At 105miles you need to change your plugs. It’s like when you were young you could jump over a puddle with ease. Now we’re old it’s a lot harder to jump over the same size puddle. The gap in your plugs has most likely increased a bit and the spark has to jump further. They are due for a change so try that first. I recommend NGK plugs.


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It could be a bad O2 sensor. The long-crank-no-start on the first try, followed by normal start straight after, was the only symptom of mine. It was intermittent.

You need to get the codes read.

 

Thanks Guys! I scanned for codes this evening and there were none stored. I checked the voltage to the cam sensor with the key turned on and verified that there is +12v there.

I started it a few times and it started fine.

I removed the cam sensor and cleaned the varnish off of it. It started several times (no problem, normal start) and I checked for codes a few times but there were none. I'll keep driving it and scan for codes when it fails to start next to see if it stores something.

I'm tempted to go ahead and buy a new cam sensor. Is that a smart move, or does it normally set a code if it's failing?

 

If there is no CAM code, why change it?

If your fuel pressure gauge is accurate, it would seem that 52psi is higher than the norm after 30 mins.

The fuel filters that you replaced, were they genuine M/B or aftermarket?

Check the amperage draw with the K2 relay removed in the right side kick panel fuse box. Two pieces of wire needed to insert in 30 & 87 for testing. Also check to see that fuse #13 is a 20 amp.

 

43sqd, Thank you for your reply!

I asked about the cam sensor to see if it is similar to the crank sensor, where it might be bad, but not leave codes. I don't want to change parts unless they are needed so I will keep troubleshooting.

I will measure the pressure drops more accurately and report back.

The new filter is Mahle 1634770801 and it also said KL438 on the filter "made in USA". It is aftermarket, not MBZ branded, but I believe it is the same as the OEM part. Please correct me if that's wrong.

I will follow the instructions to check the amp draw, check the fuse, and will report back.

Thank you again!

 

The new filter is Mahle 1634770801 and it also said KL438 on the filter "made in USA". It is aftermarket, not MBZ branded, but I believe it is the same as the OEM part. Please correct me if that's wrong.

It appears that the Mahle filters only lasted 30K each time and it should be assumed that they are faulty.

 

Cold fuel pressure results:
Running: 57psi
Off 0 min: 49psi
10 min: 50psi
20 min: 50psi
30 min: 50 psi

Hot Running: 57psi
Off 0 min: 51psi
10 min: 47psi
20 min: 40 psi
30 min: 35psi

20 amp fuse in position 13

I tried to measure the current draw for the fuel pump but I had my meter on the wrong setting and blew the fuse in the meter

I drove the car several times today and the problem is sporadic. Sometimes it fires right up. Sometimes it takes several attempts to start even though I'm watching the pressure gauge on the fuel rail and it has full 50 psi. I don't think I have a fuel problem.

I measured the battery voltage just in case. Resting it is 12.3 volts, while cranking it drops to 10.8 and running/charging it is 13.90. The battery is 3 years old and is top of the line Bosch.

I checked for codes several times and it is not storing any.

I'm back to the question again. Is it possible for the cam sensor to be failed and not set a code?

 

I don't think so, the ECU never misses that. for fuel issues: I'm currently driving with a weak pump, even a poor fuel delivery will throw codes soon especially with such hard starting or slight shudder under load. you will have system too lean bank 1 and 2. but it may come without codes earlier, but my belief is that the car will start just fine at the early stages of a fuel system problem then it will set the cel. i have cleared my twice in the last 3 days, its that weak that I've been getting the too lean 3 times in the last week, yet the car starts fine.

Try driving up a steep and see if it get tough. also one strange test, get into D immediately the car starts, if it dies and then runs very badly, your fuel could be weak.

your car is due for a new maf sensor and even o2 sensors at this age. if cost is an issue, try with used, verified parts.

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A failed cam position should set a code and turn on the check engine light.

 

Hard starting with no CEL has always been attributed to a fuel problem on this forum.

You replaced two previous filters which corrected the problem for approx. 10k miles.

Your cold stating shut down psi is 15 lbs. over the norm with the latest filter.

My only suggestion is to buy a genuine M/B filter 163 477 08 01 from a dealer and and take it from there.

 

Noodles, 43sqd,

Thanks, and that makes sense to me. I was surprised that the fuel filter change didn't solve the problem, and I'm going to go with that for the next step. I will buy an MBZ factory filter and replace it. I'll be back with the results!

