Back To The Drawing Board!
 

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

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...

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. :D

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.

Hi brandob9,


Good luck with your car, sounds like a good plan to watch the rubber parts for failure. Especially if they are easy to replace, it would be a good preventative measure.


That I could handle, but, the electronics?..totally different issue, I would not know where to start there! Talk about complicated!

Stalling solved
 

Well thanks to mbzr4ever for posting results, and although the symptoms were not identical to my stalling issues (detailed in this thread) I removed distributor cap and rotor for testing.

Resistance should be in the range of 700 ohms and 1300 ohms per teminal, the same for the rotor.

The rotor was not with in this range and I could not get a good reading.

Three terminals on the dist cap were within specs and two were not, one had no reading (infinity).

No cracks, flaws or carbon tracking.

I never suspected these parts because as long as I drove the car often withought letting it sit for more than a couple of days it ran perfectly rain or shine, hot or freezing cold, dry or pouring rain.

The similarity of mbzr4ever's problem led me to test the cap and rotor and having now just replaced these it runs like new all the time.

Take care,
Acky

Uncle Acky,

This is very good news. Glad to hear your new parts solved the problem.

Happy holidays to you and yours!

Seasons greetings everyone!