Originally Posted by pizzaguy

A car that sat three years? No way am I going to even try to guess at this, three year old gas and you expect the car to run right? Six month old gas can be a problem.

On that note:
There is no way I'd have allowed that old fuel to run thru those injectors. You can use a pump and pump the tank dry, then attach a fuel pressure test kit to the valve on the end of the fuel rail; you then manually close the fuel pump relay and make the pump run. While you are doing that, have a helper press and hold the release on the fuel pressure test kit and drain the fuel into a can. Once it's all pumped out, put in a gallon or two of new fuel and proceed from there.

I know it's too late for you, but for the next person.... This might seem like a lot of work and time -but it's not. And when you start the car, if it runs rough, you KNOW it's not fuel quality and since you can leave the test kit connected, if it runs rough or won't start, you know right away if you have proper fuel pressure (which is about 58psi, the car will idle down to about 20psi, but if you press the pedal it will die below about 30psi - ask me how I know!)

If you have pressure, you can move on to other items. This way, you gain knowledge of what is going on with the car quickly, which is helpful when things don[t go the way you want them to.
Oh, the OTC5630 kit is $40. Saves you SO MUCH time and frustration. When I meet some guy who "works on cars all the time" but has no fuel pressure test kit, I think: "This guy is thinking at all...." [u] Fuel pressure HAS to be right. Our cars (and most) do not monitor fuel pressure. If your pressure is way low or way high, the ECU has NO clue. The ECU assumes the pressure is right, if it's not right, it does not compensate for too much or too little fuel - and the car either won't run or wont run right. If you struggle making that car run right, I"d order a test kit and see what you have. I've had three Roadsters, have replaced the fuel pump on two of them, one around 90,000 miles (quit working), my SE at just over 60,000 miles (started leaking).

https://cimg4.ibsrv.net/gimg/www.cro...9fccb0c842.jpg

Originally Posted by Deepsea21

Then hook up the jumper cables again from your running car's battery and hook them to the terminals of the battery in your XF. Crank and fire the XF and if it keeps running and running for an hour then that leads to an alternator issue and eliminates bad grounds, etc. I assume you don't have a multimeter that could tell right away if your XF alternator is delivering charge that is making its way to the battery while running so this is one easy test.

Be warned, when you state that you are just gonna have it towed to the shop and let them fix it. That is gonna cost a fortune as Mercedes won't touch it and Chrysler may try and run you down a rabbit hole of $ as the techs around today have no clue about how to work on Mercedes. That leaves independent euro shops who know these old SLK 320's and can work on them and they are not cheap. Maybe you have that kind of $ and maybe you don't care. If so, good for you and have at it but for those who think they want to own one of these cars and have no tools or a clue how to maintain them they become deep, deep money pits. Just my 2 cents for what it may be worth.

Originally Posted by gblack32

I unfortunately do not have a multimeter