I've been having a variety of problems with my 2005 Crossfire.
1. Back in November, the car would crank and not start for four days in a row but then in the morning started. Then later that day I tried to start it and it wouldn't start. Took to mechanic they couldn't firgure out what was wrong with it and couldn't replicate it.
2. About two months ago the car died twice in a week while I was driving. The first time it started right back up the second time it didn't start for a couple of hours.
3. I took it to the mechanic and they couldn't find anything wrong with it and could not replicate it. I asked them to replace anyways the crankshaft and camshaft sensors due to reading the forums.
4. After getting the car back though, almost every day it takes two cranks to start the car however it has not died while driving.
5. I resoldered the PCM after reading about it on the forums and that didn't fix it.
6. Took car to mechanic again they said that the key wasn't being recognized and also said they tested the fuel pressure and it was fine.
7. The car is at 86K miles and wonder if it could still be the fuel pump?
8. Ive tested with both keys I have and have same issue.
9. One key can unlock and lock the car remotely but, the other can't haven't been able to fix that.

What is the problem?

 

So, 4) says it now starts and does not die. Sounds like one of the sensor was bad.

BUt you also say it does not start on the first try. That kinda makes me suspect the sensor(s) they put in. Most shops will run to Autozone for sensors - in that case, sucks to be you. Your choices are to keep chasing this or put the RIGHT sensors in and see what you have after that.

Aside from that, I'd try this:

Get in car.
Turn key to ON.
Wait for a count of three or four.
Turn key to START.

Does it start on the first try then? If so, I'd say you have slow-to-build fuel pressure (which you can test with a simple fuel pressure test kit that costs under $50).

 

So I wanted the mechanic to use a bosch sensor but the mechanic said he didn't think that brand was good.
Instead, they went with an Echlin.
Do you think I should try to replace it?

 

Ever since joining the forum back in June 2009, the accepted standard is Go Bosch or Go Home (usually in a ride driven by someone else). Get both sensors replaced with genuine BOSCH (many say they are Bosch but are not, you have to be sure).


.

 

And find a new mechanic that knows Mercedese. You have a 2004 Mercedese SLK320.

 

You came here for help because you spent money and the car is still not right - non-Bosch crank sensors have been known to us to be a problem for at least 15 years, as George has pointed out.

What does that tell you?

As to ZERACER's comment, I offer this advice:
Search "2003 SLK320 Crank (or cam) position sensor" and ONLY buy from Autohaus, FCP Euro, German Auto Supply or Needwings. Many retailers sell "Bosch Equivalent" parts as "Bosch". DO NOT search for Crossfire parts.

 

Yes replace the sensors with BOSCH and I suggest you purchase it yourself to be certain what you are getting !!!
FCP Euro is a reliable supplier for these Bosch sensors
Then find another mechanic that understands a Crossfire or at the very least the Mercedes Benz

https://www.fcpeuro.com/products/mer...sor-0031532828 - Crank Position Sensor

https://www.fcpeuro.com/products/mer...sor-0232103037 Cam Position Sensor