Hello all,

My car is taking too long to start on a cold start but the check engine light has not come on...I replaced the CAMshaft position sensor (with Bosch sensor) about 2 years ago as well as the battery around the same time. Any ideas what it could be?

After it starts the first time, it will start the next several times without a problem.

 

Now before anything can be answered, what type of "long" cold start are we talking about?

Is it cranking over but not starting at all the first time? Or is it just cranking a couple/few more times than usual? The oil grade also has an effect on a cold start. If you have 0w-40 in the motor, you shouldn't have any issues. If you have 5w-40 in the motor, which btw is fine for our engine, it might crank a bit longer on very cold starts.

For my last oil change, I actually had 5w-40 put it from Mobile 1 by my local Loeber Mercedes dealer. They knew it was the same motor as the SLK so yeah. 5w-40 takes longer to crank on very cold starts, but so far mine has been fine. I will go back to 0w-40 before winter hits here in Chicago.

 

I actually just changed the oil last week and I'm using 0w-40.

Yes it is cranking a few more times than usual, I noticed it for the first time yesterday. Yesterday it took slightly longer to start but today it took significantly longer which has me worried.

 

Fuel related is my guess, the system is not holding or giving the correct fuel pressure.
Pump or filter issue.

 

A possibility is the fuel pump check valve going bad, not holding any pressure to the rail would cause a longer wait time to fire up the injectors. Try turning the key to the on position(no cranking)for 5 sec.'s, before trying to crank/fire it up. Does that help? If that doesn't help, then the problem is something else. Good luck.

 

I will try this tomorrow, thanks.

Thanks

 

I just tried this and after waiting 5 seconds the car started right away.

Before I cranked the engine, I heard this noise like as if the pump was trying to pump(?) followed by a knocking noise which subsided in about 5 seconds. Does that sound like what you were describing?

 

That sounds like the fuel pump going then, might wanna look at getting it replaced. Not sure how easy it will be to find one though.

 

http://www.ebay.com/itm/New-Mercedes-Benz-Electric-Fuel-Pump-BOSCH-0986580372-67968-OEM-MBZ-Pump-/251288585346?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3AChrysler%7CModel%3ACrossfire&hash=item3a81f78482&vxp=mtr
What about that one?

Is this something that I could replace myself? I'm no expert but I have done all the work on this car so far.

 

I know I'm not the leading expert on this forum either, so I'm gonna want Max, or 180, or maybe even ala_xfire to confirm this one. But that looks like the right pump from the image shown, and the price is about right too.


https://www.crossfireforum.org/forum...ome-notes.html <--- pump replacement guide for ya, should help out a bit

 

Thanks for all the help, I will try to replace the pump myself.

And I believe I will be ordering this pump:

http://www.ebay.com/itm/Mercedes-Benz-Fuel-Pump-Pierburg-OEM-7-22-15650-0007894-/271395877820?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ASLK320&hash=item3f307473bc&vxp=mtr
Another reputable company I believe and the price is a little better...

 

Yup, the SLK pump will do you just right, and that price certainly wont be worse for your wallet either hahahah. Let us know how it turns out if you replace it, or if you need more help with it.

 

Thanks man.

 

Tis why we are here good sir, tis why we are here.

 

Unless it has already been done, you should change out the old decaying fuel lines back there while you're into it. I didn't notice what year your car was, but my 05'(built in 04') is now a decade old.

 

Yes well my car is built in August '03 so its nearly 11 years old now

Are the fuel lines difficult to change? If not I may give it a go while I'm under there.

Also, any idea what size the fuel line is so I could pick some up in advance? And can I just buy a regular fuel or does it have to be high pressure etc?

 

https://www.crossfireforum.org/forum...verywhere.html

Here is a good thread to check out.

 

I'd do the filter first and forego the pump or both at the same time if the pump is ordered. It's uncomfortable and difficult to get the clamps off both. I clamped the lines but got gas all over myself anyway. In other words, it's better to have little gas than a full tank like I had.

Les

 

Thanks again

 

So it could be the filter that's the problem and not the pump? I was planning on changing both and the fuel lines at the same time.