Kadinc63

So i recent bought a 09 c63 amg with 120,000 miles. I love it and couldn’t be happier. BUT I’ve been doing some digging and it seems my car needs a few things.. the carfax only shows oil changes. I’m HOPING someone did their own repairs and maintenance before i got it. It runs great and runs strong especially to be 13 years old. Anyway here’s the list of weird things I’m experiencing..
1.) longer then normal turnover after it’s been sitting for a few hours. Cranks 4-5 times before it turns over.
2.) the first problem leads me to the next issue, WHERES MY COLD START ROAR?!? After it finally does start up, there’s no extra loud cold start like every other vehicle on the planet? What’s the deal?
3.) i took a video of the exhaust and redlined it twice. Black smoke came out of the tailpipes, gorgeous sound though.. too much fuel? Why?!?
4.) when I’m stomping on the gas to fam the RT challenger my friend loves, there’s a significantly loud whine. Almost like a supercharger. Anyone else having this issue? Vacuum leak??
5.) while this isn’t an issue, it’s more of a question.. what additives should i put in her to keep her alive?

i love my car, way better than my 2017 camaro and I’d like to get her in tip top shape ASAP!

JB63

The cold start roar depends on the temperature outside and your cars oil temp not dropping low enough while it sat. I currently also have the "supercharger" noise at wot which I'm guessing is a vacuum leak and will be taking care.

Kadinc63

it’s been in the 50’s over the weekend and when it cranks it’s equivalent to the idle. I’ve watched a lot of cold start videos and theyre all a lot louder than mine. Maybe when i get the turnover issue fixed it’ll solve both problems. I really would like to have an idea of what it is before i take it to my mechanic. And yeah i figured it was a vacuum leak, i read that the hose that’s near the fuel line is pretty faulty and is usually deteriorating pretty bad by 80k. I’m going to check it out this weekend and if it’s been replaced that’ll give me an idea on if any previous work has been done. If you find your leak give me a shout!

Southways

1: Possibly a leaky lifter draining the fuel rails. Caution: Could lead to a hydralock. A scanner will read the fuel pressure sensor & help with diagnosis.
2: It may have been recalibrated (tuned). Get it tuned by someone who knows these cars (refer other threads).
3: Black smoke usually = rich ... refer "1".
4: If it has a vacuum leak it will likely be running lean - get it fixed.
5: I have no conclusive experience/proof on additives I have tried.

hachiroku

on a stock motor on factory tune, taking longer to crank could mean a few things...spark plugs being old. if you are running extra rich requiring extra cranks i'd inspect injectors as they may be failing/sticking/sluggish/leaking, supercharger whine, not something that could really occur mechanically unless like others mentioned a vacuum leak.

Solo wing

I was hearing a supercharger whine under WOT. The cause was the front breather pipe (behind the oil filter housing and belt pulley) was completely disintegrated. Initially there was no codes, but as it got worse, fuel trims started rising and a CEL appeared. Replaced it and all is well.

Kadinc63

I’m going to change the injectors and spark plugs first. And I’m going to look for the leak. I’m definitely smelling fuel outside of the car when i get out.

Kadinc63

How time consuming is it to fix a leaking lifter? I’m going to check on it tomorrow.. hopefully if i fix that problem it’ll fix the smoke and fuel smell. I don’t think it’s been tuned but i will definitely find out. Even with no codes, can the scanner read the FPS?

Mort

I think Southways meant to say a leaking fuel injector not a leaking lifter.

Kadinc63

i wasn’t able to find the vacuum leak, I’m going to take it to my mechanic and see if they can find it. I ran some deadpan through the car, definitely not smelling as much fuel and i was but I’m still going to replace the injectors. And see if i can have the dealership flash the ecu to stock. It’s just pushing way too much fuel. Speaking of fuel, how many mpg do you guys get on average? I’m getting like 13-16 and i feel like that might be low.

hachiroku

good luck with the dealer. if tuned they most likely won't touch your car's computer. if they do, they won't unless you know the technician won't flash the computer as its a liability to as they cannot guarantee it won't brick your computer.

fuel consumption is really dependent on driving style. 13-16 isn't far off. are you certain you are running factory fuel injectors?

Kadinc63

im not certain to be honest. I’ll pull the fuel rail next weekend and switch them out either way. I was reading that the bosch injectors are good go-to’s

Southways

The injectors are "extended nozzle" variants. Ensure you get the correct model - ideally OEM & a matched set.

Kadinc63

So the previous owner took out the fuel Pressure regulator out and never put another one in, so gas was leaking under the seat where it is. Cleaned yo the gas, new o ring and FPR. Hasn’t leaked since and my car doesn’t have a long crank.

eightysixtuned

glad to hear you got this all sorted out.

Kadinc63

thanks man I would’ve never realized what it was if I hadn’t smelled that gas so much. I was really concerned because my son rides in his car seat in the back so I wanted to get it figured out as soon as possible. Killed two birds with one stone.