jahquan3

I had misfiring still even after getting my coils and spark plugs replaced. So I dropped car off at the dealer this morning. The SA called me back and said I have bad pin connectors. I've never heard of these parts but to paraphrase he says it effects the cylinder/cylinders and is the cause of my car misfiring still.

The cost is just over $600 to fix so I just told them go ahead and do it since I'm tired of the headache. A search doesn't give me anything on these parts. Is anyone familiar with this or has anyone had this issue in the past on any of their vehicles.

bbirdwell

Yep. Loose pins and/or sockets. Cause intermittent connections. PITA to replace; very small, very tedious, very difficult to work with. Mercedes Electronic Parts Catalog shows the individual pins and sockets available for virtually all of the connectors.

jahquan3

Ok never heard of it and wasn't really sure how they even diagnosed it. I assume it doesn't come up on a scan so maybe a visual inspection? Either that or they are just taking shots in the dark since coils and plugs are now ruled out.

Thx for your response.

MBtech764

pins can definitely get loose and cause contact problems. The pins crimp onto the end of wires and are inserted into a specific slot in the connector; the pins are male and female, the male pin should fit tightly inside the female for 100% constant contact. The female pins are checked with a drag test. Basically you take a tester male pin and insert it in the female and drag it out. it should feel tight, any questionable play is a wiring repair. Could they be ignantly firing the parts cannon? definitely, but hopefully the pins fix it! good luck.

dubzino

How do you know when you are getting a misfire without throwing any codes?

dubzino

My car has an intermittent stumble while on idle. Is that a misfire?

jahquan3

I can always tell from the loss of horsepower when giving the car gas. When I was having ignition coil problems, it was very obvious and would stutter so to speak when I was accelerating almost enough that it would shake the car quite a bit.

When I was at a stop it would still shake a good bit. So you can probably tell at an idle as well. However each time I had misfiring there was always a CEL so I could pull a code. This time however it was the same P301 + P351 code. So I knew it was cylinder one but I changed out all the plugs and that coil so I knew it was something else just didn't know what.

jahquan3

Thx.

I got the car back a day later (Saturday afternoon). So far so good and I've driven about 150 miles since I picked it up. So let's hope this helps.

jahquan3

Just to clarify a couple of things about the $600 bill. After getting my detailed receipt back $299 of that was just for the Star Scan. My 3rd one in the past 3 months smh.

They replaced all 4 pins on cylinder one. That and the labor $245.99. Only $21 of that was for parts the rest was all labor.

They state they used a Borescope to look inside the cylinder. MB noted that "Coil 1 connector Pin 4 locations very loose". The removed Coil and Spark plug initially then tested if they were good then fixed pin connectors then reinstalled same coil and plug.

Just in case this happens to someone else, you shouldn't expect it to be 600 for just the pins and labor but more like 250-300ish.