hard start no start - PeachParts Mercedes-Benz Forum

nisan17 · #1 08-06-2006, 10:21 AM

Hi Group,
As I mentioned in a preveious thread, August 1st I drove my 98 ML 320, 162k for a nonstop trip in 100 deg heat, with the last hour having no passing power, wanting to stall when giving gas.

Next day ran great.

August 4th ran for mostly 14hrs in 85 deg temp, no problem. Get home , half hour later very hard start, meaning it seemed like it wasn't getting gas , a few sputters...A few tries and it fires...Go grab a streak for my B-day, 1-1/2 hr later won't start at all. Just cranks and slight stumbles. No fuel pump noises that I could hear.

Call for a tow (free tow if I use the mechanic's service) He comes and says sounds like it's not getting gas. I really want to narrow this down because I know this shop has no experience with this type of vehicle. He did order software on the account of my abs/ets lights a few weeks ago. So he wants my business. The nearest specialist is 40 min away.

I don't want him playing a guessing game with my wallet at stake.

I've already left him a note on the seat stating it could be the CPS, as it wouldn't start the next morning either.

Appreciate any input. I'd drag it home and do it myself!

Kev

mbdoc · #2 08-07-2006, 08:06 AM

You are MOST likely on the right track with a flywheel crank sensor...very common failure

nisan17 · #3 08-07-2006, 09:47 AM

I'll keep you posted

nisan17 · #4 08-07-2006, 05:57 PM

Quote:

Originally Posted by M.B.DOC

You are MOST likely on the right track with a flywheel crank sensor...very common failure

Just got word from my independent mechanic. Scanner showed just an EGR code, no codes for CPS. Got it started and ran 1/2 hr with a fuel pressure reading of 47-59 psi and fluctuating. And a low of 16psi when backing it out of the garage. Says normal is 54-61 psi.

Says total estimate for repair would be $543. Does this sound okay? Does the scanner and symptoms match for fuel pump. I'm leary of his findings, of course because of his inexperience with MB ML's. I could be convinvinced!

azinn · #5 08-07-2006, 07:13 PM

Quote:

Originally Posted by nisan17

Just got word from my independent mechanic. Scanner showed just an EGR code, no codes for CPS. Got it started and ran 1/2 hr with a fuel pressure reading of 47-59 psi and fluctuating. And a low of 16psi when backing it out of the garage. Says normal is 54-61 psi.

Says total estimate for repair would be $543. Does this sound okay? Does the scanner and symptoms match for fuel pump. I'm leary of his findings, of course because of his inexperience with MB ML's. I could be convinvinced!

It is my understanding that CPS failure leaves no code. Good luck.

Gilly · #6 08-07-2006, 08:55 PM

The low pressure readings could be caused by the fuel pressure regulator, which is part of the filter. Has the filter ever been replaced and was it converted to the long filter?
Gilly

nisan17 · #7 08-08-2006, 12:13 AM

Quote:

Originally Posted by Gilly

The low pressure readings could be caused by the fuel pressure regulator, which is part of the filter. Has the filter ever been replaced and was it converted to the long filter?
Gilly

I've never replaced the fuel filter in the 1 1/2 yr I've owned it. Unknown of the conversion either. The previous owner didn't do anything but change the oil in the yr that he owned it, so he says. So there is no repair or maintainance paper trail. (he was getting a divorce)

So, it could be a bad filter/regulator? If he does the job, that will all be changed, correct?

Thanks

mbdoc · #8 08-08-2006, 07:53 AM

A bad crank sensor rarely leaves a code....start there...should be $100 part & less than a hour to install...they ALL seem to fail at some point!