OlBoyCLK

first let me say thanks to all the contributors who have helped me thus far.

I have a 2001 clk 430 that starting yesterday wants to crank but not fire. It has had to crank a long tme to start intermittently for the last few months, but would always eventually fire on the first attempt. I did experience rough idling.

After reading through the forums, I began to suspect a few common perpetrators, one being Crankshaft Position Sensor.

So, i read that the Cps triggers fuel to be sent to the engine. if this is in fact the case, will I be able to test the shrader valve for fuel pressure while cranking if the cps is bad? Trying to diagnose and differentiate if it could be fuel pump, relay, or filter.

When i turn key to position 2, i hear the two clicks from the starter, but i also hear a whine coming from the rear of the engine block, around the MAF.


Any help is greatly appreciated, I really want to avoid a tow and trip to mechanic.

OlBoyCLK

The reason i am asking if the schrader fuel vabvalve can still be tested during cranking if the cps is bad, is because when i tested it during cranking nothing came out.

OlBoyCLK

So, the lack of pressure ended up being a bad fuel pump. if anyone else has a similar question, the crankshaft position sensor does not affect fuel pressure, and only engages injectors, so to answer my question, yes you will still get fuel pressure if the cps has gone bad.

Thanks, i think.