300E 1991 lack of power when warm
Thread Starter
Newbie
Joined: Nov 2019
Posts: 2
Likes: 0
From: Sweden
Mercedes G350D
300E 1991 lack of power when warm
I’m having issues with my 300E 1991 M103. Runs great at cold start both on idle and full throttle. But the warmer it gets the less I throttle I can use without choking/stalling it. It really feels like it's running too lean, more starvation the warmer it gets.
If I continue driving it (lower and lower speed to avoid stalling it with too much throttle) until full operating temperature it eventually starts to run poorly even on idle. If I then turn it off and restart it immediately, it backfires some and takes 5-10s before it starts and runs poorly.
If I wait until it's cooled down it runs great and accepts full throttle again.
Has anyone else experienced this problem?
If I continue driving it (lower and lower speed to avoid stalling it with too much throttle) until full operating temperature it eventually starts to run poorly even on idle. If I then turn it off and restart it immediately, it backfires some and takes 5-10s before it starts and runs poorly.
If I wait until it's cooled down it runs great and accepts full throttle again.
Has anyone else experienced this problem?
MBWorld Fanatic!
Joined: Mar 2016
Posts: 1,369
Likes: 195
From: SF Bay Area, CA
190E 2.6L 1989, 190E 2.6L 1988, BMW 535dXdrive 2014, BMW 428i 2015
I would start with the seed of the closed loop emissions control. Make use it is working/good. If it has more than 50K miles I would change it as precaution.
But before that, I would disconnect the EHA after the coolant temp reaches 70-80c. Tell us what happens.
There will be more diagnostics needed but I would like to first find out what happens when you disconnect the EHA on a warm engine.
But before that, I would disconnect the EHA after the coolant temp reaches 70-80c. Tell us what happens.
There will be more diagnostics needed but I would like to first find out what happens when you disconnect the EHA on a warm engine.
MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,621
Likes: 1,216
From: Phoenix
222 S-65
OP check fuel pressure. If a fuel filter has not been done in the last 30,000 miles replace it as preventative maintenance. A fuel pump relay could easily be failing as it heats up. Fuel pumps (yes; plural) must both be operating to be effective. Put a hand on each as it idles. You will feel the one that doesn’t work. If one is dead replace both. They are 35 years old.
