91 300e problems because of the rain? - Page 2 - PeachParts Mercedes-Benz Forum

mbzr4ever · #1 10-25-2007, 02:20 AM

Acky,

How could you be so lucky as to have the same problem with your 300e? Mine has almost 170K miles, is yours about the same? Does it seem to matter if it rainy/humid?

I hear you, these 300es are quite "sensitive" with all the electronics, which is why I prefer to drive my 240D as the daily driver.

Every post, though, suggested getting new plugs, wires, rotor and coil, if necessary. I was even scolded in this post:

91 300e problems because of the rain?

to expect such replacements as necessary maintenance items. The wires I replaced were bosch, and I cannot tell if they are the original or not without going back through the many years of maintenance records.

The wires, rotor/cap were all easy enough to change. But honestly, I don't notice much difference in how she sounds. Am planning to change the plugs by a mechanic on Friday (appointment is mainly for the front brakes).

That's interesting about the fuel pumps - yes, when it is hard to start, it sounds as if it has run out of gas.

Ok, keep in touch...

CamelotShadow · #2 10-25-2007, 03:23 AM

Pretty good for a girl
You did better than me
I whimped out after I did the rotor & cap
I broke a vacumn valve
after that
I put it back together
Figured I'd get help w the wires & plugs.

Took me forever to get them off the cap
finally did get them twisting turning w a pliers
Needed a tool
couldn't get enough strength from my fingers in the tight spot
After I figured it out
wires came off cap fine

They have a boot puller for the wires at plugs
thats good when you want to reuse

I just figured I did enough damage& I couldn't see risking more
for me to install wires that would have to come off to change plugs.

Luckily the broken part was cheap easy fix & might have been defective anyway...

Plugs can get tight esp if its a alum head & if they r installed wo anti seize.
Alum head is softer than the plug metal so overtightening or mistreading can be damaging.

No harm ever came from asking for help...

mbzr4ever · #3 10-25-2007, 03:46 AM

CamelotShadow,

Did you change the rotor/cap (and wires/plugs) because it was just a maintenance item or were you having specific problems with your engine?

I see you have the 500 SEC, so I'm assuming it was for this car? If it was for a problem, did this change take care of it?

CamelotShadow · #4 10-25-2007, 04:14 AM

Quote:

Originally Posted by mbzr4ever

CamelotShadow,

Did you change the rotor/cap (and wires/plugs) because it was just a maintenance item or were you having specific problems with your engine?

I see you have the 500 SEC, so I'm assuming it was for this car? If it was for a problem, did this change take care of it?

Yep
only have 1 benz
1st & only benz
thats it

I had a hot hard restart prob
was hoping maybe it would help but
really did it for maint
no real problems just wanting to make it better
think idle smoothed or that could be vac hoses too.

In fact mech saw cap & said its still good
rotor was burnt a bit

Its not humid here

I have heard the plastic covers on top the dis cap
can hold in mpisture & can be sources of problems
not sure if you have that kind?

It can't hurt to have new dis cap & rotor & igniiton wires plugs

My mechaninc changed the aculmulator
he thought thats why it was not starting hot

He may have got it as it started today after sitting 40 minutes
which ordinarlly would take alot of cranking

mbzr4ever · #5 10-25-2007, 04:36 AM

Quote:

Originally Posted by CamelotShadow

Yep
only have 1 benz
1st & only benz
thats it

I had a hot hard restart prob
was hoping maybe it would help but
really did it for maint
no real problems just wanting to make it better
think idle smoothed or that could be vac hoses too.

In fact mech saw cap & said its still good
rotor was burnt a bit

Its not humid here

I have heard the plastic covers on top the dis cap
can hold in mpisture & can be sources of problems
not sure if you have that kind?

It can't hurt to have new dis cap & rotor & igniiton wires plugs

My mechaninc changed the aculmulator
he thought thats why it was not starting hot

He may have got it as it started today after sitting 40 minutes
which ordinarlly would take alot of cranking

Are you talking about the black housing suppressor that goes over the cap? Hmmm, I thought as long as the cap was snug (I used slyglide aroung the rim too) it should keep the moisture out?

There is another black cover that goes over everything (wires/distributor) and someone (above) mentioned it was good to have to keep electrical interference away?

I do know that my old suppressor and cap were loose on the bottom, easily allowing moisture into the rotor area.

Glad to hear you have your problem fixed. You are lucky to have a good mechanic to help you along.

mbzr4ever · #6 10-25-2007, 04:43 AM

Just went over some previous posts - is there supposed to be a gasket between the cap and the rotor?

