cdi starting problems

[foler]

Re: cdi starting problems

I can hear low level sound zzzzzzzzzzzzzzzzz in key position 1 for about 5-6 sec, always. Sometimes engine start rough for 5-6 sec and battery light red on dashboard in this time.
Where is that low pressure pump? Maybe I can remove pipe behind pressure pump and turn key to view (live) flow.
Today I try to disconnect and reconnect brown jack in sam unit but no success.
I am 100% sure that engine dont get fuel.
And all of this after my trip in hot day when engine go to 240F water temperature. I turn off car to cool engine and after that I have nightmare with this sh of car!!!!!!!!!!!!!!!!!!!!!!!!!!!

[foler]

Re: cdi starting problems

today little sign for better days. I change my air filter and car start much better. But, after 10 min driving when engine is hot hard start again. I buy new fuel filter and two belts. Maybe this can help little. I suspect weak battery because engine start litlte rough for 5 sec and battery light is on on board. After 5 sec when engine catch good idle battery light turn off. On battery tester DIN standard tell that is bad and for N standard is good.
My battery have this specification: 390A, 44Ah, 12V. Today measured voltage is 12.9V.

how to check leak off on injectors - cdi? some post write that I need some litle pipes and some bottles. this is clear, but where to connect this pipes? please, pictures need. many mercedes owners have same starting problems and many of them tell about air leak into fuel lines and leak fuel in injector seals.

[foler]

Re: cdi starting problems

what is this big connector and is in green pipes for checking leak off injectors? I try to litle move this connector and car start like new for 5-6 times. But, again after one 10min driving cant start. New fuel filter no help. I realy suspect in air leak or leak off injector. How to disconnect this fuel lines from injectors to check leak off? Here is some metal retainer clip.

[foler]

Re: cdi starting problems

I HAVE AIR LEAK IN FUEL SYSTEM!!! Today I noticed air bubbles in this locations on picture. Any help how to find air source is welcome.
When I turn key to positin 1, bubbles cam in arrows direction on picture.
What is this 4th metal pipe in rail?

I think that this is source my starting problems.

[Mike T]

Re: cdi starting problems

That pipe is the high pressure fuel supply to the common rail.

Is this a Canadian cdi car in NJ USA?

[tolsen]

Re: cdi starting problems

I've never seen any air bubbles in the fuel pipes on my Cdi so air leaking into the fuel system may be the cause for bad start. The actual leak is not always that easily found. Air testing all low pressure fuel pipes using soapy water as detector is one method.
The fuel system does auto bleed so turning ignition on and off a few times before starting may result in more instant start.
Inlet fuel pipe is pressurized by feed pump submerged in the fuel tank. Pressure is around 2.5 bar. I wonder therefore how air can enter system without there being any visible fuel leaks. A fuel system diagram would obviously be of great help.

[foler]

Re: cdi starting problems

I spotted one place with some leak on top of the injector. Look picture.



Anyone can post fuel flow diagram???

Where I can buy connector for connecting fuel pipe to fuel filter? This connector with orange retainer clip. Or do I can bypass this plastic pipes and make some with rubber pipe.

[foler]

Re: cdi starting problems

which fuel pressure is needed for starting? My car have in idle around 245 bar and with starter turning engine pressure is around 360 bar. Is this good pressure for starting? We try different pressure regulator, no success. Last two days in the morning is litle colder (14C) and engine start ok. But after driving for several minutes, no start. I suspect weak starter because we today test battery and all is ok. I will report back in next several days.

[tolsen]

Re: cdi starting problems

You get fuel filter quick connector from Mercedes, but probably only available with the pipes. Parts are cheap, especially over here.

Your idle and start pressures are the same as mine so I assume normal.

My Cdi has sprung a leak in the high pressure pump in joint between a pump head and pump body. Engine still starts and runs fine in spite of pump now generating substantially less than 2/3 of its capacity.

This leak prompted me to research the system and I have now collected almost enough info so I may be in a position to publish a detailed description of the workings of the common rail system fitted on the Cdi. Only one little detail remaining: How does ECU work out when the cylinders can be fired without having a camshaft position sensor?

Leak caused by a tiny blown o-ring. Sourced a repair kit for about 10 pounds incl of shipment and hope to get my Smart back on the road by late tomorrow.

By the way, the high pressure pump is purely mechanical and generates high pressure at all times when engine is cranking. The little electrical connector is for 3rd piston cut-off solenoid whose purpose is solely to enable the pump to operate only two pumping elements, resulting in less engine power being absorbed at low engine loads.
Pressure is controlled by a fuel pressure control solenoid mounted on left hand side of fuel rail.

Read about Common Rail Diesel Fuel Systems by clicking here.
Note that the Smart has a Bosch CP1 type high pressure pump. This is the type that requires a diesel cooler.

[foler]

Re: cdi starting problems

....
Your idle and start pressures are the same as mine so I assume normal.
...Note that the Smart has a Bosch CP1 type high pressure pump. This is the type that requires a diesel cooler.

tolsen, I cant understand how pressure can be 350-370 bar when engine crank at maybe 200rpm with starter, and only 250 bar when idle at 750rpm?

diesel cooler? hmmm, diesel overheating? but my engine can be driven for maybe several minutes and I cant fire up. So I dont suspect that engine room is warm to "destroy" diesel.

Is it possible that injectors DONT get signal to inject fuel?

I will make video.

[tolsen]

Re: cdi starting problems

Higher pressure when cranking ensures easier start. Probably all 3 pumping elements are working when cranking. No need for the high pressure and extra volume when idling hence 3rd pumping element disabled and pressure is reduced.
Your diesel cooler is under the car under seat on a left hand side. Looks like it could be part of aircon but it is the diesel cooler. The diesel cooler is required as there is no supply metering to the pump. A large volume of leaked/ returned fuel means lots of heat and that is why the Smart has a diesel cooler.
Regarding no signal to injectors, I assume that is a possibility. How about checking whether injectors inject when you have a no start problem? You need to research how to do it. Perhaps remove an injector and visually check or use some kind of test tool to check if the injectors get any signal.

[foler]

Re: cdi starting problems

ufffff, another 100$ go in air for starter diagnose. This car is nightmare. Starter is ok. Engine start with start spray. One of my cylinder have 16 bar compression. I can to resolve this. But what if that dont resolve problem???? Why car start in the morning? I dont think that 15C (30F) difference in outside temperature can cause good start and good compression. I can measure compression when cold and when hot. Which is proper way to meassure compression? Do I need to disconnect injectors? How to know if source low compression is rings or valves?

I will use 3 gallon gas and fire this **** of car.:censor::censor::censor:

[foler]

Re: cdi starting problems

SAGA IS ended. RESOLVED. My valves seats is destroyed and engine cant have good compression. This is reason for hard starting. So, I repair cylinder head, new piston rings, rod bearings, oil....and now engine work properly. I spend almost same money for trying to identify problem and for rebuild. Uhhh, big mistake. I never will have again diesel engine.

Please, mark this thread RESOLVED.