 

Next step should be to read codes between 1st and 2nd start attempt. Code for CKP sensor/circuit self-clears on successful engine start.

Can be caused by coolant leak from expansion tank, dripping onto flywheel bell housing, for example.

 

DrX, thanks for the idea. If the MBZ fuel filter does not resolve the issue I will check codes after a failed start as you suggested.

I replaced my coolant tank about a year ago and have already changed the CKP sensor. the area is clean and dry so I'm OK there for sure.

 

Since you don't have a scanner(would have been nice though to read the codes) I wouls almost certainly say it's your MAF sensor. you hear people say it does cause a hard start but i can say confidently that it does. my ml320 had similar issue, will take up to 10 to 15 tries to start up, will die under little load. Simple issue, the maf sensors' connector was dirty. you won't believe this, just the connector, for 2 months I suffered this having cleaned the sensor severally with no luck, i just thought about the connector and that was it! car starts and runs like a ninja.

in your case i would suggest
1. clean maf, sensor, connector etc
2. remove battery to reset codes since no scanner, or use a scanner (the right thing to do)
3. test car... if it passes you're good if not
4. replace with original maf sensor from bosch

also check the catalyst in the exhaust it can get burnt and clogged and cause mysterious issues.

all the best Sir.

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noetico,

Thank you for all the ideas and suggestions. I did purchase a code reader and have scanned at least 15 times, cold, hot, right after driving it, etc. There are no codes stored. I will clean the MAF and the plug. It can't hurt anything!

I will have the MBZ filter in hand soon and that will get me a step closer.

I have zero driving issues. The car runs excellent, has full power, no rough idle, no problems at all. The issue is 100% with the long crank before starting.

 

ok Sir. if you clean the maf and you still have the issue, maybe get a used one from ebay, around 30 to 50usd to test. what do you think?

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Not to rock the boat, but I have used both genuine MB filters and they had the Mahle name stamped on them. So I have just been using the Mahle when needed and have had no issues with them.

 

I had this exact problem with my 2004 E320. Turns out it was a CAMSHAFT position sensor that was causing the problem. Never failed to start cold but would take 2-4 tries to restart once warm. Defective camshaft sensor..not too expensive and extremely easy to replace.

 

Thanks skasperski!

In all the reading I've done about others with the problem, the cam sensor has come up often enough that I will replace it as the next step if the MBZ fuel filter does not solve it (still waiting for that filter).

Also, I see you've been a member since 2011 and this is your first post?! Thanks for helping me with this!

 

New spark plugs should be next step, if not already done. Spark plug wires need not be replaced unless you have misfires. They don't wear out, although connector damage and corrosion may occur.

CMP sensor fault would be expected to trigger a code.

 

DrX, I have spark plugs (correct Bosch double platinum) on the way, as well as the tool to pop the leads off of the plugs. I will change them as well as the filter before moving to the next step.

Thank you!

 

hello 300ee320, hows it going

I think what I'm having with my car is basically the same as yours but mine is already worse so codes are thrown.

1. I have a hard start in the morning
2. I have codes for system too lean 1 and 2 (my fuel pumps are old ones, my bad), then interesting!! o2 sensor circuit low bank 1 sensor 1, this is the 2nd time in 2 months so obviously that sensor is aged and performance has degraded, I already got 2 from ebay coming in soon.
3. after it starts the first time it runs fine and will only start hard again if left for a long time.
4. after the first start it starts with a long and rough crank each time, but starts once
5. today the older if my 2 pumps totally went weak and the car will start and die, pushing the shredder valve at the fuel rail i got a very weak flow, so I put the stronger pump, and it was immediately a lot better.
6. My camshaft sensor threw a code 2 weeks ago, i cleaned it up and it was fine.
7. my crankshaft sensor is barely 2 years old, oem bosch part so still in top form, no issues with warm start at all.
8. months ago I bought bad fuel, dirty as mud, i had to wash the tank, I'm not saying you should do that but consider cleaning/changing that small filter attached to the pump if that hasn't been done


so...

i also cleaned the maf sensor and put a new fuel filter which solved 3 months of stalling and start-die cycles.

Summarily maybe we are both looking at

1. ensuring perfect fuel delivery, pump, filter etc.
2. cleaning the maf as a first step
3. cleaning the pump filter, carb cleaner does a perfect job here.
4. live stream o2 sensors and see their performance. consider changing since vehicle if vehicle is over 100k miles.


i have strong belief that doing this will solve the problem. for me I'm short of funds at the moment to replace so I'm managing used, aged stuff right now, but will receive some ebay used parts soon.