There is still the coil that could be the culprit.....is that difficult to change?

vegadonovan · #7 10-25-2007, 09:15 PM

Hi All,

I have the same stalling problem. It all started after I washed the engine bay.... It may or may not have been the sole cause, but it didn't have this problem before that, not even once.

When the stalling started, it was almost present every trip out driving. any speed night or day. I got really worried and had the car checked out by a mec who did some extensive testing and still found nothing seriously wrong as far as he can tell. Oh yeah the usual " Your transmission isn't the best and ..."

I drove off and got a Fuel Pump relay from the breakers. Its the only thing that is not expensive and easy to replace by me when it happens again.

So I change it out. It has not happened again. I can't tell if that was the cause. But we could never know. All I know is that I do not want it to happen again. period.

So now its ok. Given the choice again, I would still replace the relay.

Anyway I keep all the old relays in the trunk for spares on the road. They are cheap from the breakers.

Of course I don't keep a spare fuel distributor or Tranny.... hehe don't laugh.

mbzr4ever · #8 10-27-2007, 03:15 PM

Just an update on the new plugs that were replaced yesterday:

Sounds like an improvement. Engine idles noticeably smoother, but not 100% perfect. So it was a good idea to change these.

New brakes helped a lot, too, in making this car driveable again.

So it appears we are thinking this is a fuel pump related problem....thanks, acky for your insight.

Uncle Acky · #9 10-29-2007, 09:29 AM

You are very welcome mbzr4ever,

I have 2 files with info and instructions for you if/when your car stalls and wont start in future. Please e-mail me and I will attach in reply.

Good luck,
Acky

Uncle Acky · #10 10-29-2007, 08:56 PM

Well I thought I was on the right track but my problem is still there (hesitation and stalling when reaching operating temp, ONLY after car not driven for a few days. Again it's a 90 300E, I had tried the MAS unit from my wife's 92 300E when hesitation occured - no change - mas OK.

I had previously tested the pumps while stalled - no pump action -thus suspected posible mas unit defective.

Last week I swapped the OVP Relays because it feeds the mas unit in the pump relay circuit, although the 92 now did not malfunction, neither did the 90....until today. I purposely did not drive the car for about 4 days. Today it started and ran like a new car until it got to about 80 degrees, then it started to hesitate on light acceleration off idle. I drove it home keeping it at a fast idle (1000rpm) and tried to let it idle in the drive way. It stalled but restarted. the hesitation was there at idle and just above idle. It revs perfectly from 1000 rpm and up, smooth and not misfire.

Although it stalled it restarted and the only symptoms are hesitation/stumble at idle and reving from idle. I was so disapointed that I didn't feel like testing further.

This bugs me, it will run perfectly now untill it sits a few days.

Since other components tested OK I will now check how much current the fuel pumps draw (AMPS) when it runs fine and again next time it screws up.

Actually I will check the ICV first hmmmm yea that's it the ICV hmmmm.

I think I have two problems simultaniously. Ouch
Ack

mbzr4ever · #11 12-17-2007, 03:43 AM

Update:

The stalling out problem has not occurred since I changed the wires, plugs, rotor and cap. There was even a period of 10 days when I did not run it, even with the wet weather we have been having and it started up!

The idle is not a smooth as I would like, but I'm living with it for now. Added Sea Foam, and it made it sound even better.

I'm thinking the new suppressor/cap did the trick, since the old one was cracked. BWDIK, and keeping my fingers crossed...

Now I can get back to my 240D, ignition on again/off again problem...

brandob9 · #12 12-18-2007, 03:48 AM

Changing out the ignition related components is usually about half the cause of a poorly running car. You car needs three things to run: compression, spark and fuel. And unlike Meat Loaf, "Two outta Three" is bad.

Fortunately, the compression part is rarely an issue provided that the car sees oil changes regularly. It is a sweeping generalization to say that, but it works.

The ignition pieces simply get old and worn out. Everything rubber and electrical on the cars will. I discovered I the the original factory wires, cap and rotor on my car after 20 years on the road. Someone in 1986 did their job well.

The fun part, as you will probably find soon, is that the fuel mixture on the car is controlled by rubber and electrical parts. There are a number of ways for the system to fail. If air that the computer isn't expecting gets into the system, it throws the calculation off and the car will run poorly.

I've been on a campaign for a year now to slowly replace all the rubber pieces I can on that affect the way the car drives. Vacuum lines, hoses, joints, seals, you name it. All that stuff really makes a difference.

Good luck with the Benz. It is a complex car, but it follows simple ideas.