How to check performance?
 

Hello friends,

I have a 1984 500 SEL and it doesn´t feel as powerfull as it should. At low rpms and at take off it works fine but seems sluggish at speed or slightly higher RPM:s. I will check the plugs, air filter and ignition for the basic faults but any input on trouble-shooting is appreciated.

Also I´m curious on how to check the fuel pressure (guess though that I should capture this when looking at the plugs for a rich or lean condition.

Is there any easy way to check the performance?

Thanks

Mikael Westerberg
Vanersborg, Sweden

To answer your basic question, it is unlikely that you will find anyone to do dyno comparisons to MBs performance specifications.

The best way to check it's performance is to take it to an experienced tech and have him drive it. Having driven thousands of 500SELs I could tell you in a five minutre test drive whether you were in specs.

As to fuel pressure the first thing you need to do is figure out what fuel pressure means to your car. if you think you will get any sort of indication of fuel pressure by looking at the plugs, you are a long way from needing gauges.

Just a bit of advise.
The get the biggest bang for the $$ you'll spend on your car to make it ''feel'' better, find a good/competent/reputable specialist and have your problems diagnosed.
Nothing is more frustrating (and expensive) than throwing parts at the car, not knowing exactly what is wrong with it.
Fuel pressure could possibly be a factor but there are probably 15 others reasons your car doe not ''feel'' to give you the performance you are anticipating.
JackD

Hi Guy´s,

I just thought I jump in on the post again and let You know how thing turned out.

I checked the things I mentioned in the post and it turned out that my airfilter really needed to be changed. The "funny" thing is that it didn´t look dirty or clogged but when I took it out and shaked it there was this big dust cloud around it full of sand, debris abd dead bugs.

I also advanced the ignition by 5 degrees (from TDC +/- 1 degree to 5 degreea BTDC. This and a new airfilter really impoved things. The car in now much livelier and the response when it needs air is a lot better.

(the old airfilter is only 1 year old and had about 10 000 Km on it)

Sometimes it really is the small tings that matters.

Best regards/ Mikael

Checkl your chain
 

If you had to retard your ignition 10 degrees your chain may be seriously stretched and in need of replacement, along with the rails and tensioner.

You may want to check this before your top end blows.

Hi again,

The chain, tensioner and rails are brand new and the cam timing is dead on (well almost). So I´m not worried about that. I advanced the ignition timing with 5 degrees to get a bit more performance. I´m keeping my ears open for any signs of pinging because of the advanced timing.

In most engines without a knock detecting sensor there is some room for advancing the ignition to allow for fuel variations and high ambient temperatures.

Since I´m living in Sweden and running on premium gas I though I give it a try.


Thanks/ Mikael

With premium fuel those early v8s could take a lot of timing advance. Even more so in countries where driving the car to its max is very illegal.

If you were running 130mph all day you might pay more attention to timing advance.