eric_in_sd

OK, MB wizards

About 10k miles ago, my 07 gl450 started cranking longer to start. This happened rather abruptly. It now takes 3 seconds or so to fire.

If I turn the ignition on, and wait for 10 sec before cranking, the engine starts quicker. Can't really tell but it seems about like it was before.

Not many comments on this out there, but it seems like this is a symptom of a leaking fuel pressure regulator - it releases the line pressure when the ignition is off.

If so, advice on replacement?

If not, where else to look?

alx

Your rail pressure needs to be read and determined if low/ rising slowly during crank, etc.

Too many variables to just say what is wrong with it

But I would start by pouring some chevron techron in the tank

BlownV8

When was the last time you changed your fuel filter?

eric_in_sd

Thanks, dude.

I put in a bottle of Chevron fuel injector cleaner every 1k miles. Also about half my gas is Costco, which is Top Tier where i get it.

eric_in_sd

Pretty sure it's never.

Mostly it runs just fine, but there was recently a jerking / hesitating in the first 30 seconds of driving. Didn't recur.

I'll go pull OBD2 codes and see what's in there.

I'm seriously tempted to just throw parts at it, that is if the replacements are not too expensive. Couldn't find the pressure regulators online, tho.

BlownV8

Change the filter first. It may be clogged in some way.

eric_in_sd

Thx. Looks like a wicked job, tho. You know much about it?

BlownV8

I have not but it does look like a tough job. I would try ALX's recommendation first.

alx

dont touch it is my recommendation.

have somebody with star/ das take a peek at your fuel rail pressure during start.

dont throw parts at it. forget money- nothing is more disheartening than replacing a part and finding out that was not the problem.

eric_in_sd

Thanks bro. When the parts are cheap, there is logic behind throwing parts at it. But you're right - the fuel filter & pump are like $400 for parts plus hours of labor. That's not a throwaway job.

I ordered an icarsoft. Hopefully it will give me fuel pressure readings.

Thanks again. Always appreciate the wisdom. You once said, that truck ages well, and it's very true and has helped me through dark times.

BlownV8

How many miles on your 450?

eric_in_sd

Just under 130k

Sure do hope that icarsoft unit will give me the info I'm looking for.

Nacho82

Does it crank longer every time you go to start, or only XX% of the time?

Does it sound like it is cranking slower than prior to this happening?

I have had a couple random weird cranks on my rig and was more curious about what you are experiencing. Maybe I am slowly having this same issue. I would describe what I have as a noticeable slow crank compared to the normal crank. Almost seems like the engine has gotten way higher compression. Then, the other weird thing would be cranking really long without starting. I actually had that happen last night after fueling up. I would say less than 7 times have "odd" cranks happened in 5 months, so it is super random.

eric_in_sd

I'd say it's like 90%. There does not seem to be a consistent pattern. Sometimes it's slow to crank when it's been sitting for just a few minutes.

Sometimes it struggles to get through a rev. Then it picks up again. Overall, I'd say it's somewhat slower, but not by a big amount.

Sounds like we are having the same symptoms, just that mine are much more regular.

I got the iCarSoft the other day, and I'll see if it can tell me anything about what's going on, and will report back.

qcman

Any update on this thread? Seems I have the same issue.

eric_in_sd

Nothing new. I never got around to researching whether I can view the fuel pressure. I'm distracted by what appears to be a failed injector.
The symptoms are now very consistent: Struggles on the first rev or two, then normal cranking for an excessive time (1-2 seconds) before normal start.
I suspect it is two problems: Low initial fuel pressure plus fatigued starter. I'll get the beast up and running and then change the starter.

qcman

Put in a bottle of durable lube fuel system treatment and filled up Sunday. Have had only one long crank since. Crossing fingers.

Kevin Beaumont

Just curious as to whether the durable lube fuel fixed the issue or if some other action was taken. We are having the same issue on our GL 450 too. Many thanks!

qcman

Hey Kevin,
Turned out to be a bad starter, replaced it and the noise went away.

eric_in_sd

I forgot to report back. I changed the starter and now the motor starts before the starter even engages.

Seriously, it's like in one revolution.

MB350ML

I have the same issue in my 2012 ML350 with new fuel pump and fuel filter

Tsumi

Initial long/slow crank, especially after just shutting off (i.e getting gas) is the starter going bad.

dwnsouf7

Hi...i need a fast reply guyz !!! was it a bad starter ? i got the Same problem ??

DennisG01

The fastest reply is the one already given - re-read the repsonses