doing. The only thing that makes any sense to me is if the O2 heater was shorting to the O2 signal. And I still don't see how it could be intermitent.

You wish? I wish you had your scope on it even more...

Felt like I was trying to catch a mouse wearing a blindfold on that one...

I might be able to dig it up and send it to you if you want to play around with the sensor that did the acting up.

Moneypit SEL · #22 10-16-2006, 08:15 PM

Quote:

Originally Posted by A264172

You wish? I wish you had your scope on it even more...

Felt like I was trying to catch a mouse wearing a blindfold on that one...

I might be able to dig it up and send it to you if you want to play around with the sensor that did the acting up.

Naw...that sounds too much like work.

cjlipps · #23 10-25-2006, 12:50 AM

Too busy to work on car but attempted to start it today after it has sat for a couple of weeks untouched. Nothing...... Cranked but nary a burble from the engine. I should have some time this weekend to check it over a bit but in the meantime, does this latest symptom mean anything definitive? Previously it started every time I've tried and after getting progressively worse it won't start at all. My first shot is going to be at the fuel pump relay and if that doesn't prove fruitful, it's off to ignition world. Any thoughts would be appreciated. BTW, what is an EHA? I followed a suggested thread and couldn't determine what it was.
Thanks to all. As a side note, my '90 300E is running great thanks to info from this thread. The last tank was 26.3 mpg and it's never below 24. Just one climate control issue to sort out (not too bothersome in the winter) and the car will be near 100%.

cjlipps · #24 10-30-2006, 04:38 PM

After a few attempts to start the car, I removed the FPR and jumpered the two terminals (can't remember the numbers now, is it 30 and 87?) and nothing....So, removed the cap and rotor and believe I have found the problem. The rotor was contacting the cap and had chewed away part of the plastic around the cap terminals. In addition, the end of the rotor that sweeps past the cap terminals (sort of a rounded T-shaped end) had broken away from the metal strip that connects it to the center of the rotor. It was still anchored in place on the plastic of the rotor but it was free to pivot a bit and wasn't making good connection. (Can't post pix just yet - would love to) Odd thing is that when performing the old disconnected plug wire spark test, I had a good strong spark. At any rate, new parts are on the way and we'll go from there. Anyone ever see a rotor and cap hit each other before? The rotor carrier didn't seem to have walked endwise or anything that would cause this but the groove in the cap caused by the rotor was about 3/8'' past where the rotor tip should be running. Thoughts or ideas???
Thanks to all. Will post results later this week.

Johnhef · #25 10-30-2006, 05:09 PM

The only time I've seen that, the bolt head that holds the rotor bracket to the end of the cam had broken off and was letting it move freely. this was on a '93 190E 2.6

cjlipps · #26 10-31-2006, 12:43 PM

Thanks Johnhef, I'll check it out. The carrier wasn't obviously loose, I couldn't move it with my hand but I'll inspect it better. I'm also going to compare the new parts with the old ones on the outside chance the old ones were wrong.

the tenor man · #27 10-31-2006, 04:47 PM

I had a similar problem on a 1989 260E...Here's what it was (after over a year of screwing around)...the electrical connector for the twin fuel pumps...under the rear seat near the vacuum motor....

It was green with corrosion...I thought I could clean it up but instead I removed it and soldered the wires together....

The stalling and dying never happened again....but by the time I got all of the "quirks" solved, some dumbhead ran into the rear and totalled the car....my daughter got out without a scratch...

That's life,
The Tenor Man

cjlipps · #28 11-03-2006, 10:19 AM

Well, Johnhef hit it on the button. I wondered if that was the case when while reading his post I remembered that I had found a mystery allen bolt head in the bottom of the fan shroud. I looked into the hole in the rotor mount with a mirror and the bolt head was broken off and had allowed the rotor to migrate forward until contacting the cap. Problem is, I couldn't for the life of me remove the rotor carrier to attempt to remove the bolt and it took significant tapping to reseat it back where it should be. I installed the new parts and the car started immediately and ran fine. I will just have to somehow get the broken bolt extracted and a new one installed although, as difficult as the rotor carrier was to move, I'm comfortable with the thought that it will take quite some time to walk forward again. Mind you, this isn't a daily driver and won't be taken on any long trips. I'm just trying to decide if I can do an E-Z out and use an angle drill since there's not enough room for a conventional drill with the radiator and condenser in place.
Thanks for all the input. I'm sure I'll be needing more in the future.
Chuck.

Tims450SL · #29 08-26-2008, 04:16 AM

i guess i am removing cap and rotor tomorrow before buying a coil....what about the removal of the fan?> is everything a hassle?

Tims450SL · #30 08-27-2008, 05:50 PM

Replaced CPS and had the enrichment tweaked and car is ok now...