Bluetec No Start - Page 3 - PeachParts Mercedes-Benz Forum

DDAY · #31 03-28-2019, 03:19 PM

.Update on the no-start problem.
After leaving the car at the dealer for a month and paying $3,000 and the starting problem was not resolved. I decided to take the advice from forum members and others and try to fix it myself. The dealer replaced the high pressure fuel pump, left side fuel rail, and quantity control valve. Forum members suggested the primary fuel pump in the fuel tank, cam position sensor and crankshaft position sensor as possible problems. I replaced all these parts one at a time with no improvement.

I contacted an "old Mercedes mechanic" and told him this car starts perfectly when the engine is cold but when it is warm i can turn it off and then try to restart and it will not start. i wanted to get back to basics. I have many diesel engines of various ages on heavy equipment and i know if a warm engine gets fuel it will start when cranked. Therefore this car engine is not getting fuel when i try to restart it when warm. Where is the fuel shut valve? He told me the quantity control valve beside the high pressure fuel pump is a dual purpose device. It is the on/off solenoid fuel valve as well as a pressure control valve controlling the fuel pressure to the high pressure fuel pump. The dealer had already replaced this quantity control valve but i ordered a new one and replaced it again -- no good. One day when working on this problem in my shop where it was very quiet, furnace not running, radio off, no noise--i could hear a faint high pitched sound. The sound was coming from the front right side of the engine. Further exploring revealed that this sound was present immediately after i turned the engine off and lasted for a few minutes. I traced the sound to the glow plug controller. When the sound is active there are also a few clicks followed by a louder "thunk" and then the sound stops. With a warm engine, the car will not start while the sound is active. After the sound stops at the thunk, the car will start normally. If the engine is cold, it will stat normally and when i turn it off the sound starts but i can restart the engine while the sound is on. if the engine is up to normal operating temperature and i turn it off the sound is present and the engine will not restart until the sound stops and i hear the thunk.
i replaced the glow plug controller and the problem is still the same with one exception. The length of time the sound is present after a shutdown is a few seconds with the new glow plug controller where it could take several minutes for the sound to stop with the original glow plug controller.
The plow plug controller has two electrical connections. One connection has one large pin. The other connector has many pins (maybe 10 or 12). On older diesel cars this device is called the glow plug relay and it seemed to have one function -- turn the glow plugs on/off. What are the other functions of the glow plug controller in this engine?

This car is a 2009 E320. I also have a 2008 E320. I listened for this sound on the 2008. Sitting in the car,with the hood open and engine cover removed, i can hear the high pitched sound when i turn the engine off and there are also several clicks and the final thunk. The sound lasts 10 or 20 seconds and i can restart this car while the sound is active and with the engine hot or cold. Is there something different in the start up sequence between the 2008 and 2009 model years?

With the new glow plug controller the sound lasts for only about 10 to 20 seconds and then i can restart the engine. I can live with a short wait. The wait time at the beginning of this long story was sometimes as long as 20 minutes.

fritzkeel · #32 03-28-2019, 03:41 PM

This is really interesting. I recently bought a 2009 E320 Bluetec and live in Upstate New York. I was surprised at the short glow time, despite some really cold mornings the last couple of months. It would also crank and start, but sometimes die and I'd let it pre-glow again. Maybe my controller is failing as well? I also hear the sound you describe when I shut the car off. Fortunately, I have not had the no-start issues. I am interested to see what you figure out!

DDAY · #33 03-28-2019, 10:26 PM

These diesel cars are very good at starting in cold weather. We always have several days of -20F weather each winter. The 0M642 engine starts at that temperature just like it does on a hot summer day.

Winter before last I had my 2008 E320 parked outside for a few days in very cold weather. I drove it into my shop and raised up on the lift. It is a two post lift the raises the car by lifting on the body. The wheels dangle down. As soon as the car was up, I saw oil running onto the floor at the rear of the car. The oil was coming from the two rear shock absorbers. For some reason the shock absorbers did not like being fully extended when they were cold. Lesson learned, let the car sit in the heated shop for awhile before raising it in very cold weather.

jay_bob · #34 03-29-2019, 10:08 AM

Note the glow plugs on the OM642 (and probably the OM648) are not your grandpa's glow plugs on the older IDI engines.

First these are not 12 V glow plugs, they are rated in the single digit volts and the glow plug relay is really a PWM controller.

(PWM = Pulse Width Modulation, a very common technique for reducing the apparent energy delivered from a dc source, by turning it on and off rapidly in varying on-off ratios, used for everything from blower motors to tail lights in newer cars to modern Class D audio amps)

And these glow plugs are real firecrackers, they heat up so fast that at first I thought my GP light was broken on the dash when I first experienced an OM642. (Bought the car in the summer and it was warm so the GP was only on for a fraction of a second before starting).

I think the PWM allows them to vary the amount of heat they produce in a very short time, unlike the older IDI plugs that just have one speed.

Also please note that the glow plugs and controller have been superseded, and if the glow plugs are replaced the controller must also be replaced, because the voltages are incompatible. I ran into this on my ML320, had one glow plug fail and ended up having to replace all 6 and the controller.

So it also means that if you try to put a second gen controller on first gen glow plugs it won't work and may well damage them.

And yes the big fat wire on the GP controller is the battery feed. The smaller wires go to the glow plugs (one wire per plug) plus signal and control wires from the ECU. Probably just a LIN bus connection to the ECU.

I will try to pull out the car computer later and get the old/new GP and relay numbers from EPC and also look at the schematics to verify that the GP relay only deals with the glow plugs.

