df666

I drive a 2000 ML and I have recently encountered starting problems. It takes about 2-3 attempts before it actually fires up. If I turn it off, it will immediately start, but if the vehicle sits for more than 15-30 minutes, the starting problem occurs again.
I recently replaced the fuel filter since I thought that it wasn't getting fuel (it needed the updated filter), but since replacing it, there has been no change. Is this a common symptom of a failing CPS? I've read several stories about the CPS on the forum, but they seem to differ a bit. Thanks in advance for your help!

sosh

Does not sound like a CPS. They usually fail with a hot engine that will not restart till it cools off. They also do not throw a code.

marcelc

As Sosh says it is unlikely to be the CPS, I suggest doing a fuel flow/pressure test but have no idea how to do it - any hints anyone?

Ryanr317

I wouldn't rule out the CPS. You should buy one and install it just so you never have to think back about it. It's not expensive or hard to install.

cward2

Fuel check valve stuck open bleeding fuel pressure to zero all the way back to the tank. Also a stuck injector pintle (or two) bleeding down pressure but you typically get a rough idle for a flash when that happens due to the fuel wash in the cylinder with the bad injector. Try running some Techron additive for a few tanks (not just gas with).

But as the guys above say, do the CPS anyway. Its easy and you eliminate diagnostic noise.

Chuck

jerryml

i had the same peoblem about two months ago and i took it to a guy that i trust and it was the cps and they charge me $240 to get it done on a 2001 ml430, good luck.
jerry

df666

Well, I replaced the CPS and the starting problems haven't changed, but it was easy to change and I won't have to worry about it! AutohausAZ seems to have the best prices on this part.
Cward2 suggested the fuel check valve; is this a replaceable part? Does anyone know where it's located? Thanks for all the help so far!

mr1320

your symptoms sounds a little different from mine. for me, it always starts fine but once in a while it will not start at all. when this happens, i could crank it 20-30 times and it won't start. i even turn on the ignition (without cranking) a few times to get the fuel pump primed and pressurize the system. it still wont start. then if i come back in 15-20 minutes, it fires right up like nothing was wrong.

i'm going to change my CPS tomorrow so i'll update my post with my results.

wish me luck!

Racin_fool

there are two more things that would cause this problem. Either the Fuel pump under the rear seat has finally taken a dump (not an uncommon thing to happen) or the fuel filter needs to be changed out.

benzeboy

df,
How old is your battery? had a similar problem. Replace battery and worked fine since. Good luck.

df666

Thanks benzeboy!
The battery is original and the car has around 71k miles, so I guess it wouldn't hurt to replace it. Did you replace yours with an OEM battery from the stealer? Just wondering what they want for them...
Does anyone know if my starting problem could be related to the fuel pump? I would think that if the fuel pump failed, the vehicle would not start at all, any thoughts? Thanks so far!

Racin_fool

The fuel pump would most likely be an intermittent issue unless it finally gave up the ghost.

As for the original batteries, we sell them for about $116 for those large white ones that come in them from the factory.

cward2

I suggest the factory supplied. My two favorite non-stealership shops both trek to the dealership for cars that need batteries. I think that's a pretty strong vote.

As for the intermittant issue and check valves, if it eventually starts every time, then the check valves or injector pintles aren't likely the cause. They just generally delay the initial "firing" that signals that its started. Now if you have a low battery too the cranking could reduce the battery voltage so that it doesn't fire the computer fully. Then you "rest" it a few minutes and the fuel is back in the lines and it fires. Maybe?

If you battery is 4 years or more, then your close anyway. As to the check valves and pintles, we usually address them with a couple of subsequent bottles of Chevron techron.

df666

Thanks again for the help so far guys!
I'm going to replace the battery this week. As for the starting symptoms, I can give a better explaination now that I've tried everything.
When I turn the key, the engine justs cranks and will not start (I guess the starting cycle has a time limit?) or I just let it crank and switch the key off before it finishes since I know it won't start anyway. However, on the second attempt it will start right away, or it will start after about 2-3 seconds.
Maybe this info will jog someone's memory? Again, thank you all so far, this forum rules!!!

cward2

thats exactly the fuel check valve injector pintle diagnosis if you say it doesn't happen if you shut off and restart but will happen nearly every time when you park it for 10-15 minutes or more.

BTW, the fuel guys at Shell used to tell us that high blended fuels (like with higher ethanol content) make the problem worse (lower viscosity I guess?).

df666

Hi guys,

Thanks again for the past help.
I am still having the exact same issues for the past few months. I was in the hospital for three months, so I'm just getting back into action.
Anyway, I have had several tankfuls of Techron and Chevron fill-ups and the problem is still present. The battery has been replaced, but I honestly believe it's the fuel check valve (I was using some questionable fuel for awhile when things were really expensive!)
Can this valve be replaced? After doing some research, I have found an "Injector Pump Solenoid", could this be the unit that the check valve is located in? It doesn't seem too expensive, am I on the right track?
I am hoping to avoid a trip to the "stealer" or a mechanic.

Thanks!
P.S. I just had the car lowered, I will post pics as soon as I am able.

df666

After checking a wiring diagram and looking under the hood, could the Purge Control Valve be causing my hard starting problem? It has what appears to be a fuel line going in and out from it and an electrical connecter.

df666

Hi Guys,

The original starting problem is still occuring, as you can see from the original post, it's been going on for months now. I am starting to think that maybe one or more of my injectors are bad.
Is it possible (or safe!) to visually check the injector spray pattern? And if so, how is it done? Do I pull the injector and just turn the key to position 2?
Please help...Thanks!

df666

Cward was right, it was the fuel check valve. Unfortunately, you have to replace the entire fuel pump assembly!
I replaced it two weeks ago and haven't had a problem since!
I hope this info helps someone who is having similar starting problems.
I believe the stealer charges around $1000, I did it myself for around $350!

stack

friend had a problem like this before ... it would take a long time to start..then it did not start at all.. the problems could be no fuel pressure , crank shaft sensors , or the filter

Solidjake

and that friend is mee.. i changed the fuel pump AND filter and the problem is still there. The car turns on once i let it cool down or whatever. definate CPS problem. taking it to the shop tomorrow and it will be done tomorrow. update on wednesday.

stack

lol u ***** .. i cant make my self look smart lol

Solidjake

got the car back from the shop today. drove it around for like an hour to get it really warmed up. parked it outside, added some trim to the car, turned it on like 40 min later, started with no problems. i will keep you guys posted.

Solidjake

been two days. car is running perfect

A GORDON

Recently been having intermittent reluctant starting issues with my year 2000 ML270CDI, particularly from either a cold start, or if the car has been running for some time and has got QUITE HOT, engine will turn on start, fire up after a few seconds, then immediately stall (OK when engine only warm, or only stopped for a short while)!!!!
When this happens, it will require a significant churn for 20 seconds, before it shows any sign of ignition, and sometimes does not at all, and car will have to be left for some time, before a re-start has any effect!!!
Very frustrating, because when the fault appears, first start nearly always works, and then stalls almost immediately!! It's after this point that re-start proves very difficult!!

Taken a stab and Crank Position Sensor now changed, and now starts fist time every time!!
Typical CPS fault of not starting reliably when engine was hot had also started rearing its ugly head when engine was cold too, which I understand is not such a typical symptom.
Seems to have corrected the fault nevertheless, so may be worth regarding with cold start issues too!!!