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hello 300ee320,

how's your progress with the car?

I decided to pull out my star and check if there are any codes the handheld code reader is missing and the star picked none as well(remember I have had lean and o2 sensor errors which i cleared and they didn't return, but hard start and even start and stall have progressed worse) .

interestingly, I decided to look at the lambda activity and yes, the same side that has thrown errors twice was totally not giving any useful signals. check attachment. this may be the problem with mine, maybe you check your live stream and see if youe o2 sensors keep switching from 0 to 1000mv, it should do so continually, if the voltage is steady low or high, you may look at that as a possible source.

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O2 sensors have nothing to do with your hard start. When you start the engine the ECM is in open loop & engine runs rich until it reaches the optimal temperature. Then the loop closes. Thats when ECM gets signals from O2 sensors. So look into your fuel delivery system.

 

agreed, as posted earlier, Im also tackling the fuel delivery, couldnt afford an oem fuel filter so I got some cheap after market one, then Im also aware my pump is almost gone. mine is a combination though, hard start plus sputtering, surging etc. so im doing all round maintenance, fuel delivery, maf sensor, o2 sensors, obviously that flat liner o2 sensor is impacting my ability to start and move smoothly. am i correct?

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Start the maintenance with the pump & filter. Do it in stages, so you can pinpoint your problem.

 

in fact, to confirm this just unplug the sensors, the car will start rough or hard and crank long. I've done this severally, its never smooth with weak or unplugged o2 sensors.

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My MBZ OEM fuel filter arrived. I installed it, and the problem was not resolved. It started fine cold, but took 4 tries after driving for 15 minutes and then sitting for 5 minutes.

I cleaned the MAF plug, but it was already very clean.

I replaced the spark plugs with the correct Bosch double platinums. This did not fix the problem.

There are no codes stored and after the failed try at starting, I scanned for codes and there were none.

 

Did you do o2 sensors?

I also have some very important update for you, it turned out that one of my major problems was serious corrosion on the battery's negative terminal, last week the car failed to start altogether.

On changing the terminals to new and shiny ones, it starts once, although still drags a while but always once, that's due to the fuel pump.

I would recommend you check
1. o2 sensors
2. battery terminals
3. fuel pump

did you clean or change the cam sensor?

Here's a post i made for cleaning the cam sensor

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Turn key to position 2. Wait for 10-20 sec and try. Does it start straight away?

 

Hi Art,

I did check this. With the fuel pressure gauge it builds pressure instantly when I turn the key to position 2. I had some tries when it did not start and I was actually watching the gauge and it had 50 psi of fuel pressure at the rail.

I think I have an electrical problem, not fuel.

Thanks!

 

From here I would look at injectors. They may have a real bad spray pattern. Try get an ultrasonic clean done on them.


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I cleaned the cam sensor too and verified it has voltage.

I'm going to take it in for a scan and proper diagnosis and I will report back what we find. I don't want to throw parts at this, and it's my wife's car so it has to be correct and dependable.

Thanks for the help, and I'll be back!

 

Alright, all the best. check the terminals at the battery for corrosion, check the earth cable from battery to chassis, if you suspect electrical, you may be right.

what type of scanner do you own? some good ones will actually scan the major systems and point out a short or open circuit.

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Before I replaced the Mahle filter, I would have redone the CKP sensor with a brand new Bosch or genuine MB one.

As these sensors age, some of them develop increased resistance when warm. This causes intermittent long-crank-no-start but not first thing in the morning.

 

DrX,

That was my thought process exactly and that's what I did. After I installed the Mahle filter and tested pressure at the fuel rail, I replaced the CKP with a new Bosch part, but it didn't fix the problem.

 

I would resound again: clean the battery terminals and the battery heads, make em like new or simply get new high quality ones. you could be having a simple voltage issue, erratic earthing, all sorts of issues arise, mine is so smooth now after changing the battery connectors (I had very similar issue as yours).

all the best Sir.

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noetico,

Thank you for all the suggestions! I agree completely that with electrical issues, the battery cables and grounds are critical to check. I removed the cables and wires from the ground lug on the firewall and scrubbed them all to shine like new. The negative clamp on the battery was the worst one and took a good amount of scrubbing. Unfortunately, it didn't fix the problem.