Hi, all. I have searched the archive and have been reading posts about stalling 300E for the last a couple of days. However, most are pre-1990 model and there are some differences between these model years. So I am sorry to post this and thank you in advance for your reading and help.

My wife drives a 91 300E with about 110,000 miles. She started complaining about lack of power and even stalling on Mondays or days after the car was parked for a day or two. This usually happened at 3 miles form home or the engine just warmed up to operating temperature. Subsequent starting was easy sometimes but could also require excessive cranking at other times.

I have been driving this for the last week and I was able to reproduce this today. The car was not drive the last three days and I took it out today. At about 3 miles from home, the car sputtered when I push the accelerator paddle and eventually it stalled. I re-started it but it staled again and this happened a couple of times. I then waited for about 10 minutes and it started right up and ran perfectly.

Usually, after the first a few stalls, the car will run like new the rest of the week but would return on the following Monday.

This is a big mystery to me as under what condition it happened. I first checked the OVP fuse and it was fine. I then tried to find the fuel pump relay but could not. After some searching, it turned out that starting in the 1990 models, there is no separate fuel pump relay in the 300E. The fuel pump relay, AC relay, along with a couple other relays was integrate in the expansive MAS controlling unit.

I wonder if others have had similar problems. I hate to start throwing parts at it, especially that the MAS is over $300.

Thanks for reading.

No techical help, but at least a note of sympathy. Years ago, there was an article in a trade mag titled, "It won't start when I buy pistachio!"

A Texas gal with a Cadillac mystified her dealer when she complained that it always refused to start if she bought pistachio ice cream at her local Baskin-Robbins. After efforts that eventually included GM flying a tech crew down from Detroit, it turned out that the length of time it took to hand-dip a half-gallon of pistachio (as opposed to grabbing a prepacked one of chocolate or vanilla) was the perfect interval for a vapor lock to develop; insulating the fuel line to the carb fixed it.

Good luck--

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)

Thanks, Craig.

I saw you are in Grand Rapids and I am in Big Rapids.

I started on the simply things this morning. I tried to replace the spark plugs but only managed to do four out of the six. I could not pull the wire off the plugs on the other two. I guess I have to get the plug boot puller. Does anyone know if Auto-zone etc has a puller that will work or do I have to get the Mercedes puller.

The gaps of the four plugs I managed to remove are a little wider than spec but there is no sign of oil, etc.

Update:
I drove the car with four new plugs and two old ones to Auto Zones and it did not run too well but it did not stall. I got a plug wire puller for $9 and came home. I then managed to get the other two plugs replaced and the car ran much better.

I will wait to see if it stalls next week.

While the Lambda sensor is cold, the engine runs on preset failsafe numbers, then switches to loop control when the sensor is hot. Maybe something is happening at this point - read the codes at the diagnostic connector.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7