Help! My 1984 500SEL (US Spec), has a serious engine vibration at idle up to around 2000 rpm.. it also stalled a few times on initial start up then proceeded to get worse. My mechanic (not a Merc mechanic I live in the middle of nowhere) said it was the wrong kind of spark plugs and changed them and initially it worked, but he started it up again and the problem has persisted. He thinks it's the injector pump... (Do they have an 'injector pump' per se?). Any advice would be appreciated.
Member
let's start first, does the car start quickly or does it take a long time? on the first ball it acts as its an air flow sensor
should have ODB1 anyone check to see if it threw a code?
Quote:
It starts on the first try. Originally Posted by cylaptor
let's start first, does the car start quickly or does it take a long time? on the first ball it acts as its an air flow sensor
Member
then first replace the air filter and clean the LMM sensor with spray for the LMM sensor
OP your ‘84 500 SEL will have K-Jet for fuel injection. First thing to do is find a competent mechanic who is familiar with the car. Jethrow who can’t figure out a simple misfire is not going to be your guy.
Misfires.... Can be fuel, ignition, vacuum leaks (false air) or mechanical.
It is plenty old enough to be having issues with any of the above.
Misfires.... Can be fuel, ignition, vacuum leaks (false air) or mechanical.
It is plenty old enough to be having issues with any of the above.
Member
why would he need a good mechanic for a K-jet in the first place if it is one of the most demanding carburetor adjustment systems, then actually all owners of these models would need it, but they clearly don't have it. The problem is not in the K-jet
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Maybe. Rather difficult to tell when we are not the guys doing the diagnosis. We can merely make suggestions. Originally Posted by cylaptor
why would he need a good mechanic for a K-jet in the first place if it is one of the most demanding carburetor adjustment systems, then actually all owners of these models would need it, but they clearly don't have it. The problem is not in the K-jet
You’ve not seen issues with K-Jet?
Quote:
OBD I was mostly worthless. I have the tools to query it. Originally Posted by ygmn
should have ODB1 anyone check to see if it threw a code?
Quote:
Originally Posted by ikb435
Help! My 1984 500SEL (US Spec), has a serious engine vibration at idle up to around 2000 rpm.. it also stalled a few times on initial start up then proceeded to get worse. My mechanic (not a Merc mechanic I live in the middle of nowhere) said it was the wrong kind of spark plugs and changed them and initially it worked, but he started it up again and the problem has persisted. He thinks it's the injector pump... (Do they have an 'injector pump' per se?). Any advice would be appreciated.
Start with fuel syestem check :
1 replace the fuel filter.
2 "there is a fine mesh filter in the delivery pipe end at fuel distributer, likely that is clogged from the symptoms you have mentioned including a normal start.
proceed on from more fuel pressure check and volume,
OP most common is secondary ignition failure. Spark plugs, cap, rotor, plug wires. They fail with years as much as miles. Start there.