*Update
Old GP = A 001 159 58 01
New GP = A 001 159 66 01

Old GP Relay = A 642 153 37 79
First New GP Relay = A 642 900 27 00
Second New GP Relay = A 642 900 57 01

Checked schematics, the only connection on the control side is a LIN-Bus wire to the ECU, circuit 87 (protected +12 V dc for engine electronics), and ground. So it’s safe to say the glow plug relay (device N14/3) is only performing the glow plug management function.

DDAY · #35 03-31-2019, 10:54 AM

Drove the car for 90 miles and stopped at a rest area. Tried to restart the car 12 minutes later but it would not start. Waited 8 more minutes and tried again. Started normally. ?????????????

psaboic · #36 03-31-2019, 12:04 PM

I think maybe it is time for a priest to perform an exorcism......that rig is possessed.

Motorwagen · #37 04-06-2019, 12:45 PM

next time it doesnt start, get out and kick the fuel tank... we used to do this with vehicles at the dealership and it was a quick diag to see if the fuel pump in the tank was at fault. When they start acting this way they usually can be "bumped" a little and then they start working again.

motorwagen

DDAY · #38 04-07-2019, 09:50 AM

Thank you for the suggestion. They fuel tank on the car is rather hidden under the back seat -- not under the car. It would be difficult to kick it. I installed a new fuel pump in the fuel tank. I have removed the computer that controls the engine and sent it to a repair company for testing and repair if necessary. it should be returned to me in a few days. Again, this car is showing no error codes.

DDAY · #39 11-14-2019, 09:49 AM

This car is now repaired. It starts on the first try every time.

I replaced the starter. In doing so, I had to remove a section of the exhaust system to gain access to the starter. There were three wires going to "sensors" on the exhaust system that I had to unplug before removing the exhaust system. I don't know if replacing the starter or disconnecting the three wires and then reconnecting them solved the problem. The new starter does turn the engine a little faster.

I opened up the old starter and found the brushes to be very short. Ordered new brushes and installed them. That starter is now on the shelf just in case I need it in the future.

The new starter cost me $66.02 including freight. It looks exactly like the one I removed. Total cost of repairing this car was about $5,000 plus many hours of my own time. I bought the car at a discounted price because of known problems. The starting problem was a surprise. The car now runs perfectly and my total cost is about what a used car in top condition would sell for.

psaboic · #40 11-14-2019, 11:05 AM

Wow........That was a long haul, but I'm glad to hear the car seems to be fixed. I would think if one of the three sensors (or connections to them) were bad, a code would have been thrown. Those sensors should either be EGT sensors or NOx sensors.

barry12345 · #41 11-14-2019, 12:59 PM

This episode was far less than funny. I have to wonder if the old starter was pulling so much current the voltage dropped below some electronic components threshold. As the car operated it soaked up engine heat and that increased the starters internal resistance. So the voltage sag increased. Car sat and starter cooled down.

I have seem some mention of replacing batteries before they really age in many cars. Of modern types. I might do a load test on the current battery. Although not a lot of chance that was the issue. Yet if that battery does not test really great.

I suspect the issue is solved but an understanding of exactly how seemed to be lacking in my mind. Other than what I mentioned. Yes replacing the starter I know. It to me is just not superficially logical enough.

I have to buy cars with a lot of electronics and gadgets aboard. I have no intention of keeping them a long time. I will do methodical maintainance runs on them though. There is also no way we will be buying first year new engine cars.

To at least me that may have been the reason some of their models have two batteries. I am not a working mechanic though. This also is in hindsight. Still people with these cars should monitor the voltage when cranking. Making a note of it for future refferance.

Diseasel300 · #42 11-14-2019, 01:58 PM

I'd expect a bad, worn out, or weak starter to crank slowly or not crank at all. Cranking the engine over without it firing suggests a fuel or sensor issue, not a starter motor problem.

jay_bob · #43 11-14-2019, 03:14 PM

Y’all might be onto something with the voltage collapse theory. I saw many strange behaviors on my 2008 E320 with the electrical problems I had this summer that would square with your observations.

Low voltage sets an event not a fault if I remember right in most modules. That may only be visible on Xentry and not on a generic reader.

barry12345 · #44 11-14-2019, 03:44 PM

Quote:

Originally Posted by oldsinner111

I remember when electronic ignition replaced points.Alot of us did not trust it,Ford,and GM with modulator problems,and mopar with transistors.
Wished old tech could be brought back,but with cleaner fuels

You cannot have your cake and eat it too. At the same time complexity is usually harder and more expensive to deal with when it fails.

The Japanese seem to pay more attention in general to designing reliability of systems. Plus better quality control of many parts in them that are manufactured. Specifically Honda and Toyota.

Old technology just cannot produce the fuel millage and power of today. We also have lived through a long period of many manufactures producing a large range of cars. I do not know if this can be continued into the distant future.

Odd but I might have established the problem with this posters car. Had it been mine. Simply because of my electronic background. I knew of Mercedes two battery use and did not feel it was just for isolation. There also have been too many refferances around in the last while. To change batteries on a time basis rather that a deterioration one. On many newer cars. It has indicated to me that some cars electronics are really voltage sensitive.

I have already mentioned that I believe the excess current draw of his old starter pulled the general voltage too low. So some voltage dependant part did not become functional. Even some sensors will put out really bad information if operating at lower than their designed parameters. As usual not certain of this. Yet people might take readings of their voltage available as a refferance when cranking. Plus record it. Then when certain issues arise it is easy to check.

pawoSD · #45 11-15-2019, 03:51 PM

Batteries can be hit or miss too....I just replaced an 8 month old battery (east penn, good battery brand) on my brother's W211 after 8 months, it would go completely dead in hours if not kept charging. New MB battery, all fine and good.

Gotta love MB's design choice with the W211 to not include an under-hood jumper post like like W210 and pretty much all other MB's of the period (and beyond) have had.