Cutting out at mid-high revs - Engine appears to stall at hi

[Rover]

Hi there, I have got two 1990 cars, a 300SEL (200,000k's) and a 420SE (45,000k's) both with the same problem. At low to mid demand/revs they both run nicely, as soon as you load them past this point (climbing hills, overtaking) they act as if they are running out of fuel, engine cuts, comes back, cuts, comes back until you back off the accelerator at which point they run normally again. I thought before I started stumbling around in the dark to change fuel filters, check relays etc, I would check to see if anyone here has had a similar problem and how it was resolved. HELP !!!!  

(Edited by Rover at 9:26 pm on Sep. 2, 2002)

 

[Spike]

Cutting out at mid-high revs

Sounds very likely that your HT leads need replacing.

 

[Andy]

Cutting out at mid-high revs

Hi

Before you start replacing stuff. Let your specialist take a look. Ask him to put the vehicle on is engine analyser and check the spark patterns and the engine. If nothing is evident. Get them to check fuel pressures especially under load.

If you just replace stuff it could cost you more than if you had it checked proffesionally. I have had this type of problem caused by water in the fuel also. So no matter what you change you will have the problem.

Hope this helps.

Regards

Andy @ www.mercedesservicing.com

 

[steveperry]

Cutting out at mid-high revs

Hi Rover,

My dad had almost the same problem with his '87 W124 - 200. After much investigation and very little help from most of the North London Stealerships (who wanted to replace various items, that ranaged from carbs to auto chokes, for a not so modest fee) the problem turned out to be that the engine was very badly coked, very thick deposits of carbon. After a full engine de-coke the car was totally cured. The worst symptom of the clogged engine was a total power loss when trying to accelerate up a moderate to steep hill.

 

[Richard Moakes]

Cutting out at mid-high revs

Had a similar problem many years ago, turned out to be a faulty fuel pump.

When was the filter last changed?  Is the pump any more noisy than usual?

Could be many things, but a filter is cheap insurance.

Richard
1989 W124 300E