Help! '95 W124 E420 wont go over 1000rpm
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Joined: Jul 2016
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2006 e350
Help! '95 W124 E420 wont go over 1000rpm
I had both distributors replaced with the wires and plugs (new). I have replaced the MAF sensor, used. I have pulled the throttle body and rebuilt the wiring harness. I have removed one of the cat converters. Finally, I replaced the o2 sensor.
Before taking it to a MB shop to have them look at it I could spray throttle body cleaner into the motor and it ran great for 20 or 30 mins. They then replaced the didistributors. This issue was an occasional one for about 6 months before it became constant.
The engine runs well up to 1000rpm and then it drops back down under it. This at idle or driving. I understand I could have gotten a bad MAF sensor and my rebuild of the wiring harness may still be the problem. The question I am asking here of you experts, and obviously you are experts, what else could it be?
Have a look and listen:
https://m.facebook.com/story.php?story_fbid=10154714563994506&id=56720450 5
Before taking it to a MB shop to have them look at it I could spray throttle body cleaner into the motor and it ran great for 20 or 30 mins. They then replaced the didistributors. This issue was an occasional one for about 6 months before it became constant.
The engine runs well up to 1000rpm and then it drops back down under it. This at idle or driving. I understand I could have gotten a bad MAF sensor and my rebuild of the wiring harness may still be the problem. The question I am asking here of you experts, and obviously you are experts, what else could it be?
Have a look and listen:
https://m.facebook.com/story.php?story_fbid=10154714563994506&id=56720450 5
Last edited by Aaron Barnes; May 21, 2017 at 01:12 PM.
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Joined: May 2017
Posts: 13
Likes: 1
From: Kitchener Ontario
1972 & 1973 350SL 1973 Bronco
I listened to your video. That is nasty the way it is hunting. The MAF measures air flow and reports to the computer to adjust air fuel mixtures. What happened when you was nplugged it? You had a few good suggestions there about vacuum leak. Go to your fuel rail and follow it to the fuel pressure regulator. Unplug the vacuum line from the regulator and pay attention if there is any fuel in the hose. Plug the hose and run it and see what happens. Pay attention if fuel squirts out the tube where the hose was plugged into. Two things can happen there. The diaphragm is damaged and is leaking into the intake through the vacuum line decreasing fuel pressure. If it is ok the spring could be broken in the regulator allowing for low fuel pressure in both scenarios. It needs to be able to maintain 35psi rail pressure and if it can't do that it will drop on its face. That would also exsplain your hunting idle. Another possible cause can be a faulty throttle position sensor. But try the other stuff first. Dave
